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Cohomology

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observed that it is fruitful to omit the dimension axiom completely: this gives the notion of a generalized homology theory or a generalized cohomology theory, defined below. There are generalized cohomology theories such as K-theory or complex cobordism that give rich information about a topological
7824:, and any two constructions that share those properties will agree at least on all CW complexes. There are versions of the axioms for a homology theory as well as for a cohomology theory. Some theories can be viewed as tools for computing singular cohomology for special topological spaces, such as 2722:
constructed an integral cohomology class of degree 7 on a smooth 14-manifold that is not the class of any smooth submanifold. On the other hand, he showed that every integral cohomology class of positive degree on a smooth manifold has a positive multiple that is the class of a smooth submanifold.
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induces an isomorphism on homology or cohomology. (That is true for singular homology or singular cohomology, but not for sheaf cohomology, for example.) Since every space admits a weak homotopy equivalence from a CW complex, this axiom reduces homology or cohomology theories on all spaces to the
9216:) that induce the zero map between homology theories on CW-pairs. Likewise, the functor from the stable homotopy category to generalized cohomology theories on CW-pairs is not an equivalence. It is the stable homotopy category, not these other categories, that has good properties such as being 8319: 737: 7820:). (Here sheaf cohomology is considered only with coefficients in a constant sheaf.) These theories give different answers for some spaces, but there is a large class of spaces on which they all agree. This is most easily understood axiomatically: there is a list of properties known as the 7107: 73:, this idea became a dominant method in the mathematics of the second half of the twentieth century. From the initial idea of homology as a method of constructing algebraic invariants of topological spaces, the range of applications of homology and cohomology theories has spread throughout 9211:
A subtle point is that the functor from the stable homotopy category (the homotopy category of spectra) to generalized homology theories on CW-pairs is not an equivalence, although it gives a bijection on isomorphism classes; there are nonzero maps in the stable homotopy category (called
8898: 7476: 6882:, more powerful tools are required because the classical definitions of homology/cohomology break down. This is because varieties over finite fields will only be a finite set of points. Grothendieck came up with the idea for a Grothendieck topology and used sheaf cohomology over the 1546: 337: 7643: 7238: 1331: 2750:. The cup product corresponds to the product of differential forms. This interpretation has the advantage that the product on differential forms is graded-commutative, whereas the product on singular cochains is only graded-commutative up to 6672:
In a broad sense of the word, "cohomology" is often used for the right derived functors of a left exact functor on an abelian category, while "homology" is used for the left derived functors of a right exact functor. For example, for a ring
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says that every generalized homology theory comes from a spectrum, and likewise every generalized cohomology theory comes from a spectrum. This generalizes the representability of ordinary cohomology by Eilenberg–MacLane spaces.
8612: 9189: 7790: 6958: 3637: 7394: 4436: 2306: 216: 5972: 58:. Cohomology can be viewed as a method of assigning richer algebraic invariants to a space than homology. Some versions of cohomology arise by dualizing the construction of homology. In other words, cochains are 9029: 8452: 4594: 5733: 6805:
There are numerous machines built for computing the cohomology of algebraic varieties. The simplest case being the determination of cohomology for smooth projective varieties over a field of characteristic
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Also, every integral cohomology class on a manifold can be represented by a "pseudomanifold", that is, a simplicial complex that is a manifold outside a closed subset of codimension at least 2.
591: 1188: 2429: 1718:{\displaystyle 0\to \operatorname {Ext} _{\mathbb {Z} }^{1}(\operatorname {H} _{i-1}(X,\mathbb {Z} ),A)\to H^{i}(X,A)\to \operatorname {Hom} _{\mathbb {Z} }(H_{i}(X,\mathbb {Z} ),A)\to 0.} 5594: 1134: 1059: 5532: 5195: 7330: 6830:
help give computations of cohomology of these types of varieties (with the addition of more refined information). In the simplest case the cohomology of a smooth hypersurface in
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is an important computational tool in cohomology, as in homology. Note that the boundary homomorphism increases (rather than decreases) degree in cohomology. That is, if a space
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If one prefers homology or cohomology theories to be defined on all topological spaces rather than on CW complexes, one standard approach is to include the axiom that every
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Although cohomology is fundamental to modern algebraic topology, its importance was not seen for some 40 years after the development of homology. The concept of
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Here are some of the geometric interpretations of the cup product. In what follows, manifolds are understood to be without boundary, unless stated otherwise. A
5076: 3528: 4319: 2185: 8944: 8367: 8314:{\displaystyle \cdots \to h_{i}(A){\overset {f_{*}}{\to }}h_{i}(X){\overset {g_{*}}{\to }}h_{i}(X,A){\overset {\partial }{\to }}h_{i-1}(A)\to \cdots .} 732:{\displaystyle \cdots \leftarrow C_{i+1}^{*}{\stackrel {d_{i}}{\leftarrow }}\ C_{i}^{*}{\stackrel {d_{i-1}}{\leftarrow }}C_{i-1}^{*}\leftarrow \cdots } 82: 6113: 7102:{\displaystyle H^{k}(X;\mathbb {Q} _{\ell }):=\varprojlim H_{et}^{k}(X;\mathbb {Z} /(\ell ^{n}))\otimes _{\mathbb {Z} _{\ell }}\mathbb {Q} _{\ell }} 7674: 1957: 8893:{\displaystyle \cdots \to h^{i}(X,A){\overset {g_{*}}{\to }}h^{i}(X){\overset {f_{*}}{\to }}h^{i}(A){\overset {d}{\to }}h^{i+1}(X,A)\to \cdots .} 4451:
Another interpretation of Poincaré duality is that the cohomology ring of a closed oriented manifold is self-dual in a strong sense. Namely, let
7471:{\displaystyle {\begin{matrix}E&\longrightarrow &Bl_{Z}(X)\\\downarrow &&\downarrow \\Z&\longrightarrow &X\end{matrix}}} 4157: 10186: 7336:
which behave similarly to singular cohomology. There is a conjectured theory of motives which underlie all of the Weil cohomology theories.
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Cohomology theories in a broader sense (invariants of other algebraic or geometric structures, rather than of topological spaces) include:
5879: 6459:, and realized that Poincaré duality can be stated in terms of the cap product. Their theory was still limited to finite cell complexes. 6070:
to make them intersect transversely and then taking the class of their intersection, which is a compact oriented submanifold of dimension
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to define the cohomology theory for varieties over a finite field. Using the étale topology for a variety over a field of characteristic
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used in his proof of his Poincaré duality theorem, contained the beginning of the idea of cohomology, but this was not seen until later.
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space, not directly accessible from singular cohomology. (In this context, singular cohomology is often called "ordinary cohomology".)
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whenever the variety is smooth over both fields. In addition to these cohomology theories there are other cohomology theories called
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determines both a generalized homology theory and a generalized cohomology theory. A fundamental result by Brown, Whitehead, and
86: 9735: 10805: 9708: 5756: 332:{\displaystyle \cdots \to C_{i+1}{\stackrel {\partial _{i+1}}{\to }}C_{i}{\stackrel {\partial _{i}}{\to }}\ C_{i-1}\to \cdots } 6512:
is a rich generalization of singular cohomology, allowing more general "coefficients" than simply an abelian group. For every
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is the homology of this chain complex (the kernel of one homomorphism modulo the image of the previous one). In more detail,
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to make the product graded-commutative on the nose. The failure of graded-commutativity at the cochain level leads to the
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The axioms for a generalized cohomology theory are obtained by reversing the arrows, roughly speaking. In more detail, a
5387: 417: 10848: 2559: 6661:(but usually now just "cohomology"). From that point of view, sheaf cohomology becomes a sequence of functors from the 4766: 1163: 10340: 10313: 7803: 2565: 6653:
That definition suggests various generalizations. For example, one can define the cohomology of a topological space
3691:/2 coefficients works for arbitrary manifolds. With integer coefficients, the answer is a bit more complicated. The 2351: 10715: 10283: 10215: 9463:
and so on. Complex cobordism has turned out to be especially powerful in homotopy theory. It is closely related to
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The first cohomology group of the 2-dimensional torus has a basis given by the classes of the two circles shown.
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theory, is more natural than homology in many applications. At a basic level, this has to do with functions and
10786: 10514: 9094: 3743: 3459:= in degree 2. (Implicitly, orientations of the torus and of the two circles have been fixed here.) Note that 2714:
is a noncompact manifold, then a closed submanifold (not necessarily compact) determines a cohomology class on
5485: 2718:. In both cases, the cup product can again be described in terms of intersections of submanifolds. Note that 10800: 9815: 6730:) can be viewed as a "cohomology theory" in each variable, the right derived functors of the Hom functor Hom 6415: 2754:. In fact, it is impossible to modify the definition of singular cochains with coefficients in the integers 160: 7825: 7638:{\displaystyle \cdots \to H^{n}(X)\to H^{n}(Z)\oplus H^{n}(Bl_{Z}(X))\to H^{n}(E)\to H^{n+1}(X)\to \cdots } 5156: 10735: 10730: 10656: 10533: 10521: 10494: 10454: 9840: 9825: 9775: 9760: 9283: 8634:) from the category of CW-pairs to the category of abelian groups, together with a natural transformation 7916: 7892: 7333: 6591: 4711: 210: 59: 7297: 7233:{\displaystyle X={\text{Proj}}\left({\frac {\mathbb {Z} \left}{\left(f_{1},\ldots ,f_{k}\right)}}\right)} 2937: 2686:
do not intersect transversely, this formula can still be used to compute the cup product , by perturbing
1326:{\displaystyle \cdots \to H^{i}(X)\to H^{i}(U)\oplus H^{i}(V)\to H^{i}(U\cap V)\to H^{i+1}(X)\to \cdots } 10577: 10504: 9810: 9740: 9217: 8517: 6466:
overcame the technical limitations, and gave the modern definition of singular homology and cohomology.
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On the other hand, cohomology has a crucial structure that homology does not: for any topological space
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Many of these theories carry richer information than ordinary cohomology, but are harder to compute.
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groups, based on studying a space by considering all maps from it to manifolds: unoriented cobordism
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manifold (possibly with boundary), or a CW complex with finitely many cells in each dimension, and
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Some of the formal properties of cohomology are only minor variants of the properties of homology:
488: 6477:, they proved that the existing homology and cohomology theories did indeed satisfy their axioms. 3086: 2757: 2542:, called . In these terms, the cup product describes the intersection of submanifolds. Namely, if 1342: 10770: 10720: 10641: 10631: 10509: 10489: 10429: 9845: 9835: 9770: 9730: 9377: 7837: 7829: 7808:
There are various ways to define cohomology for topological spaces (such as singular cohomology,
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and Alexander both introduced cohomology and tried to construct a cohomology product structure.
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structure. Because of this feature, cohomology is usually a stronger invariant than homology.
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There is a related description of the first cohomology with coefficients in any abelian group
2877: 2829: 2747: 1388: 1336: 957: 910: 340: 179: 106: 51: 6695:) form a "homology theory" in each variable, the left derived functors of the tensor product 3134: 3044: 10538: 10484: 10413: 10240: 10203: 10138: 9830: 9805: 9236: 8324: 7896: 7817: 7342: 6662: 6603: 6581: 6577: 6504: 6463: 6245: 5327: 4782: 4754: 4632: 3341: 925: 78: 10425: 10388: 10358: 10301: 10266: 10233: 10196: 10163: 7277: 6909: 5204: 5129: 4244:
Alternatively, the external product can be defined in terms of the cup product. For spaces
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with an orientation on the normal bundle. Informally, one thinks of the resulting class
1523:{\displaystyle \cdots \to H^{i}(X,Y)\to H^{i}(X)\to H^{i}(Y)\to H^{i+1}(X,Y)\to \cdots } 10687: 10619: 9795: 9468: 7651: 6889: 6865: 6809: 6541: 6448: 6399: 5315: 2751: 2061:
defined by an explicit formula on singular cochains. The product of cohomology classes
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be an oriented manifold, not necessarily compact. Then a closed oriented codimension-
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This has the effect of "reversing all the arrows" of the original complex, leaving a
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On any topological space, graded-commutativity of the cohomology ring implies that 2
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corresponding to the trivial double covering, the disjoint union of two copies of
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Sheaf cohomology can be identified with a type of Ext group. Namely, for a sheaf
202:, the cohomology ring tends to be computable in practice for spaces of interest. 10780: 10692: 9213: 9204: 8607:{\displaystyle \bigoplus _{\alpha }h_{i}(X_{\alpha },A_{\alpha })\to h_{i}(X,A)} 6678: 6473:
defining a homology or cohomology theory, discussed below. In their 1952 book,
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Another useful computational tool is the blowup sequence. Given a codimension
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is in one-to-one correspondence with the set of isomorphism classes of Galois
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When considering varieties over a finite field, or a field of characteristic
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Alexander had by 1930 defined a first notion of a cochain, by thinking of an
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in degree 0. By homotopy invariance, this is also the cohomology ring of any
10661: 9785: 9332: 9184:{\displaystyle h^{i}(X,A)\to \prod _{\alpha }h^{i}(X_{\alpha },A_{\alpha })} 7785:{\displaystyle H^{n}(Bl_{Z}(X))\oplus H^{n}(Z)\cong H^{n}(X)\oplus H^{n}(E)} 6713: 1885: 1537: 1398:. They are related to the usual cohomology groups by a long exact sequence: 1148: 2694:
to make the intersection transverse. More generally, without assuming that
9703:. In the language of spectra, there are several more precise notions of a 4154:) can be defined as the pullback of the external product by the diagonal: 3703:
of degree 2 such that the whole cohomology is the direct sum of a copy of
3221: 10646: 10614: 10563: 10470: 9475: 4710:). Informally, the Euler class is the class of the zero set of a general 3632:{\displaystyle H^{*}(X\times Y,R)\cong H^{*}(X,R)\otimes _{R}H^{*}(Y,R).} 3233: 1831: 74: 70: 6594:
elegantly defined and characterized sheaf cohomology in the language of
6572:). Starting in the 1950s, sheaf cohomology has become a central part of 10417: 9478:, based on studying a space by considering all vector bundles over it: 7876: 4431:{\displaystyle u\times v=(f^{*}(u))(g^{*}(v))\in H^{i+j}(X\times Y,R).} 3197:
In what follows, cohomology is taken with coefficients in the integers
944: 9717:, where the product is commutative and associative in a strong sense. 2301:{\displaystyle uv=(-1)^{ij}vu,\qquad u\in H^{i}(X,R),v\in H^{j}(X,R).} 10247:, Graduate Texts in Mathematics, vol. 52, New York, Heidelberg: 6422: 5967:{\displaystyle H^{i}(X,R)\to \operatorname {Hom} _{R}(H_{i}(X,R),R),} 10100: 7915:
is a subcomplex) to the category of abelian groups, together with a
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One of the Eilenberg–Steenrod axioms for a cohomology theory is the
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then there is an equality of dimensions for the Betti cohomology of
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and whose other homotopy groups are zero. Such a space is called an
9641:, Morava E-theory, and other theories built from complex cobordism. 5126:(defined up to homotopy equivalence) can be taken to be the circle 9024:{\displaystyle h^{i}(X,B){\overset {f_{*}}{\to }}h^{i}(A,A\cap B)} 8702:) induces a long exact sequence in cohomology, via the inclusions 8447:{\displaystyle h_{i}(A,A\cap B){\overset {f_{*}}{\to }}h_{i}(X,B)} 4589:{\displaystyle H^{i}(X,F)\times H^{n-i}(X,F)\to H^{n}(X,F)\cong F} 3298: 3220: 9975: 9973: 5728:{\displaystyle \cap :H^{i}(X,R)\times H_{j}(X,R)\to H_{j-i}(X,R)} 1159:
induce the same homomorphism on cohomology (just as on homology).
8124:) induces a long exact sequence in homology, via the inclusions 7668:
is smooth, then the connecting morphisms are all trivial, hence
6395:. This result can be stated more simply in terms of cohomology. 10443: 6216:
There were various precursors to cohomology. In the mid-1920s,
6186:{\displaystyle H^{i}(X,R){\overset {\cong }{\to }}H_{n-i}(X,R)} 4022:
The cup product on cohomology can be viewed as coming from the
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for the two projections. Then the external product of classes
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for vector bundles that take values in cohomology, including
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spanned by the element 1 in degree 0 together with copies of
140:. The most important cohomology theories have a product, the 8688:: Homotopic maps induce the same homomorphism on cohomology. 6657:
with coefficients in any complex of sheaves, earlier called
6260:)-cycle. This leads to a multiplication of homology classes 5078:
denotes the set of homotopy classes of continuous maps from
2054:{\displaystyle H^{i}(X,R)\times H^{j}(X,R)\to H^{i+j}(X,R),} 81:. The terminology tends to hide the fact that cohomology, a 27:
Sequences of abelian groups attached with topological spaces
10439: 10400:"Quelques propriétés globales des variétés différentiables" 10090:, p. 117, 331, Theorem 9.27; Corollary 14.36; Remarks. 6859:
can be determined from the degree of the polynomial alone.
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can be identified with a function from the set of singular
8110:, then the induced homomorphisms on homology are the same. 6568:
a manifold or CW complex (though not for arbitrary spaces
6491:, building on work of Alexander and Kolmogorov, developed 4235:{\displaystyle uv=\Delta ^{*}(u\times v)\in H^{i+j}(X,R).} 190:; this puts strong restrictions on the possible maps from 6793:, and Ext is taken in the abelian category of sheaves on 6610:
to abelian groups. Start with the functor taking a sheaf
5844:{\displaystyle H^{*}(X,R)\times H_{*}(X,R)\to H_{*}(X,R)} 6789:
denotes the constant sheaf associated with the integers
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as a function on small neighborhoods of the diagonal in
6351:{\displaystyle H_{i}(M)\times H_{j}(M)\to H_{i+j-n}(M),} 6193:
is defined by cap product with the fundamental class of
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coefficients is isomorphic to the de Rham cohomology of
2662:, with an orientation determined by the orientations of 209:, the definition of singular cohomology starts with the 3083:
restricts to zero in the cohomology of the open subset
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means a compact manifold (without boundary), whereas a
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The corresponding homology theory is used more often:
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Some examples of generalized cohomology theories are:
7399: 5153:. So the description above says that every element of 4826:. This space has the remarkable property that it is a 10101:"Are spectra really the same as cohomology theories?" 9669: 9598: 9562: 9523: 9484: 9427: 9380: 9341: 9291: 9244: 9103: 8947: 8736: 8526: 8370: 8163: 8060: 8004: 7677: 7654: 7490: 7481:
From this there is an associated long exact sequence
7397: 7368: 7345: 7300: 7280: 7249: 7121: 6961: 6932: 6912: 6892: 6868: 6836: 6812: 6269: 6116: 5882: 5759: 5631: 5544: 5488: 5444: 5390: 5348: 5278: 5234: 5207: 5159: 5132: 5095: 5052: 4957: 4909: 4840: 4785: 4718:. That interpretation can be made more explicit when 4492: 4322: 4160: 3531: 3401: 3362: 3306: 3241: 3137: 3089: 3047: 3004: 2940: 2880: 2832: 2782: 2760: 2568: 2354: 2316: 2188: 2090: 1960: 1844: 1787: 1738: 1549: 1404: 1345: 1191: 1071: 996: 960: 811: 604: 521: 491: 420: 219: 6602:
and think of sheaf cohomology as a functor from the
5032:{\displaystyle {\stackrel {\cong }{\to }}H^{j}(X,A)} 3498:-module in each degree. (No assumption is needed on 10706: 10670: 10556: 10477: 6580:, partly because of the importance of the sheaf of 6000:(not necessarily compact) determines an element of 5858:into a module over the singular cohomology ring of 5431:{\displaystyle \operatorname {Hom} (\pi _{1}(X),A)} 3788:The cohomology ring of the closed oriented surface 3181:could be replaced by any continuous deformation of 2157:{\displaystyle H^{*}(X,R)=\bigoplus _{i}H^{i}(X,R)} 478:{\displaystyle C_{i}^{*}:=\mathrm {Hom} (C_{i},A),} 159:is a powerful invariant in topology, associating a 10137: 9699:has the structure of a graded ring for each space 9691: 9623: 9584: 9548: 9509: 9455: 9411: 9366: 9321: 9274: 9183: 9023: 8892: 8606: 8446: 8313: 8102: 8046: 7784: 7660: 7637: 7470: 7380: 7354: 7324: 7286: 7266: 7232: 7101: 6944: 6918: 6898: 6874: 6851: 6818: 6350: 6244:-cycle with nonempty intersection will, if in the 6185: 5966: 5843: 5727: 5588: 5526: 5466: 5430: 5376: 5306: 5253: 5220: 5189: 5145: 5118: 5070: 5031: 4936: 4883: 4806: 4588: 4430: 4234: 3631: 3427: 3375: 3332: 3254: 3165: 3123: 3075: 3029: 2990: 2902: 2854: 2798: 2768: 2638: 2423: 2337: 2300: 2156: 2053: 1872: 1815: 1766: 1717: 1522: 1379: 1325: 1128: 1053: 978: 829: 731: 585: 504: 477: 331: 6391:related homology and differential forms, proving 6361:which (in retrospect) can be identified with the 5873:, the cap product gives the natural homomorphism 4722:is a smooth vector bundle over a smooth manifold 3839:of a point in degree 2. The product is given by: 3687:even and positive, because Poincaré duality with 1536:describes cohomology in terms of homology, using 586:{\displaystyle d_{i-1}:C_{i-1}^{*}\to C_{i}^{*}.} 3803:-module of the form: the element 1 in degree 0, 2862:can be thought of as represented by codimension- 358:on the set of continuous maps from the standard 2874:. For example, one way to define an element of 920:is sometimes not written. It is common to take 10140:History of Algebraic and Differential Topology 9895:, Proposition VIII.3.3 and Corollary VIII.3.4. 6228:of cycles on manifolds. On a closed oriented 2443:, then their cohomology rings are isomorphic. 2424:{\displaystyle f^{*}:H^{*}(Y,R)\to H^{*}(X,R)} 1140:from topological spaces to abelian groups (or 10455: 6618:to its abelian group of global sections over 5046:with the homotopy type of a CW complex. Here 2520:. As a result, a closed oriented submanifold 8: 5589:{\displaystyle 0\in H^{1}(X,\mathbb {Z} /2)} 2698:has an orientation, a closed submanifold of 1136:on cohomology. This makes cohomology into a 9049:) is the disjoint union of a set of pairs ( 8472:) is the disjoint union of a set of pairs ( 6469:In 1945, Eilenberg and Steenrod stated the 6455:(making cohomology into a graded ring) and 4830:for cohomology: there is a natural element 3969:containing 1/2, all odd-degree elements of 3931:. By graded-commutativity, it follows that 3731:is the same together with an extra copy of 3205:The cohomology ring of a point is the ring 2822:Very informally, for any topological space 10823: 10796: 10462: 10448: 10440: 10367:Algebraic Topology — Homology and Homotopy 10063: 7796:Axioms and generalized cohomology theories 6598:. The essential point is to fix the space 3961:= 0 for all odd-degree cohomology classes 1129:{\displaystyle f^{*}:H^{i}(Y)\to H^{i}(X)} 1054:{\displaystyle f_{*}:H_{i}(X)\to H_{i}(Y)} 10051: 9674: 9668: 9631:(complex connective K-theory), and so on. 9606: 9597: 9567: 9561: 9531: 9522: 9492: 9483: 9474:Various different flavors of topological 9435: 9426: 9391: 9379: 9349: 9340: 9301: 9296: 9290: 9254: 9249: 9243: 9172: 9159: 9146: 9136: 9108: 9102: 8994: 8982: 8973: 8952: 8946: 8854: 8840: 8825: 8813: 8804: 8789: 8777: 8768: 8747: 8735: 8583: 8567: 8554: 8541: 8531: 8525: 8423: 8411: 8402: 8375: 8369: 8281: 8267: 8246: 8234: 8225: 8210: 8198: 8189: 8174: 8162: 8059: 8003: 7767: 7745: 7723: 7698: 7682: 7676: 7653: 7608: 7586: 7561: 7545: 7523: 7501: 7489: 7419: 7398: 7396: 7367: 7344: 7313: 7309: 7308: 7299: 7279: 7257: 7256: 7248: 7213: 7194: 7173: 7154: 7141: 7140: 7137: 7128: 7120: 7093: 7089: 7088: 7079: 7075: 7074: 7072: 7056: 7044: 7040: 7039: 7024: 7016: 6999: 6987: 6983: 6982: 6966: 6960: 6931: 6911: 6891: 6867: 6843: 6839: 6838: 6835: 6811: 6318: 6296: 6274: 6268: 6156: 6142: 6121: 6115: 5931: 5915: 5887: 5881: 5820: 5792: 5764: 5758: 5698: 5670: 5642: 5630: 5575: 5571: 5570: 5555: 5543: 5534:classifies the double covering spaces of 5513: 5509: 5508: 5493: 5487: 5449: 5443: 5404: 5389: 5353: 5347: 5283: 5277: 5245: 5233: 5212: 5206: 5180: 5179: 5164: 5158: 5137: 5131: 5103: 5102: 5094: 5051: 5008: 4996: 4991: 4989: 4988: 4956: 4944:. More precisely, pulling back the class 4908: 4845: 4839: 4784: 4726:, since then a general smooth section of 4559: 4525: 4497: 4491: 4392: 4367: 4342: 4321: 4202: 4174: 4159: 3605: 3595: 3570: 3536: 3530: 3419: 3409: 3400: 3367: 3361: 3352:generators in degree 1. For example, let 3324: 3314: 3305: 3290:. In terms of Poincaré duality as above, 3246: 3240: 3142: 3136: 3100: 3088: 3052: 3046: 3009: 3003: 2973: 2945: 2939: 2885: 2879: 2837: 2831: 2788: 2784: 2783: 2781: 2762: 2761: 2759: 2612: 2567: 2400: 2372: 2359: 2353: 2315: 2274: 2240: 2211: 2187: 2133: 2123: 2095: 2089: 2021: 1993: 1965: 1959: 1849: 1843: 1792: 1786: 1743: 1737: 1693: 1692: 1677: 1661: 1660: 1659: 1631: 1608: 1607: 1583: 1567: 1562: 1561: 1560: 1548: 1487: 1465: 1443: 1415: 1403: 1350: 1344: 1296: 1268: 1246: 1224: 1202: 1190: 1111: 1089: 1076: 1070: 1036: 1014: 1001: 995: 959: 821: 816: 810: 717: 706: 686: 681: 676: 674: 673: 667: 662: 645: 640: 635: 633: 632: 626: 615: 603: 574: 569: 556: 545: 526: 520: 496: 490: 457: 439: 430: 425: 419: 311: 294: 289: 284: 282: 281: 275: 255: 250: 245: 243: 242: 230: 218: 8626:is a sequence of contravariant functors 6564:) coincide with singular cohomology for 3447:of the form: the element 1 in degree 0, 198:. Unlike more subtle invariants such as 10117: 10087: 10027: 10015: 10003: 9991: 9979: 9964: 9952: 9916: 9888: 9876: 9869: 5527:{\displaystyle H^{1}(X,\mathbb {Z} /2)} 4891:, and every cohomology class of degree 916:In what follows, the coefficient group 10333:A Concise Course in Algebraic Topology 9228:corresponding theory on CW complexes. 3506:gives that the cohomology ring of the 3294:is the class of a point on the sphere. 3041:; this is justified in that the class 885:, respectively, while elements of ker( 384:-th boundary homomorphism. The groups 89:in geometric situations: given spaces 5190:{\displaystyle H^{1}(X,\mathbb {Z} )} 2734:says that the singular cohomology of 7: 9940: 9928: 9904: 9892: 6540:. In particular, in the case of the 6201:Brief history of singular cohomology 6110:). The Poincaré duality isomorphism 4818:-th homotopy group is isomorphic to 3482:be any topological spaces such that 2469:, not necessarily compact (although 2439:. It follows that if two spaces are 46:is a general term for a sequence of 10075: 10039: 7325:{\displaystyle X(\mathbb {F} _{q})} 7112:If we have a scheme of finite type 4607:. In particular, the vector spaces 2991:{\displaystyle f^{*}()\in H^{i}(X)} 9907:, Propositions IV.8.12 and V.4.11. 9859:complex-oriented cohomology theory 8272: 6826:. Tools from Hodge theory, called 4171: 3777:is the class of a linear subspace 1725:A related statement is that for a 1580: 493: 446: 443: 440: 291: 252: 163:with any topological space. Every 25: 10405:Commentarii Mathematici Helvetici 10212:Foundations of Algebraic Topology 8516:) induce an isomorphism from the 6548:associated with an abelian group 6475:Foundations of Algebraic Topology 5119:{\displaystyle K(\mathbb {Z} ,1)} 4741:There are several other types of 4684:determines a cohomology class on 2706:determines a cohomology class on 2535:determines a cohomology class in 931:; then the cohomology groups are 10822: 10795: 10785: 10775: 10764: 10754: 10753: 10547: 9322:{\displaystyle \pi _{*}^{S}(X).} 9275:{\displaystyle \pi _{S}^{*}(X).} 8103:{\displaystyle g:(X,A)\to (Y,B)} 8047:{\displaystyle f:(X,A)\to (Y,B)} 6852:{\displaystyle \mathbb {P} ^{n}} 6248:, have as their intersection a ( 6062:) can be computed by perturbing 3993:, as one sees in the example of 2654:is a submanifold of codimension 2639:{\displaystyle =\in H^{i+j}(X),} 2550:are submanifolds of codimension 939:. A standard choice is the ring 50:, usually one associated with a 9093:) induce an isomorphism to the 7267:{\displaystyle X(\mathbb {C} )} 5854:makes the singular homology of 4884:{\displaystyle H^{j}(K(A,j),A)} 4459:oriented manifold of dimension 3679:; this makes sense even though 3494:) is a finitely generated free 3474:be a commutative ring, and let 3213:space, such as Euclidean space 2338:{\displaystyle f\colon X\to Y,} 2229: 10175:Lectures on Algebraic Topology 9686: 9680: 9618: 9612: 9579: 9573: 9543: 9537: 9504: 9498: 9447: 9441: 9403: 9397: 9361: 9355: 9313: 9307: 9266: 9260: 9178: 9152: 9129: 9126: 9114: 9018: 9000: 8975: 8970: 8958: 8881: 8878: 8866: 8842: 8837: 8831: 8806: 8801: 8795: 8770: 8765: 8753: 8740: 8601: 8589: 8576: 8573: 8547: 8441: 8429: 8404: 8399: 8381: 8302: 8299: 8293: 8269: 8264: 8252: 8227: 8222: 8216: 8191: 8186: 8180: 8167: 8097: 8085: 8082: 8079: 8067: 8041: 8029: 8026: 8023: 8011: 7779: 7773: 7757: 7751: 7735: 7729: 7713: 7710: 7704: 7688: 7629: 7626: 7620: 7601: 7598: 7592: 7579: 7576: 7573: 7567: 7551: 7535: 7529: 7516: 7513: 7507: 7494: 7456: 7444: 7438: 7431: 7425: 7407: 7319: 7304: 7261: 7253: 7065: 7062: 7049: 7030: 6993: 6972: 6342: 6336: 6311: 6308: 6302: 6286: 6280: 6180: 6168: 6144: 6139: 6127: 5958: 5949: 5937: 5924: 5908: 5905: 5893: 5838: 5826: 5813: 5810: 5798: 5782: 5770: 5722: 5710: 5691: 5688: 5676: 5660: 5648: 5583: 5561: 5521: 5499: 5461: 5455: 5425: 5416: 5410: 5397: 5371: 5359: 5301: 5289: 5238: 5197:is pulled back from the class 5184: 5170: 5113: 5099: 5065: 5053: 5026: 5014: 4992: 4985: 4982: 4970: 4958: 4931: 4919: 4913: 4878: 4869: 4857: 4851: 4801: 4789: 4577: 4565: 4552: 4549: 4537: 4515: 4503: 4422: 4404: 4382: 4379: 4373: 4360: 4357: 4354: 4348: 4335: 4226: 4214: 4192: 4180: 4122:). The cup product of classes 3623: 3611: 3588: 3576: 3560: 3542: 3416: 3402: 3321: 3307: 3160: 3157: 3151: 3148: 3115: 3109: 3070: 3067: 3061: 3058: 3024: 3018: 2985: 2979: 2963: 2960: 2954: 2951: 2897: 2891: 2849: 2843: 2799:{\displaystyle \mathbb {Z} /p} 2630: 2624: 2602: 2590: 2584: 2578: 2575: 2569: 2461:means a submanifold that is a 2418: 2406: 2393: 2390: 2378: 2326: 2292: 2280: 2258: 2246: 2208: 2198: 2151: 2139: 2113: 2101: 2045: 2033: 2014: 2011: 1999: 1983: 1971: 1867: 1855: 1810: 1798: 1761: 1749: 1709: 1706: 1697: 1683: 1670: 1652: 1649: 1637: 1624: 1621: 1612: 1598: 1576: 1553: 1514: 1511: 1499: 1480: 1477: 1471: 1458: 1455: 1449: 1436: 1433: 1421: 1408: 1374: 1356: 1317: 1314: 1308: 1289: 1286: 1274: 1261: 1258: 1252: 1236: 1230: 1217: 1214: 1208: 1195: 1123: 1117: 1104: 1101: 1095: 1048: 1042: 1029: 1026: 1020: 970: 723: 677: 636: 608: 562: 469: 450: 323: 285: 246: 223: 1: 9592:(complex periodic K-theory), 9331:Various different flavors of 8909:is the union of subcomplexes 8624:generalized cohomology theory 8332:is the union of subcomplexes 3965:. It follows that for a ring 3765:is the class of a hyperplane 3467:= −, by graded-commutativity. 3395:) in the 2-dimensional torus 3356:denote a point in the circle 3232:, the cohomology ring of the 1838:, then the cohomology groups 1534:universal coefficient theorem 505:{\displaystyle \partial _{i}} 9556:(real connective K-theory), 7814:Alexander–Spanier cohomology 7388:there is a Cartesian square 6524:, one has cohomology groups 6493:Alexander–Spanier cohomology 6440:by dualizing Čech homology. 5977:which is an isomorphism for 3201:, unless stated otherwise. 3124:{\displaystyle X-f^{-1}(N).} 2910:is to give a continuous map 2769:{\displaystyle \mathbb {Z} } 2473:is automatically compact if 2431:is a homomorphism of graded 1380:{\displaystyle H^{i}(X,Y;A)} 182:from the cohomology ring of 97:, and some kind of function 10341:University of Chicago Press 10314:Encyclopedia of Mathematics 9412:{\displaystyle MSO^{*}(X),} 7873:generalized homology theory 7804:List of cohomology theories 6945:{\displaystyle \ell \neq p} 6081:A closed oriented manifold 5467:{\displaystyle \pi _{1}(X)} 5342:connected, it follows that 4937:{\displaystyle X\to K(A,j)} 3835:in degree 1, and the class 3711:/2 spanned by the elements 3455: := in degree 1, and 3428:{\displaystyle (S^{1})^{2}} 3333:{\displaystyle (S^{1})^{n}} 3297:The cohomology ring of the 2702:with an orientation on its 10865: 10716:Banach fixed-point theorem 10284:Cambridge University Press 10216:Princeton University Press 9517:(real periodic K-theory), 9456:{\displaystyle MU^{*}(X),} 7801: 7381:{\displaystyle Z\subset X} 6638:of the left exact functor 6502: 6484:defined sheaf cohomology. 6012:), and a compact oriented 5614:For any topological space 5607: 5377:{\displaystyle H^{1}(X,A)} 5307:{\displaystyle H^{1}(X,A)} 5254:{\displaystyle X\to S^{1}} 4764: 4730:vanishes on a codimension- 4662: 4651:is a perfect pairing over 4444: 4050:). Namely, for any spaces 3799:≥ 0 has a basis as a free 3435:. Then the cohomology of ( 1873:{\displaystyle H^{i}(X,A)} 1816:{\displaystyle H_{i}(X,F)} 1767:{\displaystyle H^{i}(X,F)} 805:negative. The elements of 10749: 10545: 9756:Coherent sheaf cohomology 9721:Other cohomology theories 9635:Brown–Peterson cohomology 9624:{\displaystyle ku^{*}(X)} 9549:{\displaystyle ko^{*}(X)} 9510:{\displaystyle KO^{*}(X)} 9367:{\displaystyle MO^{*}(X)} 9225:weak homotopy equivalence 8941:) induces an isomorphism 8364:) induces an isomorphism 7822:Eilenberg–Steenrod axioms 6041:). The cap product ∩ ∈ 6024:determines an element of 6016:-dimensional submanifold 5746:and any commutative ring 4680:over a topological space 3030:{\displaystyle f^{-1}(N)} 2998:as lying on the subspace 2922:and a closed codimension- 2081:. This product makes the 830:{\displaystyle C_{i}^{*}} 404:, and replace each group 400:Now fix an abelian group 126:gives rise to a function 10365:Switzer, Robert (1975), 9736:André–Quillen cohomology 9692:{\displaystyle E^{*}(X)} 9585:{\displaystyle K^{*}(X)} 9067:), then the inclusions ( 8490:), then the inclusions ( 7851:is a single point, then 7334:Weil cohomology theories 6712:-modules. Likewise, the 6421:At a 1935 conference in 4761:Eilenberg–MacLane spaces 4058:with cohomology classes 3744:complex projective space 2903:{\displaystyle H^{i}(X)} 2870:that can move freely on 2855:{\displaystyle H^{i}(X)} 979:{\displaystyle f:X\to Y} 205:For a topological space 9816:Intersection cohomology 6801:Cohomology of varieties 6767:) is isomorphic to Ext( 6751:on a topological space 6552:, the resulting groups 6520:on a topological space 5268:, say for a CW complex 5089:For example, the space 4903:by some continuous map 4824:Eilenberg–MacLane space 4771:For each abelian group 4767:Eilenberg–MacLane space 4751:Stiefel–Whitney classes 3742:The cohomology ring of 3641:The cohomology ring of 3228:For a positive integer 3166:{\displaystyle f^{*}()} 3076:{\displaystyle f^{*}()} 2646:where the intersection 2310:For any continuous map 1164:Mayer–Vietoris sequence 161:graded-commutative ring 54:, often defined from a 10771:Mathematics portal 10671:Metrics and properties 10657:Second-countable space 9841:Non-abelian cohomology 9826:Lie algebra cohomology 9776:Equivariant cohomology 9761:Crystalline cohomology 9693: 9625: 9586: 9550: 9511: 9457: 9413: 9368: 9323: 9284:stable homotopy groups 9276: 9185: 9025: 8894: 8681:,∅)). The axioms are: 8608: 8448: 8315: 8104: 8048: 7991:,∅)). The axioms are: 7917:natural transformation 7840:for smooth manifolds. 7836:for CW complexes, and 7786: 7662: 7639: 7472: 7382: 7356: 7355:{\displaystyle \geq 2} 7326: 7288: 7268: 7234: 7103: 6946: 6920: 6900: 6876: 6853: 6820: 6352: 6232:-dimensional manifold 6187: 5968: 5845: 5729: 5590: 5528: 5468: 5432: 5378: 5308: 5255: 5222: 5191: 5147: 5120: 5072: 5033: 4938: 4885: 4808: 4807:{\displaystyle K(A,j)} 4743:characteristic classes 4659:Characteristic classes 4590: 4432: 4236: 3683:is not orientable for 3633: 3429: 3377: 3334: 3256: 3226: 3167: 3125: 3077: 3031: 2992: 2904: 2856: 2800: 2770: 2726:For a smooth manifold 2640: 2489:manifold of dimension 2425: 2339: 2302: 2158: 2055: 1874: 1817: 1768: 1719: 1524: 1381: 1327: 1130: 1055: 980: 831: 733: 587: 506: 479: 333: 211:singular chain complex 9811:Hochschild cohomology 9694: 9626: 9587: 9551: 9512: 9458: 9414: 9369: 9324: 9277: 9186: 9026: 8917:, then the inclusion 8895: 8663:boundary homomorphism 8609: 8449: 8340:, then the inclusion 8316: 8105: 8049: 7977:) is a shorthand for 7961:boundary homomorphism 7826:simplicial cohomology 7787: 7663: 7640: 7473: 7383: 7357: 7327: 7289: 7287:{\displaystyle \ell } 7269: 7235: 7104: 6952:. This is defined as 6947: 6926:-adic cohomology for 6921: 6919:{\displaystyle \ell } 6901: 6877: 6854: 6821: 6586:holomorphic functions 6406:theorem; a result on 6365:on the cohomology of 6353: 6188: 5969: 5846: 5730: 5591: 5529: 5469: 5433: 5379: 5309: 5256: 5223: 5221:{\displaystyle S^{1}} 5192: 5148: 5146:{\displaystyle S^{1}} 5121: 5073: 5034: 4939: 4886: 4809: 4591: 4433: 4237: 3643:real projective space 3634: 3430: 3378: 3376:{\displaystyle S^{1}} 3335: 3257: 3255:{\displaystyle S^{n}} 3224: 3168: 3131:The cohomology class 3126: 3078: 3032: 2993: 2905: 2857: 2801: 2771: 2641: 2497:gives an isomorphism 2426: 2340: 2303: 2159: 2056: 1940:and commutative ring 1875: 1818: 1769: 1720: 1540:. Namely, there is a 1525: 1382: 1328: 1138:contravariant functor 1131: 1056: 981: 845:with coefficients in 832: 760:is defined to be ker( 756:with coefficients in 734: 588: 507: 480: 334: 144:, which gives them a 10726:Invariance of domain 10678:Euler characteristic 10652:Bundle (mathematics) 9667: 9655:A cohomology theory 9596: 9560: 9521: 9482: 9425: 9378: 9339: 9289: 9242: 9101: 8945: 8734: 8524: 8368: 8161: 8058: 8002: 7911:is a CW complex and 7830:simplicial complexes 7675: 7652: 7488: 7395: 7366: 7343: 7298: 7294:-adic cohomology of 7278: 7247: 7119: 6959: 6930: 6910: 6890: 6866: 6834: 6810: 6376:-cochain on a space 6267: 6114: 5880: 5757: 5750:. The resulting map 5629: 5542: 5486: 5442: 5388: 5346: 5276: 5232: 5205: 5157: 5130: 5093: 5050: 4955: 4907: 4838: 4783: 4665:Characteristic class 4490: 4320: 4158: 4001:/2 coefficients) or 3529: 3470:More generally, let 3399: 3360: 3304: 3239: 3135: 3087: 3045: 3002: 2938: 2878: 2830: 2780: 2758: 2566: 2352: 2314: 2186: 2088: 1958: 1842: 1785: 1736: 1547: 1542:short exact sequence 1402: 1343: 1189: 1069: 994: 958: 849:. (Equivalently, an 809: 602: 519: 489: 418: 217: 66:in homology theory. 10849:Cohomology theories 10736:Tychonoff's theorem 10731:Poincaré conjecture 10485:General (point-set) 10030:, Proposition 3.38. 9646:elliptic cohomology 9644:Various flavors of 9467:, via a theorem of 9374:oriented cobordism 9306: 9259: 7865:George W. Whitehead 7834:cellular cohomology 7029: 6669:to abelian groups. 6630:). This functor is 6596:homological algebra 6443:From 1936 to 1938, 6256: −  6226:intersection theory 6207:dual cell structure 5538:, with the element 4899:is the pullback of 4779:, there is a space 4775:and natural number 4479:) is isomorphic to 4098:) cohomology class 3652:/2 coefficients is 3439:) has a basis as a 3173:can move freely on 2812:Steenrod operations 2806:for a prime number 2441:homotopy equivalent 2182:in the sense that: 1572: 1337:relative cohomology 1183:long exact sequence 911:equivalence classes 869:.) Elements of ker( 826: 722: 672: 631: 579: 561: 435: 339:By definition, the 157:Singular cohomology 152:Singular cohomology 122:, composition with 10721:De Rham cohomology 10642:Polyhedral complex 10632:Simplicial complex 10418:10.1007/BF02566923 10279:Algebraic Topology 10245:Algebraic Geometry 9846:Quantum cohomology 9836:Motivic cohomology 9771:Deligne cohomology 9741:Bounded cohomology 9731:Algebraic K-theory 9689: 9621: 9582: 9546: 9507: 9453: 9409: 9364: 9319: 9292: 9272: 9245: 9181: 9141: 9021: 8890: 8604: 8536: 8444: 8311: 8100: 8044: 7863:≠ 0. Around 1960, 7838:de Rham cohomology 7782: 7658: 7648:If the subvariety 7635: 7468: 7466: 7378: 7352: 7322: 7284: 7264: 7230: 7099: 7012: 7007: 6942: 6916: 6906:one can construct 6896: 6872: 6849: 6816: 6574:algebraic geometry 6516:of abelian groups 6414:in terms of group 6408:topological groups 6404:Pontryagin duality 6348: 6183: 5964: 5841: 5725: 5622:is a bilinear map 5586: 5524: 5464: 5428: 5374: 5304: 5251: 5218: 5187: 5143: 5116: 5068: 5029: 4948:gives a bijection 4934: 4881: 4804: 4755:Pontryagin classes 4586: 4483:, and the product 4428: 4232: 3773:. More generally, 3761:in degree 2. Here 3668:is the class of a 3664:in degree 1. Here 3629: 3425: 3373: 3330: 3252: 3227: 3177:in the sense that 3163: 3121: 3073: 3027: 2988: 2900: 2852: 2796: 2766: 2748:differential forms 2636: 2452:closed submanifold 2421: 2335: 2298: 2180:graded-commutative 2154: 2128: 2051: 1926:finitely generated 1870: 1813: 1764: 1715: 1556: 1520: 1377: 1323: 1181:, then there is a 1126: 1061:on homology and a 1051: 976: 909:(because they are 907:cohomology classes 827: 812: 729: 702: 658: 611: 583: 565: 541: 502: 475: 421: 366:(called "singular 356:free abelian group 329: 69:From its start in 40:algebraic topology 34:, specifically in 10836: 10835: 10625:fundamental group 10241:Hartshorne, Robin 10204:Eilenberg, Samuel 10188:978-3-540-58660-9 9931:, pp. 62–63. 9821:Khovanov homology 9801:Galois cohomology 9766:Cyclic cohomology 9420:complex cobordism 9237:cohomotopy groups 9132: 8988: 8848: 8819: 8783: 8527: 8417: 8275: 8240: 8204: 7875:is a sequence of 7871:By definition, a 7661:{\displaystyle Z} 7224: 7131: 7000: 6899:{\displaystyle p} 6875:{\displaystyle p} 6819:{\displaystyle 0} 6582:regular functions 6427:Andrey Kolmogorov 6412:Alexander duality 6393:de Rham's theorem 6222:Solomon Lefschetz 6150: 6091:fundamental class 5984:For example, let 5738:for any integers 5476:fundamental group 5384:is isomorphic to 5001: 4828:classifying space 4669:An oriented real 4603:for each integer 4467:be a field. Then 2732:de Rham's theorem 2674:. In the case of 2119: 1904:is a commutative 1884:greater than the 1830:is a topological 1774:is precisely the 954:A continuous map 777:) and denoted by 699: 657: 652: 514:dual homomorphism 341:singular homology 306: 301: 268: 52:topological space 16:(Redirected from 10856: 10826: 10825: 10799: 10798: 10789: 10779: 10769: 10768: 10757: 10756: 10551: 10464: 10457: 10450: 10441: 10436: 10391: 10361: 10338: 10322: 10304: 10269: 10236: 10208:Steenrod, Norman 10199: 10166: 10143: 10121: 10115: 10109: 10108: 10097: 10091: 10085: 10079: 10073: 10067: 10066:, Section III.2. 10061: 10055: 10049: 10043: 10037: 10031: 10025: 10019: 10013: 10007: 10001: 9995: 9989: 9983: 9977: 9968: 9962: 9956: 9950: 9944: 9943:, Theorem II.29. 9938: 9932: 9926: 9920: 9914: 9908: 9902: 9896: 9886: 9880: 9874: 9831:Local cohomology 9806:Group cohomology 9781:Étale cohomology 9698: 9696: 9695: 9690: 9679: 9678: 9630: 9628: 9627: 9622: 9611: 9610: 9591: 9589: 9588: 9583: 9572: 9571: 9555: 9553: 9552: 9547: 9536: 9535: 9516: 9514: 9513: 9508: 9497: 9496: 9462: 9460: 9459: 9454: 9440: 9439: 9418: 9416: 9415: 9410: 9396: 9395: 9373: 9371: 9370: 9365: 9354: 9353: 9328: 9326: 9325: 9320: 9305: 9300: 9281: 9279: 9278: 9273: 9258: 9253: 9190: 9188: 9187: 9182: 9177: 9176: 9164: 9163: 9151: 9150: 9140: 9113: 9112: 9030: 9028: 9027: 9022: 8999: 8998: 8989: 8987: 8986: 8974: 8957: 8956: 8899: 8897: 8896: 8891: 8865: 8864: 8849: 8841: 8830: 8829: 8820: 8818: 8817: 8805: 8794: 8793: 8784: 8782: 8781: 8769: 8752: 8751: 8660: 8613: 8611: 8610: 8605: 8588: 8587: 8572: 8571: 8559: 8558: 8546: 8545: 8535: 8453: 8451: 8450: 8445: 8428: 8427: 8418: 8416: 8415: 8403: 8380: 8379: 8320: 8318: 8317: 8312: 8292: 8291: 8276: 8268: 8251: 8250: 8241: 8239: 8238: 8226: 8215: 8214: 8205: 8203: 8202: 8190: 8179: 8178: 8156: 8137: 8109: 8107: 8106: 8101: 8054:is homotopic to 8053: 8051: 8050: 8045: 7958: 7818:sheaf cohomology 7791: 7789: 7788: 7783: 7772: 7771: 7750: 7749: 7728: 7727: 7703: 7702: 7687: 7686: 7667: 7665: 7664: 7659: 7644: 7642: 7641: 7636: 7619: 7618: 7591: 7590: 7566: 7565: 7550: 7549: 7528: 7527: 7506: 7505: 7477: 7475: 7474: 7469: 7467: 7442: 7424: 7423: 7387: 7385: 7384: 7379: 7361: 7359: 7358: 7353: 7331: 7329: 7328: 7323: 7318: 7317: 7312: 7293: 7291: 7290: 7285: 7273: 7271: 7270: 7265: 7260: 7239: 7237: 7236: 7231: 7229: 7225: 7223: 7219: 7218: 7217: 7199: 7198: 7184: 7183: 7179: 7178: 7177: 7159: 7158: 7144: 7138: 7132: 7129: 7108: 7106: 7105: 7100: 7098: 7097: 7092: 7086: 7085: 7084: 7083: 7078: 7061: 7060: 7048: 7043: 7028: 7023: 7008: 6992: 6991: 6986: 6971: 6970: 6951: 6949: 6948: 6943: 6925: 6923: 6922: 6917: 6905: 6903: 6902: 6897: 6881: 6879: 6878: 6873: 6858: 6856: 6855: 6850: 6848: 6847: 6842: 6828:Hodge structures 6825: 6823: 6822: 6817: 6663:derived category 6636:derived functors 6604:abelian category 6584:or the sheaf of 6578:complex analysis 6510:Sheaf cohomology 6505:Sheaf cohomology 6499:Sheaf cohomology 6464:Samuel Eilenberg 6357: 6355: 6354: 6349: 6335: 6334: 6301: 6300: 6279: 6278: 6246:general position 6192: 6190: 6189: 6184: 6167: 6166: 6151: 6143: 6126: 6125: 5973: 5971: 5970: 5965: 5936: 5935: 5920: 5919: 5892: 5891: 5850: 5848: 5847: 5842: 5825: 5824: 5797: 5796: 5769: 5768: 5734: 5732: 5731: 5726: 5709: 5708: 5675: 5674: 5647: 5646: 5595: 5593: 5592: 5587: 5579: 5574: 5560: 5559: 5533: 5531: 5530: 5525: 5517: 5512: 5498: 5497: 5473: 5471: 5470: 5465: 5454: 5453: 5437: 5435: 5434: 5429: 5409: 5408: 5383: 5381: 5380: 5375: 5358: 5357: 5313: 5311: 5310: 5305: 5288: 5287: 5260: 5258: 5257: 5252: 5250: 5249: 5227: 5225: 5224: 5219: 5217: 5216: 5196: 5194: 5193: 5188: 5183: 5169: 5168: 5152: 5150: 5149: 5144: 5142: 5141: 5125: 5123: 5122: 5117: 5106: 5077: 5075: 5074: 5071:{\displaystyle } 5069: 5042:for every space 5038: 5036: 5035: 5030: 5013: 5012: 5003: 5002: 5000: 4995: 4990: 4943: 4941: 4940: 4935: 4890: 4888: 4887: 4882: 4850: 4849: 4813: 4811: 4810: 4805: 4595: 4593: 4592: 4587: 4564: 4563: 4536: 4535: 4502: 4501: 4447:Poincaré duality 4441:Poincaré duality 4437: 4435: 4434: 4429: 4403: 4402: 4372: 4371: 4347: 4346: 4241: 4239: 4238: 4233: 4213: 4212: 4179: 4178: 4092:external product 3953: 3638: 3636: 3635: 3630: 3610: 3609: 3600: 3599: 3575: 3574: 3541: 3540: 3434: 3432: 3431: 3426: 3424: 3423: 3414: 3413: 3382: 3380: 3379: 3374: 3372: 3371: 3342:exterior algebra 3339: 3337: 3336: 3331: 3329: 3328: 3319: 3318: 3261: 3259: 3258: 3253: 3251: 3250: 3172: 3170: 3169: 3164: 3147: 3146: 3130: 3128: 3127: 3122: 3108: 3107: 3082: 3080: 3079: 3074: 3057: 3056: 3036: 3034: 3033: 3028: 3017: 3016: 2997: 2995: 2994: 2989: 2978: 2977: 2950: 2949: 2909: 2907: 2906: 2901: 2890: 2889: 2861: 2859: 2858: 2853: 2842: 2841: 2805: 2803: 2802: 2797: 2792: 2787: 2775: 2773: 2772: 2767: 2765: 2746:, defined using 2676:smooth manifolds 2645: 2643: 2642: 2637: 2623: 2622: 2495:Poincaré duality 2430: 2428: 2427: 2422: 2405: 2404: 2377: 2376: 2364: 2363: 2344: 2342: 2341: 2336: 2307: 2305: 2304: 2299: 2279: 2278: 2245: 2244: 2219: 2218: 2163: 2161: 2160: 2155: 2138: 2137: 2127: 2100: 2099: 2060: 2058: 2057: 2052: 2032: 2031: 1998: 1997: 1970: 1969: 1879: 1877: 1876: 1871: 1854: 1853: 1822: 1820: 1819: 1814: 1797: 1796: 1773: 1771: 1770: 1765: 1748: 1747: 1724: 1722: 1721: 1716: 1696: 1682: 1681: 1666: 1665: 1664: 1636: 1635: 1611: 1594: 1593: 1571: 1566: 1565: 1529: 1527: 1526: 1521: 1498: 1497: 1470: 1469: 1448: 1447: 1420: 1419: 1386: 1384: 1383: 1378: 1355: 1354: 1332: 1330: 1329: 1324: 1307: 1306: 1273: 1272: 1251: 1250: 1229: 1228: 1207: 1206: 1170:is the union of 1135: 1133: 1132: 1127: 1116: 1115: 1094: 1093: 1081: 1080: 1060: 1058: 1057: 1052: 1041: 1040: 1019: 1018: 1006: 1005: 985: 983: 982: 977: 926:commutative ring 836: 834: 833: 828: 825: 820: 750:cohomology group 738: 736: 735: 730: 721: 716: 701: 700: 698: 697: 696: 680: 675: 671: 666: 655: 654: 653: 651: 650: 649: 639: 634: 630: 625: 592: 590: 589: 584: 578: 573: 560: 555: 537: 536: 511: 509: 508: 503: 501: 500: 484: 482: 481: 476: 462: 461: 449: 434: 429: 338: 336: 335: 330: 322: 321: 304: 303: 302: 300: 299: 298: 288: 283: 280: 279: 270: 269: 267: 266: 265: 249: 244: 241: 240: 135: 121: 62:on the group of 21: 18:Cohomology class 10864: 10863: 10859: 10858: 10857: 10855: 10854: 10853: 10839: 10838: 10837: 10832: 10763: 10745: 10741:Urysohn's lemma 10702: 10666: 10552: 10543: 10515:low-dimensional 10473: 10468: 10394: 10381: 10371:Springer-Verlag 10364: 10351: 10336: 10326: 10307: 10294: 10272: 10259: 10249:Springer-Verlag 10239: 10226: 10202: 10189: 10179:Springer-Verlag 10169: 10156: 10134:Dieudonné, Jean 10132: 10129: 10124: 10116: 10112: 10099: 10098: 10094: 10086: 10082: 10074: 10070: 10064:Hartshorne 1977 10062: 10058: 10054:, Section IV.3. 10050: 10046: 10038: 10034: 10026: 10022: 10014: 10010: 10002: 9998: 9990: 9986: 9982:, Theorem 3.19. 9978: 9971: 9967:, Theorem 3.15. 9963: 9959: 9955:, Example 3.16. 9951: 9947: 9939: 9935: 9927: 9923: 9919:, Theorem 3.11. 9915: 9911: 9903: 9899: 9891:, Theorem 3.5; 9887: 9883: 9875: 9871: 9867: 9855: 9850: 9791:Flat cohomology 9751:Čech cohomology 9746:BRST cohomology 9723: 9714: 9670: 9665: 9664: 9639:Morava K-theory 9602: 9594: 9593: 9563: 9558: 9557: 9527: 9519: 9518: 9488: 9480: 9479: 9431: 9423: 9422: 9387: 9376: 9375: 9345: 9337: 9336: 9287: 9286: 9240: 9239: 9168: 9155: 9142: 9104: 9099: 9098: 9084: 9075: 9066: 9057: 8990: 8978: 8948: 8943: 8942: 8850: 8821: 8809: 8785: 8773: 8743: 8732: 8731: 8635: 8579: 8563: 8550: 8537: 8522: 8521: 8507: 8498: 8489: 8480: 8419: 8407: 8371: 8366: 8365: 8277: 8242: 8230: 8206: 8194: 8170: 8159: 8158: 8139: 8125: 8056: 8055: 8000: 7999: 7986: 7972: 7952: 7934: 7925: 7919: 7886: 7845:dimension axiom 7810:Čech cohomology 7806: 7798: 7763: 7741: 7719: 7694: 7678: 7673: 7672: 7650: 7649: 7604: 7582: 7557: 7541: 7519: 7497: 7486: 7485: 7465: 7464: 7459: 7454: 7448: 7447: 7441: 7435: 7434: 7415: 7410: 7405: 7393: 7392: 7364: 7363: 7341: 7340: 7307: 7296: 7295: 7276: 7275: 7245: 7244: 7209: 7190: 7189: 7185: 7169: 7150: 7149: 7145: 7139: 7133: 7117: 7116: 7087: 7073: 7068: 7052: 6981: 6962: 6957: 6956: 6928: 6927: 6908: 6907: 6888: 6887: 6864: 6863: 6837: 6832: 6831: 6808: 6807: 6803: 6788: 6775: 6735: 6721: 6704: 6686: 6659:hypercohomology 6536:) for integers 6507: 6501: 6445:Hassler Whitney 6438:Čech cohomology 6434:Norman Steenrod 6389:Georges de Rham 6314: 6292: 6270: 6265: 6264: 6218:J. W. Alexander 6203: 6152: 6117: 6112: 6111: 6101: 6053: 6032: 5927: 5911: 5883: 5878: 5877: 5816: 5788: 5760: 5755: 5754: 5694: 5666: 5638: 5627: 5626: 5612: 5606: 5551: 5540: 5539: 5489: 5484: 5483: 5482:. For example, 5445: 5440: 5439: 5400: 5386: 5385: 5349: 5344: 5343: 5316:covering spaces 5279: 5274: 5273: 5241: 5230: 5229: 5208: 5203: 5202: 5160: 5155: 5154: 5133: 5128: 5127: 5091: 5090: 5048: 5047: 5004: 4953: 4952: 4905: 4904: 4895:on every space 4841: 4836: 4835: 4781: 4780: 4769: 4763: 4734:submanifold of 4667: 4661: 4635:with values in 4601:perfect pairing 4555: 4521: 4493: 4488: 4487: 4449: 4443: 4388: 4363: 4338: 4318: 4317: 4198: 4170: 4156: 4155: 4090:), there is an 4020: 3948: 3940: 3932: 3922: 3914: 3897: 3889: 3872: 3864: 3855: 3847: 3834: 3825: 3818: 3809: 3727:-cohomology of 3699:has an element 3695:-cohomology of 3601: 3591: 3566: 3532: 3527: 3526: 3504:Künneth formula 3415: 3405: 3397: 3396: 3363: 3358: 3357: 3320: 3310: 3302: 3301: 3276:polynomial ring 3242: 3237: 3236: 3195: 3138: 3133: 3132: 3096: 3085: 3084: 3048: 3043: 3042: 3005: 3000: 2999: 2969: 2941: 2936: 2935: 2881: 2876: 2875: 2833: 2828: 2827: 2778: 2777: 2756: 2755: 2608: 2564: 2563: 2558:that intersect 2516: 2448:closed manifold 2396: 2368: 2355: 2350: 2349: 2312: 2311: 2270: 2236: 2207: 2184: 2183: 2171:cohomology ring 2129: 2091: 2086: 2085: 2017: 1989: 1961: 1956: 1955: 1906:Noetherian ring 1845: 1840: 1839: 1788: 1783: 1782: 1739: 1734: 1733: 1673: 1655: 1627: 1579: 1545: 1544: 1483: 1461: 1439: 1411: 1400: 1399: 1346: 1341: 1340: 1292: 1264: 1242: 1220: 1198: 1187: 1186: 1107: 1085: 1072: 1067: 1066: 1032: 1010: 997: 992: 991: 956: 955: 807: 806: 776: 765: 741:For an integer 682: 641: 600: 599: 597:cochain complex 522: 517: 516: 492: 487: 486: 453: 416: 415: 409: 392: 379: 352: 307: 290: 271: 251: 226: 215: 214: 200:homotopy groups 154: 127: 109: 56:cochain complex 36:homology theory 28: 23: 22: 15: 12: 11: 5: 10862: 10860: 10852: 10851: 10841: 10840: 10834: 10833: 10831: 10830: 10820: 10819: 10818: 10813: 10808: 10793: 10783: 10773: 10761: 10750: 10747: 10746: 10744: 10743: 10738: 10733: 10728: 10723: 10718: 10712: 10710: 10704: 10703: 10701: 10700: 10695: 10690: 10688:Winding number 10685: 10680: 10674: 10672: 10668: 10667: 10665: 10664: 10659: 10654: 10649: 10644: 10639: 10634: 10629: 10628: 10627: 10622: 10620:homotopy group 10612: 10611: 10610: 10605: 10600: 10595: 10590: 10580: 10575: 10570: 10560: 10558: 10554: 10553: 10546: 10544: 10542: 10541: 10536: 10531: 10530: 10529: 10519: 10518: 10517: 10507: 10502: 10497: 10492: 10487: 10481: 10479: 10475: 10474: 10469: 10467: 10466: 10459: 10452: 10444: 10438: 10437: 10392: 10379: 10362: 10349: 10324: 10305: 10292: 10274:Hatcher, Allen 10270: 10257: 10237: 10224: 10200: 10187: 10171:Dold, Albrecht 10167: 10154: 10128: 10125: 10123: 10122: 10110: 10092: 10080: 10068: 10056: 10052:Dieudonné 1989 10044: 10042:, p. 177. 10032: 10020: 10018:, p. 186. 10008: 10006:, Example 3.7. 9996: 9994:, p. 222. 9984: 9969: 9957: 9945: 9933: 9921: 9909: 9897: 9889:Hatcher (2001) 9881: 9879:, p. 108. 9868: 9866: 9863: 9862: 9861: 9854: 9851: 9849: 9848: 9843: 9838: 9833: 9828: 9823: 9818: 9813: 9808: 9803: 9798: 9796:Floer homology 9793: 9788: 9783: 9778: 9773: 9768: 9763: 9758: 9753: 9748: 9743: 9738: 9733: 9727: 9722: 9719: 9712: 9688: 9685: 9682: 9677: 9673: 9661:multiplicative 9659:is said to be 9650: 9649: 9642: 9632: 9620: 9617: 9614: 9609: 9605: 9601: 9581: 9578: 9575: 9570: 9566: 9545: 9542: 9539: 9534: 9530: 9526: 9506: 9503: 9500: 9495: 9491: 9487: 9472: 9469:Daniel Quillen 9452: 9449: 9446: 9443: 9438: 9434: 9430: 9408: 9405: 9402: 9399: 9394: 9390: 9386: 9383: 9363: 9360: 9357: 9352: 9348: 9344: 9329: 9318: 9315: 9312: 9309: 9304: 9299: 9295: 9271: 9268: 9265: 9262: 9257: 9252: 9248: 9197: 9196: 9180: 9175: 9171: 9167: 9162: 9158: 9154: 9149: 9145: 9139: 9135: 9131: 9128: 9125: 9122: 9119: 9116: 9111: 9107: 9080: 9071: 9062: 9053: 9036: 9020: 9017: 9014: 9011: 9008: 9005: 9002: 8997: 8993: 8985: 8981: 8977: 8972: 8969: 8966: 8963: 8960: 8955: 8951: 8900: 8889: 8886: 8883: 8880: 8877: 8874: 8871: 8868: 8863: 8860: 8857: 8853: 8847: 8844: 8839: 8836: 8833: 8828: 8824: 8816: 8812: 8808: 8803: 8800: 8797: 8792: 8788: 8780: 8776: 8772: 8767: 8764: 8761: 8758: 8755: 8750: 8746: 8742: 8739: 8689: 8630:(for integers 8620: 8619: 8603: 8600: 8597: 8594: 8591: 8586: 8582: 8578: 8575: 8570: 8566: 8562: 8557: 8553: 8549: 8544: 8540: 8534: 8530: 8503: 8494: 8485: 8476: 8459: 8443: 8440: 8437: 8434: 8431: 8426: 8422: 8414: 8410: 8406: 8401: 8398: 8395: 8392: 8389: 8386: 8383: 8378: 8374: 8321: 8310: 8307: 8304: 8301: 8298: 8295: 8290: 8287: 8284: 8280: 8274: 8271: 8266: 8263: 8260: 8257: 8254: 8249: 8245: 8237: 8233: 8229: 8224: 8221: 8218: 8213: 8209: 8201: 8197: 8193: 8188: 8185: 8182: 8177: 8173: 8169: 8166: 8111: 8099: 8096: 8093: 8090: 8087: 8084: 8081: 8078: 8075: 8072: 8069: 8066: 8063: 8043: 8040: 8037: 8034: 8031: 8028: 8025: 8022: 8019: 8016: 8013: 8010: 8007: 7981: 7967: 7947: 7930: 7921: 7887:(for integers 7882: 7859:) = 0 for all 7797: 7794: 7793: 7792: 7781: 7778: 7775: 7770: 7766: 7762: 7759: 7756: 7753: 7748: 7744: 7740: 7737: 7734: 7731: 7726: 7722: 7718: 7715: 7712: 7709: 7706: 7701: 7697: 7693: 7690: 7685: 7681: 7657: 7646: 7645: 7634: 7631: 7628: 7625: 7622: 7617: 7614: 7611: 7607: 7603: 7600: 7597: 7594: 7589: 7585: 7581: 7578: 7575: 7572: 7569: 7564: 7560: 7556: 7553: 7548: 7544: 7540: 7537: 7534: 7531: 7526: 7522: 7518: 7515: 7512: 7509: 7504: 7500: 7496: 7493: 7479: 7478: 7463: 7460: 7458: 7455: 7453: 7450: 7449: 7446: 7443: 7440: 7437: 7436: 7433: 7430: 7427: 7422: 7418: 7414: 7411: 7409: 7406: 7404: 7401: 7400: 7377: 7374: 7371: 7351: 7348: 7321: 7316: 7311: 7306: 7303: 7283: 7263: 7259: 7255: 7252: 7241: 7240: 7228: 7222: 7216: 7212: 7208: 7205: 7202: 7197: 7193: 7188: 7182: 7176: 7172: 7168: 7165: 7162: 7157: 7153: 7148: 7143: 7136: 7127: 7124: 7110: 7109: 7096: 7091: 7082: 7077: 7071: 7067: 7064: 7059: 7055: 7051: 7047: 7042: 7038: 7035: 7032: 7027: 7022: 7019: 7015: 7011: 7006: 7003: 6998: 6995: 6990: 6985: 6980: 6977: 6974: 6969: 6965: 6941: 6938: 6935: 6915: 6895: 6884:étale topology 6871: 6846: 6841: 6815: 6802: 6799: 6784: 6771: 6731: 6717: 6700: 6682: 6665:of sheaves on 6606:of sheaves on 6542:constant sheaf 6503:Main article: 6500: 6497: 6451:developed the 6400:Lev Pontryagin 6359: 6358: 6347: 6344: 6341: 6338: 6333: 6330: 6327: 6324: 6321: 6317: 6313: 6310: 6307: 6304: 6299: 6295: 6291: 6288: 6285: 6282: 6277: 6273: 6211:Henri Poincaré 6202: 6199: 6182: 6179: 6176: 6173: 6170: 6165: 6162: 6159: 6155: 6149: 6146: 6141: 6138: 6135: 6132: 6129: 6124: 6120: 6097: 6045: 6028: 5975: 5974: 5963: 5960: 5957: 5954: 5951: 5948: 5945: 5942: 5939: 5934: 5930: 5926: 5923: 5918: 5914: 5910: 5907: 5904: 5901: 5898: 5895: 5890: 5886: 5852: 5851: 5840: 5837: 5834: 5831: 5828: 5823: 5819: 5815: 5812: 5809: 5806: 5803: 5800: 5795: 5791: 5787: 5784: 5781: 5778: 5775: 5772: 5767: 5763: 5736: 5735: 5724: 5721: 5718: 5715: 5712: 5707: 5704: 5701: 5697: 5693: 5690: 5687: 5684: 5681: 5678: 5673: 5669: 5665: 5662: 5659: 5656: 5653: 5650: 5645: 5641: 5637: 5634: 5608:Main article: 5605: 5602: 5585: 5582: 5578: 5573: 5569: 5566: 5563: 5558: 5554: 5550: 5547: 5523: 5520: 5516: 5511: 5507: 5504: 5501: 5496: 5492: 5463: 5460: 5457: 5452: 5448: 5427: 5424: 5421: 5418: 5415: 5412: 5407: 5403: 5399: 5396: 5393: 5373: 5370: 5367: 5364: 5361: 5356: 5352: 5326:, also called 5303: 5300: 5297: 5294: 5291: 5286: 5282: 5248: 5244: 5240: 5237: 5215: 5211: 5201:of a point on 5186: 5182: 5178: 5175: 5172: 5167: 5163: 5140: 5136: 5115: 5112: 5109: 5105: 5101: 5098: 5067: 5064: 5061: 5058: 5055: 5040: 5039: 5028: 5025: 5022: 5019: 5016: 5011: 5007: 4999: 4994: 4987: 4984: 4981: 4978: 4975: 4972: 4969: 4966: 4963: 4960: 4933: 4930: 4927: 4924: 4921: 4918: 4915: 4912: 4880: 4877: 4874: 4871: 4868: 4865: 4862: 4859: 4856: 4853: 4848: 4844: 4803: 4800: 4797: 4794: 4791: 4788: 4765:Main article: 4762: 4759: 4663:Main article: 4660: 4657: 4597: 4596: 4585: 4582: 4579: 4576: 4573: 4570: 4567: 4562: 4558: 4554: 4551: 4548: 4545: 4542: 4539: 4534: 4531: 4528: 4524: 4520: 4517: 4514: 4511: 4508: 4505: 4500: 4496: 4445:Main article: 4442: 4439: 4427: 4424: 4421: 4418: 4415: 4412: 4409: 4406: 4401: 4398: 4395: 4391: 4387: 4384: 4381: 4378: 4375: 4370: 4366: 4362: 4359: 4356: 4353: 4350: 4345: 4341: 4337: 4334: 4331: 4328: 4325: 4231: 4228: 4225: 4222: 4219: 4216: 4211: 4208: 4205: 4201: 4197: 4194: 4191: 4188: 4185: 4182: 4177: 4173: 4169: 4166: 4163: 4019: 4016: 4015: 4014: 4013:coefficients). 3955: 3944: 3936: 3918: 3910: 3893: 3885: 3868: 3860: 3851: 3843: 3830: 3823: 3814: 3807: 3786: 3740: 3639: 3628: 3625: 3622: 3619: 3616: 3613: 3608: 3604: 3598: 3594: 3590: 3587: 3584: 3581: 3578: 3573: 3569: 3565: 3562: 3559: 3556: 3553: 3550: 3547: 3544: 3539: 3535: 3519:tensor product 3468: 3451: := and 3422: 3418: 3412: 3408: 3404: 3370: 3366: 3327: 3323: 3317: 3313: 3309: 3295: 3249: 3245: 3218: 3194: 3191: 3162: 3159: 3156: 3153: 3150: 3145: 3141: 3120: 3117: 3114: 3111: 3106: 3103: 3099: 3095: 3092: 3072: 3069: 3066: 3063: 3060: 3055: 3051: 3026: 3023: 3020: 3015: 3012: 3008: 2987: 2984: 2981: 2976: 2972: 2968: 2965: 2962: 2959: 2956: 2953: 2948: 2944: 2918:to a manifold 2899: 2896: 2893: 2888: 2884: 2851: 2848: 2845: 2840: 2836: 2826:, elements of 2820: 2819: 2795: 2791: 2786: 2764: 2752:chain homotopy 2724: 2635: 2632: 2629: 2626: 2621: 2618: 2615: 2611: 2607: 2604: 2601: 2598: 2595: 2592: 2589: 2586: 2583: 2580: 2577: 2574: 2571: 2508: 2457:of a manifold 2420: 2417: 2414: 2411: 2408: 2403: 2399: 2395: 2392: 2389: 2386: 2383: 2380: 2375: 2371: 2367: 2362: 2358: 2334: 2331: 2328: 2325: 2322: 2319: 2297: 2294: 2291: 2288: 2285: 2282: 2277: 2273: 2269: 2266: 2263: 2260: 2257: 2254: 2251: 2248: 2243: 2239: 2235: 2232: 2228: 2225: 2222: 2217: 2214: 2210: 2206: 2203: 2200: 2197: 2194: 2191: 2153: 2150: 2147: 2144: 2141: 2136: 2132: 2126: 2122: 2118: 2115: 2112: 2109: 2106: 2103: 2098: 2094: 2069:is written as 2050: 2047: 2044: 2041: 2038: 2035: 2030: 2027: 2024: 2020: 2016: 2013: 2010: 2007: 2004: 2001: 1996: 1992: 1988: 1985: 1982: 1979: 1976: 1973: 1968: 1964: 1934: 1933: 1869: 1866: 1863: 1860: 1857: 1852: 1848: 1824: 1812: 1809: 1806: 1803: 1800: 1795: 1791: 1763: 1760: 1757: 1754: 1751: 1746: 1742: 1714: 1711: 1708: 1705: 1702: 1699: 1695: 1691: 1688: 1685: 1680: 1676: 1672: 1669: 1663: 1658: 1654: 1651: 1648: 1645: 1642: 1639: 1634: 1630: 1626: 1623: 1620: 1617: 1614: 1610: 1606: 1603: 1600: 1597: 1592: 1589: 1586: 1582: 1578: 1575: 1570: 1564: 1559: 1555: 1552: 1530: 1519: 1516: 1513: 1510: 1507: 1504: 1501: 1496: 1493: 1490: 1486: 1482: 1479: 1476: 1473: 1468: 1464: 1460: 1457: 1454: 1451: 1446: 1442: 1438: 1435: 1432: 1429: 1426: 1423: 1418: 1414: 1410: 1407: 1376: 1373: 1370: 1367: 1364: 1361: 1358: 1353: 1349: 1333: 1322: 1319: 1316: 1313: 1310: 1305: 1302: 1299: 1295: 1291: 1288: 1285: 1282: 1279: 1276: 1271: 1267: 1263: 1260: 1257: 1254: 1249: 1245: 1241: 1238: 1235: 1232: 1227: 1223: 1219: 1216: 1213: 1210: 1205: 1201: 1197: 1194: 1160: 1145: 1125: 1122: 1119: 1114: 1110: 1106: 1103: 1100: 1097: 1092: 1088: 1084: 1079: 1075: 1050: 1047: 1044: 1039: 1035: 1031: 1028: 1025: 1022: 1017: 1013: 1009: 1004: 1000: 975: 972: 969: 966: 963: 913:of cocycles). 861:-simplices in 824: 819: 815: 801:) is zero for 771: 763: 728: 725: 720: 715: 712: 709: 705: 695: 692: 689: 685: 679: 670: 665: 661: 648: 644: 638: 629: 624: 621: 618: 614: 610: 607: 582: 577: 572: 568: 564: 559: 554: 551: 548: 544: 540: 535: 532: 529: 525: 499: 495: 474: 471: 468: 465: 460: 456: 452: 448: 445: 442: 438: 433: 428: 424: 407: 388: 375: 370:-simplices in 350: 328: 325: 320: 317: 314: 310: 297: 293: 287: 278: 274: 264: 261: 258: 254: 248: 239: 236: 233: 229: 225: 222: 165:continuous map 153: 150: 48:abelian groups 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 10861: 10850: 10847: 10846: 10844: 10829: 10821: 10817: 10814: 10812: 10809: 10807: 10804: 10803: 10802: 10794: 10792: 10788: 10784: 10782: 10778: 10774: 10772: 10767: 10762: 10760: 10752: 10751: 10748: 10742: 10739: 10737: 10734: 10732: 10729: 10727: 10724: 10722: 10719: 10717: 10714: 10713: 10711: 10709: 10705: 10699: 10698:Orientability 10696: 10694: 10691: 10689: 10686: 10684: 10681: 10679: 10676: 10675: 10673: 10669: 10663: 10660: 10658: 10655: 10653: 10650: 10648: 10645: 10643: 10640: 10638: 10635: 10633: 10630: 10626: 10623: 10621: 10618: 10617: 10616: 10613: 10609: 10606: 10604: 10601: 10599: 10596: 10594: 10591: 10589: 10586: 10585: 10584: 10581: 10579: 10576: 10574: 10571: 10569: 10565: 10562: 10561: 10559: 10555: 10550: 10540: 10537: 10535: 10534:Set-theoretic 10532: 10528: 10525: 10524: 10523: 10520: 10516: 10513: 10512: 10511: 10508: 10506: 10503: 10501: 10498: 10496: 10495:Combinatorial 10493: 10491: 10488: 10486: 10483: 10482: 10480: 10476: 10472: 10465: 10460: 10458: 10453: 10451: 10446: 10445: 10442: 10435: 10431: 10427: 10423: 10419: 10415: 10411: 10407: 10406: 10401: 10397: 10393: 10390: 10386: 10382: 10380:3-540-42750-3 10376: 10372: 10368: 10363: 10360: 10356: 10352: 10350:0-226-51182-0 10346: 10342: 10335: 10334: 10329: 10328:May, J. Peter 10325: 10320: 10316: 10315: 10310: 10306: 10303: 10299: 10295: 10293:0-521-79540-0 10289: 10285: 10281: 10280: 10275: 10271: 10268: 10264: 10260: 10258:0-387-90244-9 10254: 10250: 10246: 10242: 10238: 10235: 10231: 10227: 10225:9780691627236 10221: 10217: 10213: 10209: 10205: 10201: 10198: 10194: 10190: 10184: 10180: 10176: 10172: 10168: 10165: 10161: 10157: 10155:0-8176-3388-X 10151: 10147: 10142: 10141: 10135: 10131: 10130: 10126: 10119: 10114: 10111: 10106: 10102: 10096: 10093: 10089: 10084: 10081: 10078:, p. 95. 10077: 10072: 10069: 10065: 10060: 10057: 10053: 10048: 10045: 10041: 10036: 10033: 10029: 10024: 10021: 10017: 10012: 10009: 10005: 10000: 9997: 9993: 9988: 9985: 9981: 9976: 9974: 9970: 9966: 9961: 9958: 9954: 9949: 9946: 9942: 9937: 9934: 9930: 9925: 9922: 9918: 9913: 9910: 9906: 9901: 9898: 9894: 9890: 9885: 9882: 9878: 9873: 9870: 9864: 9860: 9857: 9856: 9852: 9847: 9844: 9842: 9839: 9837: 9834: 9832: 9829: 9827: 9824: 9822: 9819: 9817: 9814: 9812: 9809: 9807: 9804: 9802: 9799: 9797: 9794: 9792: 9789: 9787: 9784: 9782: 9779: 9777: 9774: 9772: 9769: 9767: 9764: 9762: 9759: 9757: 9754: 9752: 9749: 9747: 9744: 9742: 9739: 9737: 9734: 9732: 9729: 9728: 9726: 9720: 9718: 9716: 9715:ring spectrum 9711: 9707:, such as an 9706: 9705:ring spectrum 9702: 9683: 9675: 9671: 9662: 9658: 9653: 9647: 9643: 9640: 9636: 9633: 9615: 9607: 9603: 9599: 9576: 9568: 9564: 9540: 9532: 9528: 9524: 9501: 9493: 9489: 9485: 9477: 9473: 9470: 9466: 9465:formal groups 9450: 9444: 9436: 9432: 9428: 9421: 9406: 9400: 9392: 9388: 9384: 9381: 9358: 9350: 9346: 9342: 9334: 9330: 9316: 9310: 9302: 9297: 9293: 9285: 9269: 9263: 9255: 9250: 9246: 9238: 9234: 9233: 9232: 9229: 9226: 9221: 9219: 9215: 9209: 9206: 9202: 9194: 9173: 9169: 9165: 9160: 9156: 9147: 9143: 9137: 9133: 9123: 9120: 9117: 9109: 9105: 9096: 9095:product group 9092: 9088: 9083: 9079: 9074: 9070: 9065: 9061: 9056: 9052: 9048: 9044: 9040: 9037: 9034: 9015: 9012: 9009: 9006: 9003: 8995: 8991: 8983: 8979: 8967: 8964: 8961: 8953: 8949: 8940: 8936: 8932: 8928: 8924: 8920: 8916: 8912: 8908: 8904: 8901: 8887: 8884: 8875: 8872: 8869: 8861: 8858: 8855: 8851: 8845: 8834: 8826: 8822: 8814: 8810: 8798: 8790: 8786: 8778: 8774: 8762: 8759: 8756: 8748: 8744: 8737: 8729: 8725: 8721: 8717: 8713: 8709: 8705: 8701: 8697: 8694:: Each pair ( 8693: 8690: 8687: 8684: 8683: 8682: 8680: 8676: 8672: 8668: 8664: 8658: 8654: 8650: 8646: 8642: 8638: 8633: 8629: 8625: 8617: 8598: 8595: 8592: 8584: 8580: 8568: 8564: 8560: 8555: 8551: 8542: 8538: 8532: 8528: 8519: 8515: 8511: 8506: 8502: 8497: 8493: 8488: 8484: 8479: 8475: 8471: 8467: 8463: 8460: 8457: 8438: 8435: 8432: 8424: 8420: 8412: 8408: 8396: 8393: 8390: 8387: 8384: 8376: 8372: 8363: 8359: 8355: 8351: 8347: 8343: 8339: 8335: 8331: 8327: 8326: 8322: 8308: 8305: 8296: 8288: 8285: 8282: 8278: 8261: 8258: 8255: 8247: 8243: 8235: 8231: 8219: 8211: 8207: 8199: 8195: 8183: 8175: 8171: 8164: 8154: 8150: 8146: 8142: 8136: 8132: 8128: 8123: 8119: 8116:: Each pair ( 8115: 8112: 8094: 8091: 8088: 8076: 8073: 8070: 8064: 8061: 8038: 8035: 8032: 8020: 8017: 8014: 8008: 8005: 7997: 7994: 7993: 7992: 7990: 7984: 7980: 7976: 7970: 7966: 7962: 7956: 7950: 7946: 7942: 7938: 7933: 7929: 7924: 7918: 7914: 7910: 7906: 7902: 7898: 7894: 7890: 7885: 7881: 7878: 7874: 7869: 7866: 7862: 7858: 7854: 7850: 7846: 7841: 7839: 7835: 7831: 7827: 7823: 7819: 7815: 7811: 7805: 7800: 7795: 7776: 7768: 7764: 7760: 7754: 7746: 7742: 7738: 7732: 7724: 7720: 7716: 7707: 7699: 7695: 7691: 7683: 7679: 7671: 7670: 7669: 7655: 7632: 7623: 7615: 7612: 7609: 7605: 7595: 7587: 7583: 7570: 7562: 7558: 7554: 7546: 7542: 7538: 7532: 7524: 7520: 7510: 7502: 7498: 7491: 7484: 7483: 7482: 7461: 7451: 7428: 7420: 7416: 7412: 7402: 7391: 7390: 7389: 7375: 7372: 7369: 7349: 7346: 7337: 7335: 7314: 7301: 7281: 7250: 7226: 7220: 7214: 7210: 7206: 7203: 7200: 7195: 7191: 7186: 7180: 7174: 7170: 7166: 7163: 7160: 7155: 7151: 7146: 7134: 7125: 7122: 7115: 7114: 7113: 7094: 7080: 7069: 7057: 7053: 7045: 7036: 7033: 7025: 7020: 7017: 7013: 7009: 7004: 7001: 6996: 6988: 6978: 6975: 6967: 6963: 6955: 6954: 6953: 6939: 6936: 6933: 6913: 6893: 6885: 6869: 6860: 6844: 6829: 6813: 6800: 6798: 6796: 6792: 6787: 6783: 6779: 6774: 6770: 6766: 6762: 6758: 6754: 6750: 6745: 6743: 6739: 6734: 6729: 6725: 6720: 6715: 6711: 6707: 6703: 6698: 6694: 6690: 6685: 6680: 6676: 6670: 6668: 6664: 6660: 6656: 6651: 6649: 6645: 6641: 6637: 6633: 6629: 6625: 6621: 6617: 6613: 6609: 6605: 6601: 6597: 6593: 6589: 6587: 6583: 6579: 6575: 6571: 6567: 6563: 6559: 6555: 6551: 6547: 6543: 6539: 6535: 6531: 6527: 6523: 6519: 6515: 6511: 6506: 6498: 6496: 6494: 6490: 6489:Edwin Spanier 6485: 6483: 6478: 6476: 6472: 6467: 6465: 6460: 6458: 6454: 6450: 6446: 6441: 6439: 6435: 6430: 6428: 6424: 6419: 6417: 6413: 6409: 6405: 6401: 6396: 6394: 6390: 6385: 6383: 6379: 6375: 6370: 6368: 6364: 6345: 6339: 6331: 6328: 6325: 6322: 6319: 6315: 6305: 6297: 6293: 6289: 6283: 6275: 6271: 6263: 6262: 6261: 6259: 6255: 6252: +  6251: 6247: 6243: 6240:-cycle and a 6239: 6235: 6231: 6227: 6223: 6219: 6214: 6212: 6208: 6200: 6198: 6196: 6177: 6174: 6171: 6163: 6160: 6157: 6153: 6147: 6136: 6133: 6130: 6122: 6118: 6109: 6105: 6100: 6096: 6092: 6088: 6085:of dimension 6084: 6079: 6077: 6073: 6069: 6065: 6061: 6057: 6052: 6048: 6044: 6040: 6036: 6031: 6027: 6023: 6019: 6015: 6011: 6007: 6003: 5999: 5995: 5991: 5987: 5982: 5980: 5961: 5955: 5952: 5946: 5943: 5940: 5932: 5928: 5921: 5916: 5912: 5902: 5899: 5896: 5888: 5884: 5876: 5875: 5874: 5872: 5868: 5863: 5861: 5857: 5835: 5832: 5829: 5821: 5817: 5807: 5804: 5801: 5793: 5789: 5785: 5779: 5776: 5773: 5765: 5761: 5753: 5752: 5751: 5749: 5745: 5741: 5719: 5716: 5713: 5705: 5702: 5699: 5695: 5685: 5682: 5679: 5671: 5667: 5663: 5657: 5654: 5651: 5643: 5639: 5635: 5632: 5625: 5624: 5623: 5621: 5617: 5611: 5603: 5601: 5599: 5580: 5576: 5567: 5564: 5556: 5552: 5548: 5545: 5537: 5518: 5514: 5505: 5502: 5494: 5490: 5481: 5477: 5458: 5450: 5446: 5422: 5419: 5413: 5405: 5401: 5394: 5391: 5368: 5365: 5362: 5354: 5350: 5341: 5337: 5333: 5331: 5325: 5321: 5317: 5298: 5295: 5292: 5284: 5280: 5271: 5267: 5262: 5246: 5242: 5235: 5213: 5209: 5200: 5176: 5173: 5165: 5161: 5138: 5134: 5110: 5107: 5096: 5087: 5085: 5081: 5062: 5059: 5056: 5045: 5023: 5020: 5017: 5009: 5005: 4997: 4979: 4976: 4973: 4967: 4964: 4961: 4951: 4950: 4949: 4947: 4928: 4925: 4922: 4916: 4910: 4902: 4898: 4894: 4875: 4872: 4866: 4863: 4860: 4854: 4846: 4842: 4833: 4829: 4825: 4821: 4817: 4798: 4795: 4792: 4786: 4778: 4774: 4768: 4760: 4758: 4756: 4752: 4748: 4747:Chern classes 4744: 4739: 4737: 4733: 4729: 4725: 4721: 4717: 4713: 4709: 4705: 4701: 4697: 4693: 4692: 4687: 4683: 4679: 4675: 4672: 4671:vector bundle 4666: 4658: 4656: 4654: 4650: 4646: 4642: 4638: 4634: 4630: 4626: 4622: 4618: 4614: 4610: 4606: 4602: 4583: 4580: 4574: 4571: 4568: 4560: 4556: 4546: 4543: 4540: 4532: 4529: 4526: 4522: 4518: 4512: 4509: 4506: 4498: 4494: 4486: 4485: 4484: 4482: 4478: 4474: 4470: 4466: 4462: 4458: 4454: 4448: 4440: 4438: 4425: 4419: 4416: 4413: 4410: 4407: 4399: 4396: 4393: 4389: 4385: 4376: 4368: 4364: 4351: 4343: 4339: 4332: 4329: 4326: 4323: 4315: 4311: 4307: 4303: 4299: 4295: 4291: 4287: 4283: 4279: 4275: 4271: 4267: 4263: 4259: 4255: 4251: 4247: 4242: 4229: 4223: 4220: 4217: 4209: 4206: 4203: 4199: 4195: 4189: 4186: 4183: 4175: 4167: 4164: 4161: 4153: 4149: 4145: 4141: 4137: 4133: 4129: 4125: 4121: 4117: 4113: 4109: 4105: 4101: 4097: 4096:cross product 4093: 4089: 4085: 4081: 4077: 4073: 4069: 4065: 4061: 4057: 4053: 4049: 4045: 4041: 4037: 4033: 4029: 4025: 4017: 4012: 4008: 4004: 4000: 3996: 3992: 3988: 3984: 3980: 3976: 3972: 3968: 3964: 3960: 3956: 3952: 3947: 3943: 3939: 3935: 3930: 3926: 3921: 3917: 3913: 3909: 3905: 3901: 3896: 3892: 3888: 3884: 3880: 3876: 3871: 3867: 3863: 3859: 3854: 3850: 3846: 3842: 3838: 3833: 3829: 3822: 3817: 3813: 3806: 3802: 3798: 3795: 3791: 3787: 3784: 3780: 3776: 3772: 3768: 3764: 3760: 3756: 3752: 3748: 3745: 3741: 3738: 3734: 3730: 3726: 3722: 3718: 3714: 3710: 3706: 3702: 3698: 3694: 3690: 3686: 3682: 3678: 3674: 3671: 3667: 3663: 3659: 3655: 3651: 3647: 3644: 3640: 3626: 3620: 3617: 3614: 3606: 3602: 3596: 3592: 3585: 3582: 3579: 3571: 3567: 3563: 3557: 3554: 3551: 3548: 3545: 3537: 3533: 3524: 3520: 3516: 3512: 3509: 3508:product space 3505: 3501: 3497: 3493: 3489: 3485: 3481: 3477: 3473: 3469: 3466: 3462: 3458: 3454: 3450: 3446: 3444: 3438: 3420: 3410: 3406: 3394: 3390: 3386: 3368: 3364: 3355: 3351: 3347: 3343: 3325: 3315: 3311: 3300: 3296: 3293: 3289: 3285: 3281: 3278:by the given 3277: 3273: 3272:quotient ring 3269: 3265: 3247: 3243: 3235: 3231: 3223: 3219: 3216: 3212: 3208: 3204: 3203: 3202: 3200: 3192: 3190: 3188: 3184: 3180: 3176: 3154: 3143: 3139: 3118: 3112: 3104: 3101: 3097: 3093: 3090: 3064: 3053: 3049: 3040: 3021: 3013: 3010: 3006: 2982: 2974: 2970: 2966: 2957: 2946: 2942: 2933: 2929: 2925: 2921: 2917: 2913: 2894: 2886: 2882: 2873: 2869: 2866:subspaces of 2865: 2846: 2838: 2834: 2825: 2817: 2813: 2809: 2793: 2789: 2753: 2749: 2745: 2741: 2737: 2733: 2729: 2725: 2721: 2717: 2713: 2709: 2705: 2704:normal bundle 2701: 2697: 2693: 2689: 2685: 2681: 2677: 2673: 2669: 2665: 2661: 2657: 2653: 2649: 2633: 2627: 2619: 2616: 2613: 2609: 2605: 2599: 2596: 2593: 2587: 2581: 2572: 2561: 2557: 2553: 2549: 2545: 2541: 2538: 2534: 2530: 2527: 2523: 2519: 2515: 2511: 2507: 2503: 2500: 2496: 2492: 2488: 2484: 2480: 2479: 2478: 2476: 2472: 2468: 2464: 2463:closed subset 2460: 2456: 2453: 2449: 2444: 2442: 2438: 2434: 2415: 2412: 2409: 2401: 2397: 2387: 2384: 2381: 2373: 2369: 2365: 2360: 2356: 2348: 2332: 2329: 2323: 2320: 2317: 2308: 2295: 2289: 2286: 2283: 2275: 2271: 2267: 2264: 2261: 2255: 2252: 2249: 2241: 2237: 2233: 2230: 2226: 2223: 2220: 2215: 2212: 2204: 2201: 2195: 2192: 2189: 2181: 2177: 2173: 2172: 2168:, called the 2167: 2148: 2145: 2142: 2134: 2130: 2124: 2120: 2116: 2110: 2107: 2104: 2096: 2092: 2084: 2080: 2077:or simply as 2076: 2072: 2068: 2064: 2048: 2042: 2039: 2036: 2028: 2025: 2022: 2018: 2008: 2005: 2002: 1994: 1990: 1986: 1980: 1977: 1974: 1966: 1962: 1953: 1952: 1948:, called the 1947: 1944:, there is a 1943: 1939: 1931: 1927: 1923: 1919: 1915: 1911: 1907: 1903: 1899: 1895: 1891: 1887: 1883: 1880:are zero for 1864: 1861: 1858: 1850: 1846: 1837: 1833: 1829: 1825: 1807: 1804: 1801: 1793: 1789: 1781: 1777: 1758: 1755: 1752: 1744: 1740: 1731: 1728: 1712: 1703: 1700: 1689: 1686: 1678: 1674: 1667: 1656: 1646: 1643: 1640: 1632: 1628: 1618: 1615: 1604: 1601: 1595: 1590: 1587: 1584: 1573: 1568: 1557: 1550: 1543: 1539: 1535: 1531: 1517: 1508: 1505: 1502: 1494: 1491: 1488: 1484: 1474: 1466: 1462: 1452: 1444: 1440: 1430: 1427: 1424: 1416: 1412: 1405: 1397: 1393: 1390: 1371: 1368: 1365: 1362: 1359: 1351: 1347: 1338: 1334: 1320: 1311: 1303: 1300: 1297: 1293: 1283: 1280: 1277: 1269: 1265: 1255: 1247: 1243: 1239: 1233: 1225: 1221: 1211: 1203: 1199: 1192: 1184: 1180: 1176: 1173: 1169: 1165: 1161: 1158: 1154: 1150: 1146: 1143: 1139: 1120: 1112: 1108: 1098: 1090: 1086: 1082: 1077: 1073: 1065:homomorphism 1064: 1045: 1037: 1033: 1023: 1015: 1011: 1007: 1002: 998: 990:homomorphism 989: 986:determines a 973: 967: 964: 961: 953: 952: 951: 948: 946: 942: 938: 934: 930: 927: 923: 919: 914: 912: 908: 905:) are called 904: 900: 896: 892: 888: 884: 880: 877:) are called 876: 872: 868: 864: 860: 856: 852: 848: 844: 842: 822: 817: 813: 804: 800: 796: 792: 789:). The group 788: 784: 780: 774: 770: 766: 759: 755: 751: 748: 744: 739: 726: 718: 713: 710: 707: 703: 693: 690: 687: 683: 668: 663: 659: 646: 642: 627: 622: 619: 616: 612: 605: 598: 593: 580: 575: 570: 566: 557: 552: 549: 546: 542: 538: 533: 530: 527: 523: 515: 497: 472: 466: 463: 458: 454: 436: 431: 426: 422: 414: 410: 403: 398: 396: 393:are zero for 391: 387: 383: 378: 373: 369: 365: 361: 357: 353: 346: 342: 326: 318: 315: 312: 308: 295: 276: 272: 262: 259: 256: 237: 234: 231: 227: 220: 212: 208: 203: 201: 197: 193: 189: 185: 181: 178:determines a 177: 173: 169: 166: 162: 158: 151: 149: 147: 143: 139: 134: 130: 125: 120: 116: 112: 108: 104: 100: 96: 92: 88: 84: 83:contravariant 80: 76: 72: 67: 65: 61: 57: 53: 49: 45: 41: 37: 33: 19: 10828:Publications 10693:Chern number 10683:Betti number 10566: / 10557:Key concepts 10526: 10505:Differential 10409: 10403: 10366: 10332: 10312: 10309:"Cohomology" 10278: 10244: 10211: 10174: 10139: 10118:Switzer 1975 10113: 10105:MathOverflow 10104: 10095: 10088:Switzer 1975 10083: 10071: 10059: 10047: 10035: 10028:Hatcher 2001 10023: 10016:Hatcher 2001 10011: 10004:Hatcher 2001 9999: 9992:Hatcher 2001 9987: 9980:Hatcher 2001 9965:Hatcher 2001 9960: 9953:Hatcher 2001 9948: 9936: 9924: 9917:Hatcher 2001 9912: 9900: 9884: 9877:Hatcher 2001 9872: 9724: 9709: 9700: 9660: 9656: 9654: 9651: 9230: 9222: 9218:triangulated 9214:phantom maps 9210: 9198: 9192: 9090: 9086: 9081: 9077: 9072: 9068: 9063: 9059: 9054: 9050: 9046: 9042: 9038: 9032: 8938: 8934: 8930: 8926: 8922: 8918: 8914: 8910: 8906: 8902: 8727: 8723: 8719: 8715: 8711: 8707: 8703: 8699: 8695: 8691: 8685: 8678: 8674: 8670: 8666: 8662: 8656: 8652: 8648: 8644: 8640: 8636: 8631: 8627: 8623: 8621: 8615: 8513: 8509: 8504: 8500: 8495: 8491: 8486: 8482: 8477: 8473: 8469: 8465: 8461: 8455: 8361: 8357: 8353: 8349: 8345: 8341: 8337: 8333: 8329: 8323: 8152: 8148: 8144: 8140: 8134: 8130: 8126: 8121: 8117: 8113: 7995: 7988: 7982: 7978: 7974: 7968: 7964: 7960: 7954: 7948: 7944: 7940: 7936: 7931: 7927: 7922: 7912: 7908: 7904: 7900: 7888: 7883: 7879: 7872: 7870: 7860: 7856: 7852: 7848: 7844: 7842: 7807: 7799: 7647: 7480: 7338: 7242: 7111: 6861: 6804: 6794: 6790: 6785: 6781: 6777: 6772: 6768: 6764: 6760: 6756: 6752: 6748: 6746: 6741: 6737: 6732: 6727: 6723: 6718: 6709: 6705: 6701: 6696: 6692: 6688: 6683: 6674: 6671: 6666: 6654: 6652: 6647: 6643: 6639: 6627: 6623: 6619: 6615: 6611: 6607: 6599: 6592:Grothendieck 6590: 6569: 6565: 6561: 6557: 6553: 6549: 6545: 6537: 6533: 6529: 6525: 6521: 6517: 6509: 6508: 6486: 6479: 6474: 6468: 6461: 6442: 6436:constructed 6431: 6420: 6397: 6386: 6381: 6377: 6373: 6371: 6366: 6360: 6257: 6253: 6249: 6241: 6237: 6233: 6229: 6215: 6206: 6204: 6194: 6107: 6103: 6098: 6094: 6086: 6082: 6080: 6075: 6071: 6067: 6063: 6059: 6055: 6050: 6046: 6042: 6038: 6034: 6029: 6025: 6021: 6017: 6013: 6009: 6005: 6001: 5997: 5993: 5992:submanifold 5989: 5985: 5983: 5978: 5976: 5870: 5866: 5864: 5859: 5855: 5853: 5747: 5743: 5739: 5737: 5619: 5615: 5613: 5597: 5535: 5479: 5339: 5335: 5329: 5323: 5319: 5269: 5265: 5263: 5228:by some map 5198: 5088: 5083: 5079: 5043: 5041: 4945: 4900: 4896: 4892: 4831: 4827: 4823: 4819: 4815: 4776: 4772: 4770: 4740: 4735: 4731: 4727: 4723: 4719: 4715: 4707: 4703: 4699: 4695: 4689: 4685: 4681: 4677: 4673: 4668: 4652: 4648: 4644: 4640: 4636: 4628: 4624: 4620: 4616: 4612: 4608: 4604: 4598: 4480: 4476: 4472: 4468: 4464: 4460: 4455:be a closed 4452: 4450: 4313: 4309: 4305: 4301: 4297: 4293: 4289: 4285: 4281: 4277: 4273: 4269: 4265: 4261: 4257: 4253: 4249: 4245: 4243: 4151: 4147: 4143: 4139: 4135: 4131: 4127: 4123: 4119: 4115: 4111: 4107: 4103: 4099: 4095: 4091: 4087: 4083: 4079: 4075: 4071: 4067: 4063: 4059: 4055: 4051: 4047: 4043: 4039: 4035: 4031: 4027: 4024:diagonal map 4021: 4018:The diagonal 4010: 4006: 4002: 3998: 3994: 3990: 3986: 3982: 3978: 3974: 3970: 3966: 3962: 3958: 3950: 3945: 3941: 3937: 3933: 3928: 3924: 3919: 3915: 3911: 3907: 3903: 3899: 3894: 3890: 3886: 3882: 3878: 3874: 3873:= 0 for all 3869: 3865: 3861: 3857: 3852: 3848: 3844: 3840: 3836: 3831: 3827: 3820: 3815: 3811: 3804: 3800: 3796: 3789: 3782: 3778: 3774: 3770: 3766: 3762: 3758: 3754: 3750: 3746: 3736: 3732: 3728: 3724: 3720: 3716: 3712: 3708: 3704: 3700: 3696: 3692: 3688: 3684: 3680: 3676: 3672: 3665: 3661: 3657: 3653: 3649: 3645: 3522: 3514: 3510: 3502:.) Then the 3499: 3495: 3491: 3487: 3483: 3479: 3475: 3471: 3464: 3460: 3456: 3452: 3448: 3442: 3436: 3392: 3388: 3384: 3353: 3349: 3345: 3291: 3287: 3283: 3267: 3263: 3229: 3214: 3211:contractible 3206: 3198: 3196: 3186: 3182: 3178: 3174: 3038: 2931: 2927: 2926:submanifold 2923: 2919: 2915: 2911: 2871: 2867: 2863: 2823: 2821: 2815: 2807: 2743: 2735: 2727: 2715: 2711: 2707: 2699: 2695: 2691: 2687: 2683: 2679: 2671: 2667: 2663: 2659: 2655: 2651: 2647: 2560:transversely 2555: 2551: 2547: 2543: 2539: 2536: 2532: 2528: 2521: 2517: 2513: 2509: 2505: 2501: 2498: 2490: 2485:be a closed 2482: 2474: 2470: 2466: 2458: 2454: 2451: 2447: 2445: 2432: 2309: 2175: 2169: 2078: 2074: 2070: 2066: 2062: 1949: 1946:bilinear map 1941: 1937: 1935: 1929: 1921: 1917: 1913: 1909: 1901: 1893: 1889: 1881: 1827: 1780:vector space 1729: 1395: 1391: 1178: 1174: 1172:open subsets 1167: 1156: 1152: 1141: 1062: 987: 949: 940: 932: 928: 921: 917: 915: 906: 902: 898: 894: 890: 886: 883:coboundaries 882: 878: 874: 870: 866: 862: 858: 854: 853:-cochain on 850: 846: 840: 838: 802: 798: 794: 790: 786: 782: 778: 772: 768: 761: 757: 753: 749: 746: 742: 740: 594: 405: 401: 399: 394: 389: 385: 381: 376: 371: 367: 363: 362:-simplex to 359: 348: 344: 206: 204: 195: 191: 187: 183: 180:homomorphism 175: 171: 167: 156: 155: 137: 132: 128: 123: 118: 114: 110: 102: 98: 94: 90: 68: 43: 29: 10791:Wikiversity 10708:Key results 9893:Dold (1972) 8661:called the 7959:called the 7891:) from the 6457:cap product 6453:cup product 6449:Eduard Čech 6402:proved the 6363:cup product 5620:cap product 5610:Cap product 5604:Cap product 5322:with group 4691:Euler class 3735:in degree 2 3525:-algebras: 3387:the point ( 2818:cohomology. 2526:codimension 2166:graded ring 1951:cup product 1908:, then the 1394:of a space 988:pushforward 837:are called 186:to that of 142:cup product 32:mathematics 10637:CW complex 10578:Continuity 10568:Closed set 10527:cohomology 10396:Thom, René 10146:Birkhäuser 10127:References 9786:Ext groups 9191:for every 9039:Additivity 9031:for every 8614:for every 8518:direct sum 8462:Additivity 8454:for every 7802:See also: 7362:subscheme 6714:Ext groups 6679:Tor groups 6632:left exact 6482:Jean Leray 6416:characters 5328:principal 5272:. Namely, 4463:, and let 3670:hyperplane 3286:in degree 2083:direct sum 1836:CW complex 1776:dual space 1538:Ext groups 1335:There are 1151:maps from 1144:-modules). 413:dual group 397:negative. 105:, for any 44:cohomology 10816:geometric 10811:algebraic 10662:Cobordism 10598:Hausdorff 10593:connected 10510:Geometric 10500:Continuum 10490:Algebraic 10434:120243638 10412:: 17–86, 10319:EMS Press 9941:Thom 1954 9929:Thom 1954 9905:Dold 1972 9865:Citations 9676:∗ 9608:∗ 9569:∗ 9533:∗ 9494:∗ 9437:∗ 9393:∗ 9351:∗ 9333:cobordism 9298:∗ 9294:π 9256:∗ 9247:π 9174:α 9161:α 9138:α 9134:∏ 9130:→ 9013:∩ 8984:∗ 8976:→ 8885:⋯ 8882:→ 8843:→ 8815:∗ 8807:→ 8779:∗ 8771:→ 8741:→ 8738:⋯ 8692:Exactness 8665:(writing 8577:→ 8569:α 8556:α 8533:α 8529:⨁ 8413:∗ 8405:→ 8394:∩ 8306:⋯ 8303:→ 8286:− 8273:∂ 8270:→ 8236:∗ 8228:→ 8200:∗ 8192:→ 8168:→ 8165:⋯ 8114:Exactness 8083:→ 8027:→ 7761:⊕ 7739:≅ 7717:⊕ 7633:⋯ 7630:→ 7602:→ 7580:→ 7539:⊕ 7517:→ 7495:→ 7492:⋯ 7457:⟶ 7445:↓ 7439:↓ 7408:⟶ 7373:⊂ 7347:≥ 7282:ℓ 7204:… 7164:… 7095:ℓ 7081:ℓ 7070:⊗ 7054:ℓ 7010:⁡ 7005:← 6989:ℓ 6937:≠ 6934:ℓ 6914:ℓ 6780:), where 6480:In 1946, 6462:In 1944, 6432:In 1936, 6398:In 1934, 6387:In 1931, 6329:− 6312:→ 6290:× 6161:− 6148:≅ 6145:→ 5981:a field. 5922:⁡ 5909:→ 5822:∗ 5814:→ 5794:∗ 5786:× 5766:∗ 5703:− 5692:→ 5664:× 5633:∩ 5549:∈ 5447:π 5402:π 5395:⁡ 5239:→ 4998:≅ 4993:→ 4914:→ 4581:≅ 4553:→ 4530:− 4519:× 4457:connected 4411:× 4386:∈ 4369:∗ 4344:∗ 4327:× 4196:∈ 4187:× 4176:∗ 4172:Δ 3607:∗ 3593:⊗ 3572:∗ 3564:≅ 3549:× 3538:∗ 3144:∗ 3102:− 3094:− 3054:∗ 3011:− 2967:∈ 2947:∗ 2606:∈ 2597:∩ 2402:∗ 2394:→ 2374:∗ 2361:∗ 2327:→ 2321:: 2268:∈ 2234:∈ 2202:− 2121:⨁ 2097:∗ 2015:→ 1987:× 1928:for each 1886:dimension 1710:→ 1668:⁡ 1653:→ 1625:→ 1596:⁡ 1588:− 1574:⁡ 1554:→ 1518:⋯ 1515:→ 1481:→ 1459:→ 1437:→ 1409:→ 1406:⋯ 1321:⋯ 1318:→ 1290:→ 1281:∩ 1262:→ 1240:⊕ 1218:→ 1196:→ 1193:⋯ 1149:homotopic 1105:→ 1078:∗ 1030:→ 1003:∗ 971:→ 873:) and im( 843:-cochains 839:singular 823:∗ 727:⋯ 724:← 719:∗ 711:− 691:− 678:← 669:∗ 637:← 628:∗ 609:← 606:⋯ 576:∗ 563:→ 558:∗ 550:− 531:− 494:∂ 432:∗ 374:"), and ∂ 327:⋯ 324:→ 316:− 292:∂ 286:→ 253:∂ 247:→ 224:→ 221:⋯ 87:pullbacks 60:functions 10843:Category 10781:Wikibook 10759:Category 10647:Manifold 10615:Homotopy 10573:Interior 10564:Open set 10522:Homology 10471:Topology 10398:(1954), 10330:(1999), 10276:(2001), 10243:(1977), 10210:(1952), 10173:(1972), 10136:(1989), 10076:May 1999 10040:May 1999 9853:See also 9476:K-theory 9201:spectrum 8903:Excision 8686:Homotopy 8325:Excision 7996:Homotopy 7893:category 7877:functors 7274:and the 6487:In 1948 6224:founded 6209:, which 5438:, where 5332:-bundles 4676:of rank 4252:, write 3927:for all 3757:), with 3660:), with 3282:), with 3193:Examples 2487:oriented 2437:algebras 2347:pullback 2178:. It is 1912:-module 1832:manifold 1389:subspace 1387:for any 1063:pullback 945:integers 924:to be a 879:cocycles 113: : 75:geometry 71:topology 10806:general 10608:uniform 10588:compact 10539:Digital 10426:0061823 10389:0385836 10359:1702278 10321:, 2001 10302:1867354 10267:0463157 10234:0050886 10197:0415602 10164:0995842 10120:, 7.68. 9235:Stable 8722:,∅) → ( 8147:,∅) → ( 7903:,  5474:is the 4712:section 4633:torsion 3898:= 0 if 3719:=1,..., 3445:-module 3340:is the 3270:) (the 3185:inside 2814:on mod 2562:, then 2493:. Then 2164:into a 1898:compact 1778:of the 1339:groups 937:modules 512:by its 411:by its 380:is the 354:is the 107:mapping 79:algebra 10801:Topics 10603:metric 10478:Fields 10432:  10424:  10387:  10377:  10357:  10347:  10300:  10290:  10265:  10255:  10232:  10222:  10195:  10185:  10162:  10152:  9041:: If ( 8673:) for 8464:: If ( 7963:(here 7907:) (so 7895:of CW- 6677:, the 6471:axioms 6423:Moscow 6089:has a 5618:, the 5338:. For 4814:whose 4753:, and 4688:, the 4619:) and 4316:) is: 4300:) and 4138:) and 4074:) and 4009:(with 3997:(with 3989:/2 or 3906:, and 3723:. The 3383:, and 3234:sphere 2776:or in 2670:, and 745:, the 656:  305:  64:chains 10583:Space 10430:S2CID 10337:(PDF) 9205:Adams 9085:) → ( 8933:) → ( 8905:: If 8508:) → ( 8356:) → ( 8328:: If 7998:: If 7897:pairs 7847:: if 6514:sheaf 5334:over 4599:is a 3826:,..., 3810:,..., 3794:genus 3648:with 3517:is a 3441:free 3344:over 3299:torus 3280:ideal 3274:of a 2914:from 2738:with 2710:. If 2678:, if 2477:is). 1924:) is 1896:is a 1892:. If 1834:or a 1727:field 889:)/im( 767:)/im( 10375:ISBN 10345:ISBN 10288:ISBN 10253:ISBN 10220:ISBN 10183:ISBN 10150:ISBN 8913:and 8714:and 8647:) → 8336:and 8138:and 7943:) → 7828:for 7130:Proj 6576:and 6447:and 6220:and 6066:and 5865:For 5742:and 4698:) ∈ 4647:) ≅ 4268:and 4248:and 4094:(or 4054:and 3877:and 3819:and 3715:for 3656:/2/( 3478:and 2740:real 2720:Thom 2682:and 2554:and 2546:and 2481:Let 2345:the 2065:and 1532:The 1177:and 1162:The 1147:Two 893:) = 881:and 485:and 146:ring 93:and 77:and 38:and 10414:doi 9663:if 8921:: ( 8730:): 8718:: ( 8344:: ( 8143:: ( 7816:or 7002:lim 6744:). 6716:Ext 6708:of 6681:Tor 6650:). 6614:on 6544:on 6236:an 6093:in 6020:of 5996:of 5913:Hom 5478:of 5392:Hom 5318:of 5082:to 4834:of 4714:of 4042:↦ ( 4026:Δ: 3985:is 3949:= − 3792:of 3781:in 3769:in 3749:is 3739:+1. 3675:in 3521:of 3463:= − 3348:on 3262:is 3037:of 2930:of 2690:or 2531:in 2524:of 2465:of 2174:of 1888:of 1826:If 1657:Hom 1558:Ext 1155:to 943:of 865:to 752:of 343:of 194:to 136:on 101:on 30:In 10845:: 10428:, 10422:MR 10420:, 10410:28 10408:, 10402:, 10385:MR 10383:, 10373:, 10369:, 10355:MR 10353:, 10343:, 10339:, 10317:, 10311:, 10298:MR 10296:, 10286:, 10282:, 10263:MR 10261:, 10251:, 10230:MR 10228:, 10218:, 10214:, 10206:; 10193:MR 10191:, 10181:, 10177:, 10160:MR 10158:, 10148:, 10144:, 10103:. 9972:^ 9637:, 9220:. 9199:A 9097:: 8710:→ 8706:: 8639:: 8520:: 8157:: 8133:→ 8129:: 7985:−1 7971:−1 7951:−1 7939:, 7926:: 7832:, 7812:, 6997::= 6797:. 6776:, 6755:, 6642:↦ 6622:, 6588:. 6495:. 6425:, 6418:. 6384:. 6369:. 6197:. 6078:. 6074:− 5869:= 5862:. 5600:. 5261:. 5086:. 4757:. 4749:, 4738:. 4694:χ( 4655:. 4304:∈ 4288:∈ 4280:→ 4276:× 4272:: 4264:→ 4260:× 4256:: 4142:∈ 4126:∈ 4114:× 4106:∈ 4102:× 4078:∈ 4062:∈ 4038:, 4034:× 4030:→ 4007:RP 4005:× 4003:RP 3995:RP 3923:= 3902:≠ 3881:, 3856:= 3783:CP 3779:CP 3771:CP 3767:CP 3753:/( 3747:CP 3729:RP 3697:RP 3681:RP 3677:RP 3673:RP 3646:RP 3513:× 3465:xy 3461:yx 3457:xy 3266:/( 3189:. 2730:, 2666:, 2658:+ 2650:∩ 2504:≅ 2079:uv 2073:∪ 1954:: 1732:, 1713:0. 1185:: 947:. 901:, 797:, 785:, 775:−1 437::= 213:: 174:→ 170:: 131:∘ 117:→ 42:, 10463:e 10456:t 10449:v 10416:: 10323:. 10107:. 9713:∞ 9710:E 9701:X 9687:) 9684:X 9681:( 9672:E 9657:E 9648:. 9619:) 9616:X 9613:( 9604:u 9600:k 9580:) 9577:X 9574:( 9565:K 9544:) 9541:X 9538:( 9529:o 9525:k 9505:) 9502:X 9499:( 9490:O 9486:K 9471:. 9451:, 9448:) 9445:X 9442:( 9433:U 9429:M 9407:, 9404:) 9401:X 9398:( 9389:O 9385:S 9382:M 9362:) 9359:X 9356:( 9347:O 9343:M 9317:. 9314:) 9311:X 9308:( 9303:S 9270:. 9267:) 9264:X 9261:( 9251:S 9195:. 9193:i 9179:) 9170:A 9166:, 9157:X 9153:( 9148:i 9144:h 9127:) 9124:A 9121:, 9118:X 9115:( 9110:i 9106:h 9091:A 9089:, 9087:X 9082:α 9078:A 9076:, 9073:α 9069:X 9064:α 9060:A 9058:, 9055:α 9051:X 9047:A 9045:, 9043:X 9035:. 9033:i 9019:) 9016:B 9010:A 9007:, 9004:A 9001:( 8996:i 8992:h 8980:f 8971:) 8968:B 8965:, 8962:X 8959:( 8954:i 8950:h 8939:B 8937:, 8935:X 8931:B 8929:∩ 8927:A 8925:, 8923:A 8919:f 8915:B 8911:A 8907:X 8888:. 8879:) 8876:A 8873:, 8870:X 8867:( 8862:1 8859:+ 8856:i 8852:h 8846:d 8838:) 8835:A 8832:( 8827:i 8823:h 8811:f 8802:) 8799:X 8796:( 8791:i 8787:h 8775:g 8766:) 8763:A 8760:, 8757:X 8754:( 8749:i 8745:h 8728:A 8726:, 8724:X 8720:X 8716:g 8712:X 8708:A 8704:f 8700:A 8698:, 8696:X 8679:A 8677:( 8675:h 8671:A 8669:( 8667:h 8659:) 8657:A 8655:, 8653:X 8651:( 8649:h 8645:A 8643:( 8641:h 8637:d 8632:i 8628:h 8618:. 8616:i 8602:) 8599:A 8596:, 8593:X 8590:( 8585:i 8581:h 8574:) 8565:A 8561:, 8552:X 8548:( 8543:i 8539:h 8514:A 8512:, 8510:X 8505:α 8501:A 8499:, 8496:α 8492:X 8487:α 8483:A 8481:, 8478:α 8474:X 8470:A 8468:, 8466:X 8458:. 8456:i 8442:) 8439:B 8436:, 8433:X 8430:( 8425:i 8421:h 8409:f 8400:) 8397:B 8391:A 8388:, 8385:A 8382:( 8377:i 8373:h 8362:B 8360:, 8358:X 8354:B 8352:∩ 8350:A 8348:, 8346:A 8342:f 8338:B 8334:A 8330:X 8309:. 8300:) 8297:A 8294:( 8289:1 8283:i 8279:h 8265:) 8262:A 8259:, 8256:X 8253:( 8248:i 8244:h 8232:g 8223:) 8220:X 8217:( 8212:i 8208:h 8196:f 8187:) 8184:A 8181:( 8176:i 8172:h 8155:) 8153:A 8151:, 8149:X 8145:X 8141:g 8135:X 8131:A 8127:f 8122:A 8120:, 8118:X 8098:) 8095:B 8092:, 8089:Y 8086:( 8080:) 8077:A 8074:, 8071:X 8068:( 8065:: 8062:g 8042:) 8039:B 8036:, 8033:Y 8030:( 8024:) 8021:A 8018:, 8015:X 8012:( 8009:: 8006:f 7989:A 7987:( 7983:i 7979:h 7975:A 7973:( 7969:i 7965:h 7957:) 7955:A 7953:( 7949:i 7945:h 7941:A 7937:X 7935:( 7932:i 7928:h 7923:i 7920:∂ 7913:A 7909:X 7905:A 7901:X 7899:( 7889:i 7884:i 7880:h 7861:i 7857:P 7855:( 7853:H 7849:P 7780:) 7777:E 7774:( 7769:n 7765:H 7758:) 7755:X 7752:( 7747:n 7743:H 7736:) 7733:Z 7730:( 7725:n 7721:H 7714:) 7711:) 7708:X 7705:( 7700:Z 7696:l 7692:B 7689:( 7684:n 7680:H 7656:Z 7627:) 7624:X 7621:( 7616:1 7613:+ 7610:n 7606:H 7599:) 7596:E 7593:( 7588:n 7584:H 7577:) 7574:) 7571:X 7568:( 7563:Z 7559:l 7555:B 7552:( 7547:n 7543:H 7536:) 7533:Z 7530:( 7525:n 7521:H 7514:) 7511:X 7508:( 7503:n 7499:H 7462:X 7452:Z 7432:) 7429:X 7426:( 7421:Z 7417:l 7413:B 7403:E 7376:X 7370:Z 7350:2 7320:) 7315:q 7310:F 7305:( 7302:X 7262:) 7258:C 7254:( 7251:X 7227:) 7221:) 7215:k 7211:f 7207:, 7201:, 7196:1 7192:f 7187:( 7181:] 7175:n 7171:x 7167:, 7161:, 7156:0 7152:x 7147:[ 7142:Z 7135:( 7126:= 7123:X 7090:Q 7076:Z 7066:) 7063:) 7058:n 7050:( 7046:/ 7041:Z 7037:; 7034:X 7031:( 7026:k 7021:t 7018:e 7014:H 6994:) 6984:Q 6979:; 6976:X 6973:( 6968:k 6964:H 6940:p 6894:p 6870:p 6845:n 6840:P 6814:0 6795:X 6791:Z 6786:X 6782:Z 6778:E 6773:X 6769:Z 6765:E 6763:, 6761:X 6759:( 6757:H 6753:X 6749:E 6742:N 6740:, 6738:M 6736:( 6733:R 6728:N 6726:, 6724:M 6722:( 6719:R 6710:R 6706:N 6702:R 6699:⊗ 6697:M 6693:N 6691:, 6689:M 6687:( 6684:i 6675:R 6667:X 6655:X 6648:X 6646:( 6644:E 6640:E 6628:X 6626:( 6624:E 6620:X 6616:X 6612:E 6608:X 6600:X 6570:X 6566:X 6562:A 6560:, 6558:X 6556:( 6554:H 6550:A 6546:X 6538:i 6534:E 6532:, 6530:X 6528:( 6526:H 6522:X 6518:E 6382:X 6378:X 6374:i 6367:M 6346:, 6343:) 6340:M 6337:( 6332:n 6326:j 6323:+ 6320:i 6316:H 6309:) 6306:M 6303:( 6298:j 6294:H 6287:) 6284:M 6281:( 6276:i 6272:H 6258:n 6254:j 6250:i 6242:j 6238:i 6234:M 6230:n 6195:X 6181:) 6178:R 6175:, 6172:X 6169:( 6164:i 6158:n 6154:H 6140:) 6137:R 6134:, 6131:X 6128:( 6123:i 6119:H 6108:R 6106:, 6104:X 6102:( 6099:n 6095:H 6087:n 6083:X 6076:i 6072:j 6068:Z 6064:Y 6060:R 6058:, 6056:X 6054:( 6051:i 6049:− 6047:j 6043:H 6039:R 6037:, 6035:X 6033:( 6030:j 6026:H 6022:X 6018:Z 6014:j 6010:R 6008:, 6006:X 6004:( 6002:H 5998:X 5994:Y 5990:i 5986:X 5979:R 5962:, 5959:) 5956:R 5953:, 5950:) 5947:R 5944:, 5941:X 5938:( 5933:i 5929:H 5925:( 5917:R 5906:) 5903:R 5900:, 5897:X 5894:( 5889:i 5885:H 5871:j 5867:i 5860:X 5856:X 5839:) 5836:R 5833:, 5830:X 5827:( 5818:H 5811:) 5808:R 5805:, 5802:X 5799:( 5790:H 5783:) 5780:R 5777:, 5774:X 5771:( 5762:H 5748:R 5744:j 5740:i 5723:) 5720:R 5717:, 5714:X 5711:( 5706:i 5700:j 5696:H 5689:) 5686:R 5683:, 5680:X 5677:( 5672:j 5668:H 5661:) 5658:R 5655:, 5652:X 5649:( 5644:i 5640:H 5636:: 5616:X 5598:X 5584:) 5581:2 5577:/ 5572:Z 5568:, 5565:X 5562:( 5557:1 5553:H 5546:0 5536:X 5522:) 5519:2 5515:/ 5510:Z 5506:, 5503:X 5500:( 5495:1 5491:H 5480:X 5462:) 5459:X 5456:( 5451:1 5426:) 5423:A 5420:, 5417:) 5414:X 5411:( 5406:1 5398:( 5372:) 5369:A 5366:, 5363:X 5360:( 5355:1 5351:H 5340:X 5336:X 5330:A 5324:A 5320:X 5302:) 5299:A 5296:, 5293:X 5290:( 5285:1 5281:H 5270:X 5266:A 5247:1 5243:S 5236:X 5214:1 5210:S 5199:u 5185:) 5181:Z 5177:, 5174:X 5171:( 5166:1 5162:H 5139:1 5135:S 5114:) 5111:1 5108:, 5104:Z 5100:( 5097:K 5084:Y 5080:X 5066:] 5063:Y 5060:, 5057:X 5054:[ 5044:X 5027:) 5024:A 5021:, 5018:X 5015:( 5010:j 5006:H 4986:] 4983:) 4980:j 4977:, 4974:A 4971:( 4968:K 4965:, 4962:X 4959:[ 4946:u 4932:) 4929:j 4926:, 4923:A 4920:( 4917:K 4911:X 4901:u 4897:X 4893:j 4879:) 4876:A 4873:, 4870:) 4867:j 4864:, 4861:A 4858:( 4855:K 4852:( 4847:j 4843:H 4832:u 4820:A 4816:j 4802:) 4799:j 4796:, 4793:A 4790:( 4787:K 4777:j 4773:A 4736:X 4732:r 4728:X 4724:X 4720:E 4716:E 4708:Z 4706:, 4704:X 4702:( 4700:H 4696:E 4686:X 4682:X 4678:r 4674:E 4653:Z 4649:Z 4645:Z 4643:, 4641:X 4639:( 4637:H 4629:F 4627:, 4625:X 4623:( 4621:H 4617:F 4615:, 4613:X 4611:( 4609:H 4605:i 4584:F 4578:) 4575:F 4572:, 4569:X 4566:( 4561:n 4557:H 4550:) 4547:F 4544:, 4541:X 4538:( 4533:i 4527:n 4523:H 4516:) 4513:F 4510:, 4507:X 4504:( 4499:i 4495:H 4481:F 4477:F 4475:, 4473:X 4471:( 4469:H 4465:F 4461:n 4453:X 4426:. 4423:) 4420:R 4417:, 4414:Y 4408:X 4405:( 4400:j 4397:+ 4394:i 4390:H 4383:) 4380:) 4377:v 4374:( 4365:g 4361:( 4358:) 4355:) 4352:u 4349:( 4340:f 4336:( 4333:= 4330:v 4324:u 4314:R 4312:, 4310:Y 4308:( 4306:H 4302:v 4298:R 4296:, 4294:X 4292:( 4290:H 4286:u 4282:Y 4278:Y 4274:X 4270:g 4266:X 4262:Y 4258:X 4254:f 4250:Y 4246:X 4230:. 4227:) 4224:R 4221:, 4218:X 4215:( 4210:j 4207:+ 4204:i 4200:H 4193:) 4190:v 4184:u 4181:( 4168:= 4165:v 4162:u 4152:R 4150:, 4148:X 4146:( 4144:H 4140:v 4136:R 4134:, 4132:X 4130:( 4128:H 4124:u 4120:R 4118:, 4116:Y 4112:X 4110:( 4108:H 4104:v 4100:u 4088:R 4086:, 4084:Y 4082:( 4080:H 4076:v 4072:R 4070:, 4068:X 4066:( 4064:H 4060:u 4056:Y 4052:X 4048:x 4046:, 4044:x 4040:x 4036:X 4032:X 4028:X 4011:Z 3999:Z 3991:Z 3987:Z 3983:R 3979:R 3977:, 3975:X 3973:( 3971:H 3967:R 3963:x 3959:x 3954:. 3951:P 3946:i 3942:A 3938:i 3934:B 3929:i 3925:P 3920:i 3916:B 3912:i 3908:A 3904:j 3900:i 3895:j 3891:B 3887:i 3883:A 3879:j 3875:i 3870:j 3866:B 3862:i 3858:B 3853:j 3849:A 3845:i 3841:A 3837:P 3832:g 3828:B 3824:1 3821:B 3816:g 3812:A 3808:1 3805:A 3801:Z 3797:g 3790:X 3785:. 3775:x 3763:x 3759:x 3755:x 3751:Z 3737:a 3733:Z 3725:Z 3721:a 3717:i 3713:y 3709:Z 3705:Z 3701:y 3693:Z 3689:Z 3685:j 3666:x 3662:x 3658:x 3654:Z 3650:Z 3627:. 3624:) 3621:R 3618:, 3615:Y 3612:( 3603:H 3597:R 3589:) 3586:R 3583:, 3580:X 3577:( 3568:H 3561:) 3558:R 3555:, 3552:Y 3546:X 3543:( 3534:H 3523:R 3515:Y 3511:X 3500:Y 3496:R 3492:R 3490:, 3488:X 3486:( 3484:H 3480:Y 3476:X 3472:R 3453:y 3449:x 3443:Z 3437:S 3421:2 3417:) 3411:1 3407:S 3403:( 3393:P 3391:, 3389:P 3385:Q 3369:1 3365:S 3354:P 3350:n 3346:Z 3326:n 3322:) 3316:1 3312:S 3308:( 3292:x 3288:n 3284:x 3268:x 3264:Z 3248:n 3244:S 3230:n 3217:. 3215:R 3207:Z 3199:Z 3187:M 3183:N 3179:N 3175:X 3161:) 3158:] 3155:N 3152:[ 3149:( 3140:f 3119:. 3116:) 3113:N 3110:( 3105:1 3098:f 3091:X 3071:) 3068:] 3065:N 3062:[ 3059:( 3050:f 3039:X 3025:) 3022:N 3019:( 3014:1 3007:f 2986:) 2983:X 2980:( 2975:i 2971:H 2964:) 2961:] 2958:N 2955:[ 2952:( 2943:f 2932:M 2928:N 2924:i 2920:M 2916:X 2912:f 2898:) 2895:X 2892:( 2887:i 2883:H 2872:X 2868:X 2864:i 2850:) 2847:X 2844:( 2839:i 2835:H 2824:X 2816:p 2808:p 2794:p 2790:/ 2785:Z 2763:Z 2744:X 2736:X 2728:X 2716:X 2712:X 2708:X 2700:X 2696:X 2692:T 2688:S 2684:T 2680:S 2672:X 2668:T 2664:S 2660:j 2656:i 2652:T 2648:S 2634:, 2631:) 2628:X 2625:( 2620:j 2617:+ 2614:i 2610:H 2603:] 2600:T 2594:S 2591:[ 2588:= 2585:] 2582:T 2579:[ 2576:] 2573:S 2570:[ 2556:j 2552:i 2548:T 2544:S 2540:X 2537:H 2533:X 2529:i 2522:S 2518:X 2514:i 2512:− 2510:n 2506:H 2502:X 2499:H 2491:n 2483:X 2475:M 2471:N 2467:M 2459:M 2455:N 2435:- 2433:R 2419:) 2416:R 2413:, 2410:X 2407:( 2398:H 2391:) 2388:R 2385:, 2382:Y 2379:( 2370:H 2366:: 2357:f 2333:, 2330:Y 2324:X 2318:f 2296:. 2293:) 2290:R 2287:, 2284:X 2281:( 2276:j 2272:H 2265:v 2262:, 2259:) 2256:R 2253:, 2250:X 2247:( 2242:i 2238:H 2231:u 2227:, 2224:u 2221:v 2216:j 2213:i 2209:) 2205:1 2199:( 2196:= 2193:v 2190:u 2176:X 2152:) 2149:R 2146:, 2143:X 2140:( 2135:i 2131:H 2125:i 2117:= 2114:) 2111:R 2108:, 2105:X 2102:( 2093:H 2075:v 2071:u 2067:v 2063:u 2049:, 2046:) 2043:R 2040:, 2037:X 2034:( 2029:j 2026:+ 2023:i 2019:H 2012:) 2009:R 2006:, 2003:X 2000:( 1995:j 1991:H 1984:) 1981:R 1978:, 1975:X 1972:( 1967:i 1963:H 1942:R 1938:X 1932:. 1930:i 1922:R 1920:, 1918:X 1916:( 1914:H 1910:R 1902:R 1894:X 1890:X 1882:i 1868:) 1865:A 1862:, 1859:X 1856:( 1851:i 1847:H 1828:X 1823:. 1811:) 1808:F 1805:, 1802:X 1799:( 1794:i 1790:H 1762:) 1759:F 1756:, 1753:X 1750:( 1745:i 1741:H 1730:F 1707:) 1704:A 1701:, 1698:) 1694:Z 1690:, 1687:X 1684:( 1679:i 1675:H 1671:( 1662:Z 1650:) 1647:A 1644:, 1641:X 1638:( 1633:i 1629:H 1622:) 1619:A 1616:, 1613:) 1609:Z 1605:, 1602:X 1599:( 1591:1 1585:i 1581:H 1577:( 1569:1 1563:Z 1551:0 1512:) 1509:Y 1506:, 1503:X 1500:( 1495:1 1492:+ 1489:i 1485:H 1478:) 1475:Y 1472:( 1467:i 1463:H 1456:) 1453:X 1450:( 1445:i 1441:H 1434:) 1431:Y 1428:, 1425:X 1422:( 1417:i 1413:H 1396:X 1392:Y 1375:) 1372:A 1369:; 1366:Y 1363:, 1360:X 1357:( 1352:i 1348:H 1315:) 1312:X 1309:( 1304:1 1301:+ 1298:i 1294:H 1287:) 1284:V 1278:U 1275:( 1270:i 1266:H 1259:) 1256:V 1253:( 1248:i 1244:H 1237:) 1234:U 1231:( 1226:i 1222:H 1215:) 1212:X 1209:( 1204:i 1200:H 1179:V 1175:U 1168:X 1157:Y 1153:X 1142:R 1124:) 1121:X 1118:( 1113:i 1109:H 1102:) 1099:Y 1096:( 1091:i 1087:H 1083:: 1074:f 1049:) 1046:Y 1043:( 1038:i 1034:H 1027:) 1024:X 1021:( 1016:i 1012:H 1008:: 999:f 974:Y 968:X 965:: 962:f 941:Z 935:- 933:R 929:R 922:A 918:A 903:A 899:X 897:( 895:H 891:d 887:d 875:d 871:d 867:A 863:X 859:i 855:X 851:i 847:A 841:i 818:i 814:C 803:i 799:A 795:X 793:( 791:H 787:A 783:X 781:( 779:H 773:i 769:d 764:i 762:d 758:A 754:X 747:i 743:i 714:1 708:i 704:C 694:1 688:i 684:d 664:i 660:C 647:i 643:d 623:1 620:+ 617:i 613:C 581:. 571:i 567:C 553:1 547:i 543:C 539:: 534:1 528:i 524:d 498:i 473:, 470:) 467:A 464:, 459:i 455:C 451:( 447:m 444:o 441:H 427:i 423:C 408:i 406:C 402:A 395:i 390:i 386:C 382:i 377:i 372:X 368:i 364:X 360:i 351:i 349:C 345:X 319:1 313:i 309:C 296:i 277:i 273:C 263:1 260:+ 257:i 238:1 235:+ 232:i 228:C 207:X 196:Y 192:X 188:X 184:Y 176:Y 172:X 168:f 138:X 133:f 129:F 124:f 119:Y 115:X 111:f 103:Y 99:F 95:Y 91:X 20:)

Index

Cohomology class
mathematics
homology theory
algebraic topology
abelian groups
topological space
cochain complex
functions
chains
topology
geometry
algebra
contravariant
pullbacks
mapping
cup product
ring
graded-commutative ring
continuous map
homomorphism
homotopy groups
singular chain complex
singular homology
free abelian group
dual group
dual homomorphism
cochain complex
equivalence classes
commutative ring
modules

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