Knowledge (XXG)

Connected space

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As a consequence, a notion of connectedness can be formulated independently of the topology on a space. To wit, there is a category of connective spaces consisting of sets with collections of connected subsets satisfying connectivity axioms; their morphisms are those functions which map connected
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Continuous image of arc-connected space may not be arc-connected: for example, a quotient map from an arc-connected space to its quotient with countably many (at least 2) topologically distinguishable points cannot be arc-connected due to too small
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of the original space. It follows that, in the case where their number is finite, each component is also an open subset. However, if their number is infinite, this might not be the case; for instance, the connected components of the set of the
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is, by definition, also required to be path connected, any simply connected space is also connected. If the "path connectedness" requirement is dropped from the definition of simple connectivity, a simply connected space does not need to be
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Locally connected does not imply connected, nor does locally path-connected imply path connected. A simple example of a locally connected (and locally path-connected) space that is not connected (or path-connected) is the union of two
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have path connected subsets, namely those subsets for which every pair of points has a path of edges joining them. But it is not always possible to find a topology on the set of points which induces the same connected sets. The
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is connected, but is not simply connected. The three-dimensional Euclidean space without the origin is connected, and even simply connected. In contrast, the one-dimensional Euclidean space without the origin is not
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An example of a space that is not connected is a plane with an infinite line deleted from it. Other examples of disconnected spaces (that is, spaces which are not connected) include the plane with an
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real, invertible matrices) consists of two connected components: the one with matrices of positive determinant and the other of negative determinant. In particular, it is not connected. In contrast,
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if it has a base of path-connected sets. An open subset of a locally path-connected space is connected if and only if it is path-connected. This generalizes the earlier statement about
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of a connected (resp. locally connected, path-connected, locally path-connected) space is connected (resp. locally connected, path-connected, locally path-connected).
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Every path-connected space is connected. The converse is not always true: examples of connected spaces that are not path-connected include the extended
6464: 1741:, is totally disconnected. However, by considering the two copies of zero, one sees that the space is not totally separated. In fact, it is not even 1715:. Clearly, any totally separated space is totally disconnected, but the converse does not hold. For example, take two copies of the rational numbers 5610:
However, every graph can be canonically made into a topological space, by treating vertices as points and edges as copies of the unit interval (see
3165:) if there is exactly one path-component. For non-empty spaces, this is equivalent to the statement that there is a path joining any two points in 5607:). Topological spaces and graphs are special cases of connective spaces; indeed, the finite connective spaces are precisely the finite graphs. 2619: 5614:). Then one can show that the graph is connected (in the graph theoretical sense) if and only if it is connected as a topological space. 5506:
The connected components of a space are disjoint unions of the path-connected components (which in general are neither open nor closed).
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If arc-connected subsets have a non-empty intersection, then their union may not be arc-connected. For example, the arc-components of
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Every open subset of a locally connected (resp. locally path-connected) space is locally connected (resp. locally path-connected).
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are connected if and only if they are path-connected. Additionally, connectedness and path-connectedness are the same for
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In general, any path connected space must be connected but there exist connected spaces that are not path connected. The
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of a topological space is said to be connected if it is connected under its subspace topology. Some authors exclude the
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Each ellipse is a connected set, but the union is not connected, since it can be partitioned to two disjoint open sets
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of a connected subset is connected. Furthermore, any subset between a connected subset and its closure is connected.
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can be partitioned to two sub-collections, such that the unions of the sub-collections are disjoint and open in
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is connected. More generally, the set of invertible bounded operators on a complex Hilbert space is connected.
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Arc-components of a product space may not be products of arc-components of the marginal spaces. For example,
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is totally disconnected; since the set contains uncountably many points, it has uncountably many components.
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Arc-wise connected space is path connected, but path-wise connected space may not be arc-wise connected
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A Euclidean plane with a straight line removed is not connected since it consists of two half-planes.
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Historically this modern formulation of the notion of connectedness (in terms of no partition of
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is closed. An example of a space which is path-connected but not arc-connected is given by the
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is an example of a set that is connected but is neither path connected nor locally connected.
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of a family of connected (resp. path-connected) spaces is connected (resp. path-connected).
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Intuition for path-connected spaces does not readily transfer to arc-connected spaces. Let
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A classical example of a connected space that is not locally connected is the so-called
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Arc-connected product space may not be a product of arc-connected spaces. For example,
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is not connected. So it can be written as the union of two disjoint open sets, e.g.
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If the sets can be ordered as a "linked chain", i.e. indexed by integer indices and
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is disconnected; both of these intervals are open in the standard topological space
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On the other hand, a finite set might be connected. For example, the spectrum of a
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is connected, that is, it cannot be divided into two disjoint non-empty open sets.
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and integral domains are connected. More generally, the following are equivalent
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A locally path-connected space is path-connected if and only if it is connected.
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that is path-connected is also arc-connected; more generally this is true for a
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In a locally path-connected space, every open connected set is path-connected.
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of connected sets is not necessarily connected, as can be seen by considering
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Wilder, R.L. (1978). "Evolution of the Topological Concept of "Connected"".
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is connected, it must be entirely contained in one of these components, say
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is a stronger notion of connectedness, requiring the structure of a path. A
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is (path-)connected. This result can be considered a generalization of the
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If there exist no two disjoint non-empty open sets in a topological space
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the union of any collection of connected subsets such that each contained
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into two separated sets) first appeared (independently) with N.J. Lennes,
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The topologist's sine curve is connected, but it is not locally connected
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is locally connected if and only if every component of every open set of
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is connected; although it can, for example, be written as the union of
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is disconnected (and thus can be written as a union of two open sets
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The connected components of a locally connected space are also open.
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with at least two elements is disconnected, in fact such a space is
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if it is the union of two disjoint non-empty open sets. Otherwise,
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Continuous image of arc-wise connected set is arc-wise connected.
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remains simply connected after removal of countably many points.
944:), which are not open. Proof: Any two distinct rational numbers 6054: 3893:, each of which is locally path-connected. More generally, any 2394:
consists of two points and is connected. It is an example of a
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Yet stronger versions of connectivity include the notion of a
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A space in which all components are one-point sets is called
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of connected sets is not necessarily connected. However, if
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at the beginning of the 20th century. See for details.
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Every locally path-connected space is locally connected.
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The two sets in the last union are disjoint and open in
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Pages displaying short descriptions of redirect targets
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furnishes such an example, as does the above-mentioned
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If the intersection of each pair of sets is not empty (
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are in different components. Take an irrational number
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Examples of unions and intersections of connected sets
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of the space. The components of any topological space
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Mem. Fac. Sci. Eng. Shimane Univ., Series B: Math. Sc
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topological graph theory#Graphs as topological spaces
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If the common intersection of all sets is not empty (
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removed, as well as the union of two disjoint closed
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the second set is not open in the chosen topology of
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Two connected sets whose difference is not connected
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is not a product of two rings in a nontrivial way).
2578:{\displaystyle \operatorname {GL} (n,\mathbb {C} )} 2498:{\displaystyle \operatorname {GL} (n,\mathbb {R} )} 5662: 5642: 5591: 5565: 5462: 5433: 5413: 5381: 5361: 5320: 5300: 5280: 5260: 5077: 5050: 5023: 4996: 4976: 4917: 4877: 4857: 4824: 4804: 4777: 4750: 4724: 4690: 4646: 4598: 4568: 4521: 4457: 4389: 4345: 4325: 4292: 4269: 4249: 4226: 4143: 4107: 3977: 3927: 3885: 3856: 3816: 3796: 3768: 3748: 3707: 3684: 3664: 3633: 3613: 3582: 3550: 3527: 3497: 3469: 3449: 3425: 3362: 3330: 3301: 3272: 3242: 3210: 3177: 3154: 3124: 3104: 3084: 3064: 3044: 3020: 2996: 2968: 2933: 2898: 2878: 2843: 2823: 2800: 2780: 2708: 2688: 2656: 2634: 2607: 2577: 2537: 2517: 2497: 2444: 2420: 2364: 2342: 2305: 2276: 2250: 2221: 2192: 2156: 2128: 2082: 2046: 2001: 1948: 1921: 1887: 1852: 1817: 1778: 1729: 1707: 1687: 1667: 1647: 1627: 1607: 1587: 1564: 1544: 1524: 1496: 1458: 1438: 1395: 1368: 1344: 1314: 1291: 1271: 1241: 1189: 1164: 1132: 1077: 1025: 976: 919: 895: 879:) of a non-empty topological space are called the 871: 844: 821: 801: 781: 758: 738: 718: 695: 675: 652: 616: 588: 556: 524: 493: 471: 447: 424: 400: 377: 354: 319: 291: 252: 220: 188: 5898:The K-book: An introduction to algebraic K-theory 3570:Arc-components may not be disjoint. For example, 173:that are used to distinguish topological spaces. 4171:of connected sets is not necessarily connected. 3784:of connected sets. It can be shown that a space 3715:intersect, but their union is not arc-connected. 3185:. Again, many authors exclude the empty space. 2730:, where all examples of this paragraph bear the 501:cannot be written as the union of two non-empty 5932:"How to prove this result about connectedness?" 3776:contains a connected open neighbourhood. It is 3254:they are path-connected; these subsets are the 1439:{\displaystyle \Gamma _{x}\subset \Gamma '_{x}} 1133:{\displaystyle B=\{q\in \mathbb {Q} :q>r\}.} 5622:There are stronger forms of connectedness for 5604: 3535:can be connected by a path but not by an arc. 1078:{\displaystyle A=\{q\in \mathbb {Q} :q<r\}} 6066: 4698:are disjoint and open in the quotient space). 4654:is a separation of the quotient space (since 3827:Similarly, a topological space is said to be 8: 5871:Introduction to Topology and Modern Analysis 4832:with each such component is connected (i.e. 4563: 4550: 4320: 4307: 4023: 4005: 2734:induced by two-dimensional Euclidean space. 2041: 2035: 1124: 1098: 1072: 1046: 703:will once again be a connected subset. The 583: 571: 551: 539: 204:if it is a connected space when viewed as a 4977:{\displaystyle Y\cup X_{1}=Z_{1}\cup Z_{2}} 4529:, then again their union must be connected. 1466:is compact Hausdorff or locally connected. 6434: 6407: 6073: 6059: 6051: 4532:If the sets are pairwise-disjoint and the 1249:. Thus each component is a one-point set. 789:it is the unique largest (with respect to 5873:. McGraw Hill Book Company. p. 144. 5655: 5635: 5578: 5558: 5446: 5426: 5394: 5374: 5354: 5313: 5293: 5273: 5247: 5234: 5211: 5198: 5180: 5162: 5149: 5131: 5113: 5090: 5069: 5063: 5042: 5036: 5015: 5009: 4989: 4968: 4955: 4942: 4930: 4909: 4897: 4870: 4849: 4837: 4817: 4796: 4790: 4769: 4763: 4737: 4711: 4659: 4615: 4585: 4557: 4545: 4540: 4501: 4488: 4473: 4443: 4430: 4409: 4390:{\textstyle \bigcap X_{i}\neq \emptyset } 4375: 4366: 4338: 4314: 4305: 4285: 4262: 4242: 4183: 4135: 4131: 4130: 4127: 4055: 3997: 3940: 3921: 3920: 3918: 3877: 3873: 3872: 3869: 3848: 3844: 3843: 3840: 3809: 3789: 3761: 3741: 3700: 3677: 3658: 3657: 3649: 3626: 3607: 3606: 3598: 3575: 3543: 3520: 3507:, which is a space where each image of a 3490: 3462: 3442: 3394: 3355: 3322: 3318: 3317: 3314: 3293: 3289: 3288: 3285: 3266: 3265: 3263: 3236: 3235: 3233: 3202: 3196: 3170: 3147: 3145: 3117: 3097: 3077: 3057: 3037: 3013: 2989: 2946: 2911: 2891: 2859: 2836: 2816: 2793: 2773: 2701: 2672: 2649: 2627: 2600: 2568: 2567: 2550: 2530: 2510: 2488: 2487: 2470: 2437: 2413: 2358: 2357: 2355: 2336: 2335: 2333: 2297: 2293: 2292: 2289: 2263: 2234: 2213: 2209: 2208: 2205: 2186: 2185: 2183: 2150: 2149: 2147: 2106: 2074: 2070: 2069: 2066: 2015: 1961: 1929: 1902: 1865: 1830: 1798: 1759: 1723: 1722: 1720: 1700: 1680: 1660: 1640: 1620: 1600: 1580: 1557: 1537: 1517: 1489: 1451: 1427: 1414: 1408: 1385: 1361: 1333: 1327: 1304: 1284: 1263: 1257: 1227: 1208: 1202: 1180: 1179: 1177: 1145: 1108: 1107: 1090: 1056: 1055: 1038: 1014: 995: 989: 968: 955: 949: 912: 888: 864: 834: 814: 794: 771: 751: 746:is the union of all connected subsets of 731: 711: 688: 665: 645: 609: 569: 537: 517: 486: 464: 440: 417: 393: 370: 362:the following conditions are equivalent: 347: 312: 284: 245: 231:Some related but stronger conditions are 213: 181: 5477:Every path-connected space is connected. 3899: 596:is the two-point space endowed with the 169:. Connectedness is one of the principal 35:Connected and disconnected subspaces of 5784: 4742: 2178:If even a single point is removed from 232: 5755: â€“ Property of topological spaces 4357:necessarily connected. In particular: 2168:with the usual topology, is connected. 5909:Brandsma, Henno (February 13, 2013). 4300:is disconnected, then the collection 3457:is a maximal arc-connected subset of 1242:{\displaystyle q_{1}\in A,q_{2}\in B} 7: 5496:The connected components are always 3665:{\displaystyle X\times \mathbb {R} } 3614:{\displaystyle X\times \mathbb {R} } 2620:finitely generated projective module 1484:. Related to this property, a space 1026:{\displaystyle q_{1}<r<q_{2},} 5441:is (path-)connected then the image 3590:has two overlapping arc-components. 2595:The spectrum of a commutative ring 27:Topological space that is connected 5727:Connected component (graph theory) 4516: 4475: 4452: 4411: 4384: 3730:A topological space is said to be 3492: 2328:, over a connected field (such as 1512:if, for any two distinct elements 1424: 1411: 1330: 1260: 155:that cannot be represented as the 25: 4580:must be connected. Otherwise, if 4227:{\displaystyle X=(0,1)\cup (1,2)} 6465:Properties of topological spaces 6433: 6406: 6396: 6386: 6375: 6365: 6364: 6158: 5711: 5414:{\displaystyle f:X\rightarrow Y} 4144:{\displaystyle \mathbb {R} ^{2}} 3886:{\displaystyle \mathbb {C} ^{n}} 3857:{\displaystyle \mathbb {R} ^{n}} 3672:has a single arc-component, but 3331:{\displaystyle \mathbb {C} ^{n}} 3302:{\displaystyle \mathbb {R} ^{n}} 3148: 2306:{\displaystyle \mathbb {R} ^{n}} 2222:{\displaystyle \mathbb {R} ^{n}} 2083:{\displaystyle \mathbb {R} ^{n}} 408:which are both open and closed ( 176:A subset of a topological space 45: 6015:Muscat, J; Buhagiar, D (2006). 5618:Stronger forms of connectedness 3978:{\displaystyle (0,1)\cup (2,3)} 2383:. The simplest example is the 2258:the remainder is connected. If 2047:{\displaystyle (0,1)\cup \{3\}} 5741:Domain (mathematical analysis) 5457: 5451: 5405: 5389:be topological spaces and let 5308:, contradicting the fact that 5288:, so there is a separation of 4685: 4679: 4670: 4664: 4641: 4635: 4626: 4620: 4280:This means that, if the union 4221: 4209: 4203: 4191: 4097: 4085: 4020: 4008: 3972: 3960: 3954: 3942: 3417: 3414: 3402: 2957: 2951: 2922: 2916: 2873: 2861: 2572: 2558: 2492: 2478: 2120: 2108: 2029: 2017: 1993: 1981: 1975: 1963: 1943: 1931: 1916: 1904: 1879: 1867: 1844: 1832: 1812: 1800: 1773: 1761: 1279:be the connected component of 1159: 1147: 977:{\displaystyle q_{1}<q_{2}} 856:connected subsets (ordered by 705:connected component of a point 52:From top to bottom: red space 1: 5794:American Mathematical Monthly 5769: â€“ Type of uniform space 5747:Extremally disconnected space 5421:be a continuous function. If 5347:Main theorem of connectedness 4647:{\displaystyle q(U)\cup q(V)} 3380:topologically distinguishable 2090:is connected; it is actually 1190:{\displaystyle \mathbb {Q} ,} 5670:must be connected, and thus 4751:{\displaystyle X\setminus Y} 4725:{\displaystyle X\supseteq Y} 3928:{\displaystyle \mathbb {R} } 3273:{\displaystyle \mathbb {R} } 3243:{\displaystyle \mathbb {R} } 3155:{\displaystyle \mathbf {0} } 2365:{\displaystyle \mathbb {C} } 2343:{\displaystyle \mathbb {R} } 2193:{\displaystyle \mathbb {R} } 2157:{\displaystyle \mathbb {R} } 1730:{\displaystyle \mathbb {Q} } 1446:where the equality holds if 1345:{\displaystyle \Gamma _{x}'} 262:. Another related notion is 6004:Encyclopedia of Mathematics 5930:Marek (February 13, 2013). 4918:{\displaystyle Y\cup X_{1}} 4858:{\displaystyle Y\cup X_{i}} 4569:{\displaystyle X/\{X_{i}\}} 3897:is locally path-connected. 3382:points can be joined by an 2588:The spectra of commutative 2432:to a connected space, then 1352:be the intersection of all 1272:{\displaystyle \Gamma _{x}} 6481: 6327:Banach fixed-point theorem 5605:Muscat & Buhagiar 2006 5599:odd) is one such example. 5530:is locally path-connected. 5472:intermediate value theorem 4892:By contradiction, suppose 3756:if every neighbourhood of 3723: 2377:discrete topological space 872:{\displaystyle \subseteq } 802:{\displaystyle \subseteq } 6360: 6156: 5767:Uniformly connected space 5500:(but in general not open) 4691:{\displaystyle q(U),q(V)} 4326:{\displaystyle \{X_{i}\}} 3340:finite topological spaces 2831:is a continuous function 5997:V. I. Malykhin (2001) , 5961:Topology, Second Edition 5841:Stephen Willard (1970). 5603:sets to connected sets ( 3280:. Also, open subsets of 3072:if there is a path from 2689:{\displaystyle \neq 0,1} 2385:discrete two-point space 2318:topological vector space 2251:{\displaystyle n\geq 2,} 940:are the one-point sets ( 342:For a topological space 143:and related branches of 5753:Locally connected space 5699:topologist's sine curve 4599:{\displaystyle U\cup V} 3990:topologist's sine curve 3726:Locally connected space 3692:has two arc-components. 3498:{\displaystyle \Delta } 3426:{\displaystyle f:\to X} 3220:topologist's sine curve 2505:(that is, the group of 2457:topologist's sine curve 2392:discrete valuation ring 2372:), is simply connected. 2277:{\displaystyle n\geq 3} 1572:, there exist disjoint 1299:in a topological space 660:in a topological space 589:{\displaystyle \{0,1\}} 557:{\displaystyle \{0,1\}} 6382:Mathematics portal 6282:Metrics and properties 6268:Second-countable space 6030:: 1–13. Archived from 5845:. Dover. p. 191. 5679:simply connected space 5664: 5644: 5593: 5592:{\displaystyle n>3} 5567: 5464: 5435: 5415: 5383: 5363: 5337: 5322: 5302: 5282: 5262: 5079: 5052: 5025: 4998: 4978: 4919: 4879: 4859: 4826: 4806: 4779: 4752: 4726: 4692: 4648: 4600: 4570: 4523: 4459: 4391: 4347: 4327: 4294: 4271: 4251: 4228: 4164: 4145: 4109: 3979: 3929: 3905: 3887: 3858: 3831:locally path-connected 3818: 3798: 3770: 3750: 3709: 3686: 3666: 3635: 3621:is arc-connected, but 3615: 3584: 3552: 3529: 3499: 3471: 3451: 3427: 3364: 3332: 3303: 3274: 3244: 3212: 3179: 3156: 3126: 3106: 3086: 3066: 3046: 3022: 2998: 2970: 2969:{\displaystyle f(1)=y} 2935: 2934:{\displaystyle f(0)=x} 2900: 2880: 2845: 2825: 2802: 2782: 2751: 2710: 2690: 2658: 2636: 2609: 2579: 2539: 2519: 2499: 2446: 2422: 2366: 2344: 2307: 2278: 2252: 2223: 2194: 2158: 2130: 2129:{\displaystyle (0,0),} 2101:excluding the origin, 2084: 2048: 2003: 1950: 1923: 1889: 1888:{\displaystyle [0,2).} 1854: 1853:{\displaystyle [1,2),} 1819: 1780: 1731: 1709: 1689: 1669: 1649: 1629: 1609: 1589: 1566: 1546: 1526: 1498: 1460: 1440: 1397: 1370: 1346: 1316: 1293: 1273: 1243: 1191: 1166: 1134: 1079: 1027: 978: 921: 897: 873: 846: 823: 809:) connected subset of 803: 783: 760: 740: 720: 697: 677: 654: 618: 590: 558: 526: 495: 473: 449: 426: 402: 379: 356: 321: 293: 254: 222: 190: 171:topological properties 72:, whereas green space 5672:hyperconnected spaces 5665: 5645: 5594: 5568: 5465: 5436: 5416: 5384: 5364: 5335: 5323: 5303: 5283: 5263: 5080: 5078:{\displaystyle X_{1}} 5053: 5051:{\displaystyle Z_{2}} 5026: 5024:{\displaystyle Z_{1}} 4999: 4979: 4920: 4880: 4865:is connected for all 4860: 4827: 4812:), then the union of 4807: 4805:{\displaystyle X_{2}} 4780: 4778:{\displaystyle X_{1}} 4753: 4732:and their difference 4727: 4693: 4649: 4601: 4571: 4524: 4460: 4392: 4348: 4328: 4295: 4272: 4252: 4229: 4162: 4146: 4110: 3980: 3930: 3903: 3888: 3859: 3819: 3799: 3771: 3751: 3710: 3687: 3667: 3636: 3616: 3585: 3560:line with two origins 3553: 3530: 3513:line with two origins 3500: 3472: 3452: 3428: 3365: 3333: 3304: 3275: 3245: 3213: 3211:{\displaystyle L^{*}} 3180: 3157: 3127: 3107: 3087: 3067: 3047: 3023: 2999: 2971: 2936: 2901: 2881: 2846: 2826: 2803: 2783: 2745: 2711: 2691: 2659: 2637: 2610: 2580: 2540: 2520: 2500: 2447: 2423: 2367: 2345: 2308: 2279: 2253: 2224: 2195: 2159: 2131: 2085: 2049: 2004: 1951: 1949:{\displaystyle (1,2]} 1924: 1922:{\displaystyle [0,1)} 1890: 1855: 1820: 1818:{\displaystyle [0,1)} 1781: 1779:{\displaystyle [0,2)} 1732: 1710: 1690: 1670: 1650: 1630: 1610: 1590: 1567: 1547: 1527: 1499: 1461: 1441: 1398: 1371: 1347: 1317: 1294: 1274: 1244: 1192: 1167: 1165:{\displaystyle (A,B)} 1135: 1080: 1028: 979: 922: 898: 874: 847: 824: 804: 784: 761: 741: 721: 698: 678: 655: 619: 591: 559: 527: 496: 474: 450: 427: 403: 380: 357: 322: 294: 255: 223: 191: 6337:Invariance of domain 6289:Euler characteristic 6263:Bundle (mathematics) 5654: 5634: 5577: 5557: 5463:{\displaystyle f(X)} 5445: 5425: 5393: 5373: 5353: 5312: 5292: 5272: 5089: 5085:. Now we know that: 5062: 5035: 5008: 4988: 4929: 4896: 4869: 4836: 4816: 4789: 4762: 4736: 4710: 4658: 4614: 4584: 4539: 4472: 4408: 4365: 4337: 4304: 4284: 4261: 4241: 4182: 4126: 3996: 3939: 3917: 3895:topological manifold 3868: 3839: 3808: 3788: 3760: 3740: 3699: 3676: 3648: 3625: 3597: 3574: 3542: 3519: 3515:; its two copies of 3489: 3461: 3441: 3393: 3354: 3313: 3284: 3262: 3232: 3195: 3169: 3144: 3116: 3096: 3076: 3056: 3036: 3030:equivalence relation 3012: 2988: 2945: 2910: 2890: 2858: 2835: 2815: 2792: 2772: 2758:path-connected space 2700: 2671: 2648: 2626: 2599: 2549: 2529: 2509: 2469: 2464:general linear group 2452:is itself connected. 2436: 2412: 2381:totally disconnected 2354: 2332: 2288: 2262: 2233: 2204: 2182: 2146: 2105: 2065: 2014: 1960: 1928: 1901: 1864: 1829: 1797: 1758: 1754:The closed interval 1719: 1699: 1679: 1659: 1639: 1619: 1599: 1579: 1556: 1536: 1516: 1488: 1479:totally disconnected 1450: 1407: 1384: 1360: 1326: 1303: 1283: 1256: 1201: 1176: 1144: 1089: 1037: 988: 948: 911: 887: 881:connected components 863: 833: 813: 793: 770: 750: 730: 710: 687: 664: 644: 636:Connected components 608: 568: 564:are constant, where 536: 516: 485: 463: 439: 435:The only subsets of 416: 392: 388:The only subsets of 369: 346: 311: 283: 244: 212: 180: 6347:Tychonoff's theorem 6342:PoincarĂ© conjecture 6096:General (point-set) 6017:"Connective Spaces" 5736:Connectedness locus 5674:are also connected. 4606:is a separation of 4576:is connected, then 3720:Local connectedness 2430:homotopy equivalent 1470:Disconnected spaces 1435: 1341: 1172:is a separation of 6332:De Rham cohomology 6253:Polyhedral complex 6243:Simplicial complex 5980:Weisstein, Eric W. 5773:Pixel connectivity 5719:Mathematics portal 5695:deleted comb space 5687:contractible space 5660: 5640: 5624:topological spaces 5589: 5563: 5460: 5431: 5411: 5379: 5359: 5338: 5318: 5298: 5278: 5258: 5075: 5048: 5021: 4994: 4974: 4915: 4890: 4875: 4855: 4822: 4802: 4775: 4748: 4722: 4688: 4644: 4596: 4566: 4519: 4455: 4387: 4343: 4323: 4290: 4267: 4247: 4224: 4165: 4141: 4117:Euclidean topology 4105: 4065: 3975: 3925: 3906: 3883: 3854: 3814: 3794: 3766: 3746: 3705: 3682: 3662: 3631: 3611: 3580: 3548: 3525: 3495: 3467: 3447: 3423: 3360: 3328: 3299: 3270: 3240: 3208: 3175: 3152: 3138:pathwise connected 3122: 3102: 3082: 3062: 3042: 3018: 2994: 2966: 2931: 2896: 2876: 2841: 2821: 2798: 2778: 2752: 2738:Path connectedness 2706: 2686: 2654: 2642:has constant rank. 2632: 2605: 2575: 2535: 2515: 2495: 2442: 2418: 2362: 2340: 2303: 2274: 2248: 2219: 2190: 2154: 2126: 2080: 2044: 1999: 1946: 1919: 1885: 1850: 1815: 1776: 1727: 1705: 1685: 1665: 1645: 1625: 1605: 1585: 1562: 1542: 1522: 1494: 1456: 1436: 1423: 1396:{\displaystyle x.} 1393: 1366: 1342: 1329: 1315:{\displaystyle X,} 1312: 1289: 1269: 1239: 1187: 1162: 1130: 1075: 1023: 974: 917: 893: 869: 845:{\displaystyle x.} 842: 819: 799: 782:{\displaystyle x;} 779: 756: 736: 716: 693: 676:{\displaystyle X,} 673: 650: 614: 586: 554: 522: 491: 479:and the empty set. 469: 445: 432:and the empty set. 422: 398: 375: 352: 317: 289: 250: 218: 186: 6447: 6446: 6236:fundamental group 5999:"Connected space" 5963:. Prentice Hall. 5957:Munkres, James R. 5867:George F. Simmons 5663:{\displaystyle X} 5643:{\displaystyle X} 5626:, for instance: 5566:{\displaystyle n} 5434:{\displaystyle X} 5382:{\displaystyle Y} 5362:{\displaystyle X} 5321:{\displaystyle X} 5301:{\displaystyle X} 5281:{\displaystyle X} 4997:{\displaystyle Y} 4888: 4878:{\displaystyle i} 4825:{\displaystyle Y} 4346:{\displaystyle X} 4293:{\displaystyle X} 4270:{\displaystyle V} 4250:{\displaystyle U} 4064: 3817:{\displaystyle X} 3797:{\displaystyle X} 3778:locally connected 3769:{\displaystyle x} 3749:{\displaystyle x} 3733:locally connected 3708:{\displaystyle X} 3685:{\displaystyle X} 3634:{\displaystyle X} 3583:{\displaystyle X} 3551:{\displaystyle X} 3528:{\displaystyle 0} 3470:{\displaystyle X} 3450:{\displaystyle X} 3376:arcwise connected 3363:{\displaystyle X} 3346:Arc connectedness 3178:{\displaystyle X} 3125:{\displaystyle X} 3105:{\displaystyle y} 3085:{\displaystyle x} 3065:{\displaystyle y} 3045:{\displaystyle x} 3021:{\displaystyle X} 3006:equivalence class 2997:{\displaystyle X} 2899:{\displaystyle X} 2844:{\displaystyle f} 2824:{\displaystyle X} 2810:topological space 2801:{\displaystyle y} 2781:{\displaystyle x} 2746:This subspace of 2732:subspace topology 2709:{\displaystyle R} 2657:{\displaystyle R} 2635:{\displaystyle R} 2608:{\displaystyle R} 2538:{\displaystyle n} 2518:{\displaystyle n} 2445:{\displaystyle X} 2421:{\displaystyle X} 2002:{\displaystyle .} 1791:subspace topology 1739:quotient topology 1708:{\displaystyle V} 1688:{\displaystyle U} 1668:{\displaystyle X} 1648:{\displaystyle y} 1628:{\displaystyle V} 1608:{\displaystyle x} 1588:{\displaystyle U} 1565:{\displaystyle X} 1545:{\displaystyle y} 1525:{\displaystyle x} 1508:totally separated 1497:{\displaystyle X} 1459:{\displaystyle X} 1369:{\displaystyle x} 1292:{\displaystyle x} 920:{\displaystyle X} 896:{\displaystyle X} 822:{\displaystyle X} 759:{\displaystyle X} 739:{\displaystyle X} 719:{\displaystyle x} 696:{\displaystyle x} 653:{\displaystyle x} 640:Given some point 617:{\displaystyle X} 598:discrete topology 525:{\displaystyle X} 494:{\displaystyle X} 472:{\displaystyle X} 448:{\displaystyle X} 425:{\displaystyle X} 401:{\displaystyle X} 378:{\displaystyle X} 355:{\displaystyle X} 320:{\displaystyle X} 292:{\displaystyle X} 278:topological space 272:Formal definition 265:locally connected 253:{\displaystyle n} 221:{\displaystyle X} 189:{\displaystyle X} 153:topological space 64:and orange space 16:(Redirected from 6472: 6460:General topology 6437: 6436: 6410: 6409: 6400: 6390: 6380: 6379: 6368: 6367: 6162: 6075: 6068: 6061: 6052: 6045: 6043: 6042: 6036: 6021: 6011: 5993: 5992: 5974: 5942: 5941: 5927: 5921: 5920: 5906: 5900: 5891: 5885: 5884: 5863: 5857: 5856: 5843:General Topology 5838: 5832: 5831: 5824: 5818: 5817: 5789: 5732: 5721: 5716: 5715: 5669: 5667: 5666: 5661: 5649: 5647: 5646: 5641: 5598: 5596: 5595: 5590: 5572: 5570: 5569: 5564: 5469: 5467: 5466: 5461: 5440: 5438: 5437: 5432: 5420: 5418: 5417: 5412: 5388: 5386: 5385: 5380: 5368: 5366: 5365: 5360: 5327: 5325: 5324: 5319: 5307: 5305: 5304: 5299: 5287: 5285: 5284: 5279: 5267: 5265: 5264: 5259: 5257: 5253: 5252: 5251: 5239: 5238: 5221: 5217: 5216: 5215: 5203: 5202: 5185: 5184: 5172: 5168: 5167: 5166: 5154: 5153: 5136: 5135: 5123: 5119: 5118: 5117: 5084: 5082: 5081: 5076: 5074: 5073: 5058:is contained in 5057: 5055: 5054: 5049: 5047: 5046: 5030: 5028: 5027: 5022: 5020: 5019: 5003: 5001: 5000: 4995: 4983: 4981: 4980: 4975: 4973: 4972: 4960: 4959: 4947: 4946: 4924: 4922: 4921: 4916: 4914: 4913: 4884: 4882: 4881: 4876: 4864: 4862: 4861: 4856: 4854: 4853: 4831: 4829: 4828: 4823: 4811: 4809: 4808: 4803: 4801: 4800: 4784: 4782: 4781: 4776: 4774: 4773: 4757: 4755: 4754: 4749: 4731: 4729: 4728: 4723: 4697: 4695: 4694: 4689: 4653: 4651: 4650: 4645: 4609: 4605: 4603: 4602: 4597: 4579: 4575: 4573: 4572: 4567: 4562: 4561: 4549: 4528: 4526: 4525: 4520: 4512: 4511: 4493: 4492: 4464: 4462: 4461: 4456: 4448: 4447: 4435: 4434: 4396: 4394: 4393: 4388: 4380: 4379: 4352: 4350: 4349: 4344: 4332: 4330: 4329: 4324: 4319: 4318: 4299: 4297: 4296: 4291: 4276: 4274: 4273: 4268: 4256: 4254: 4253: 4248: 4233: 4231: 4230: 4225: 4150: 4148: 4147: 4142: 4140: 4139: 4134: 4122:by inclusion in 4114: 4112: 4111: 4106: 4104: 4100: 4075: 4071: 4070: 4066: 4057: 3984: 3982: 3981: 3976: 3934: 3932: 3931: 3926: 3924: 3892: 3890: 3889: 3884: 3882: 3881: 3876: 3863: 3861: 3860: 3855: 3853: 3852: 3847: 3833: 3832: 3823: 3821: 3820: 3815: 3803: 3801: 3800: 3795: 3775: 3773: 3772: 3767: 3755: 3753: 3752: 3747: 3714: 3712: 3711: 3706: 3691: 3689: 3688: 3683: 3671: 3669: 3668: 3663: 3661: 3640: 3638: 3637: 3632: 3620: 3618: 3617: 3612: 3610: 3589: 3587: 3586: 3581: 3557: 3555: 3554: 3549: 3534: 3532: 3531: 3526: 3505:-Hausdorff space 3504: 3502: 3501: 3496: 3476: 3474: 3473: 3468: 3456: 3454: 3453: 3448: 3432: 3430: 3429: 3424: 3369: 3367: 3366: 3361: 3337: 3335: 3334: 3329: 3327: 3326: 3321: 3308: 3306: 3305: 3300: 3298: 3297: 3292: 3279: 3277: 3276: 3271: 3269: 3249: 3247: 3246: 3241: 3239: 3217: 3215: 3214: 3209: 3207: 3206: 3184: 3182: 3181: 3176: 3161: 3159: 3158: 3153: 3151: 3131: 3129: 3128: 3123: 3111: 3109: 3108: 3103: 3091: 3089: 3088: 3083: 3071: 3069: 3068: 3063: 3051: 3049: 3048: 3043: 3027: 3025: 3024: 3019: 3003: 3001: 3000: 2995: 2982: 2981: 2975: 2973: 2972: 2967: 2940: 2938: 2937: 2932: 2905: 2903: 2902: 2897: 2885: 2883: 2882: 2879:{\displaystyle } 2877: 2850: 2848: 2847: 2842: 2830: 2828: 2827: 2822: 2807: 2805: 2804: 2799: 2787: 2785: 2784: 2779: 2760: 2759: 2715: 2713: 2712: 2707: 2695: 2693: 2692: 2687: 2663: 2661: 2660: 2655: 2641: 2639: 2638: 2633: 2614: 2612: 2611: 2606: 2584: 2582: 2581: 2576: 2571: 2544: 2542: 2541: 2536: 2524: 2522: 2521: 2516: 2504: 2502: 2501: 2496: 2491: 2451: 2449: 2448: 2443: 2427: 2425: 2424: 2419: 2396:SierpiĹ„ski space 2371: 2369: 2368: 2363: 2361: 2349: 2347: 2346: 2341: 2339: 2312: 2310: 2309: 2304: 2302: 2301: 2296: 2283: 2281: 2280: 2275: 2257: 2255: 2254: 2249: 2228: 2226: 2225: 2220: 2218: 2217: 2212: 2199: 2197: 2196: 2191: 2189: 2175:is disconnected. 2163: 2161: 2160: 2155: 2153: 2135: 2133: 2132: 2127: 2092:simply connected 2089: 2087: 2086: 2081: 2079: 2078: 2073: 2054:is disconnected. 2053: 2051: 2050: 2045: 2008: 2006: 2005: 2000: 1955: 1953: 1952: 1947: 1926: 1925: 1920: 1894: 1892: 1891: 1886: 1859: 1857: 1856: 1851: 1824: 1822: 1821: 1816: 1785: 1783: 1782: 1777: 1736: 1734: 1733: 1728: 1726: 1714: 1712: 1711: 1706: 1694: 1692: 1691: 1686: 1675:is the union of 1674: 1672: 1671: 1666: 1654: 1652: 1651: 1646: 1634: 1632: 1631: 1626: 1614: 1612: 1611: 1606: 1594: 1592: 1591: 1586: 1571: 1569: 1568: 1563: 1551: 1549: 1548: 1543: 1531: 1529: 1528: 1523: 1510: 1509: 1503: 1501: 1500: 1495: 1481: 1480: 1465: 1463: 1462: 1457: 1445: 1443: 1442: 1437: 1431: 1419: 1418: 1402: 1400: 1399: 1394: 1375: 1373: 1372: 1367: 1356:sets containing 1351: 1349: 1348: 1343: 1337: 1321: 1319: 1318: 1313: 1298: 1296: 1295: 1290: 1278: 1276: 1275: 1270: 1268: 1267: 1248: 1246: 1245: 1240: 1232: 1231: 1213: 1212: 1196: 1194: 1193: 1188: 1183: 1171: 1169: 1168: 1163: 1139: 1137: 1136: 1131: 1111: 1084: 1082: 1081: 1076: 1059: 1032: 1030: 1029: 1024: 1019: 1018: 1000: 999: 983: 981: 980: 975: 973: 972: 960: 959: 938:rational numbers 926: 924: 923: 918: 902: 900: 899: 894: 878: 876: 875: 870: 851: 849: 848: 843: 828: 826: 825: 820: 808: 806: 805: 800: 788: 786: 785: 780: 765: 763: 762: 757: 745: 743: 742: 737: 725: 723: 722: 717: 702: 700: 699: 694: 682: 680: 679: 674: 659: 657: 656: 651: 623: 621: 620: 615: 595: 593: 592: 587: 563: 561: 560: 555: 531: 529: 528: 523: 500: 498: 497: 492: 478: 476: 475: 470: 454: 452: 451: 446: 431: 429: 428: 423: 407: 405: 404: 399: 384: 382: 381: 376: 361: 359: 358: 353: 326: 324: 323: 318: 305: 304: 298: 296: 295: 290: 259: 257: 256: 251: 237:simply connected 227: 225: 224: 219: 202: 201: 195: 193: 192: 187: 128:has genus 1 and 110:simply connected 70:connected spaces 49: 21: 6480: 6479: 6475: 6474: 6473: 6471: 6470: 6469: 6450: 6449: 6448: 6443: 6374: 6356: 6352:Urysohn's lemma 6313: 6277: 6163: 6154: 6126:low-dimensional 6084: 6079: 6049: 6040: 6038: 6034: 6019: 6014: 5996: 5983:"Connected Set" 5978: 5977: 5971: 5955: 5951: 5949:Further reading 5946: 5945: 5929: 5928: 5924: 5908: 5907: 5903: 5892: 5888: 5881: 5865: 5864: 5860: 5853: 5840: 5839: 5835: 5826: 5825: 5821: 5806:10.2307/2321676 5791: 5790: 5786: 5781: 5730: 5717: 5710: 5707: 5652: 5651: 5632: 5631: 5620: 5575: 5574: 5555: 5554: 5553:graph (and any 5543: 5443: 5442: 5423: 5422: 5391: 5390: 5371: 5370: 5351: 5350: 5343: 5330: 5310: 5309: 5290: 5289: 5270: 5269: 5243: 5230: 5229: 5225: 5207: 5194: 5193: 5189: 5176: 5158: 5145: 5144: 5140: 5127: 5109: 5102: 5098: 5087: 5086: 5065: 5060: 5059: 5038: 5033: 5032: 5011: 5006: 5005: 4986: 4985: 4964: 4951: 4938: 4927: 4926: 4905: 4894: 4893: 4867: 4866: 4845: 4834: 4833: 4814: 4813: 4792: 4787: 4786: 4765: 4760: 4759: 4734: 4733: 4708: 4707: 4656: 4655: 4612: 4611: 4607: 4582: 4581: 4577: 4553: 4537: 4536: 4497: 4484: 4470: 4469: 4439: 4426: 4406: 4405: 4399:disjoint unions 4371: 4363: 4362: 4335: 4334: 4310: 4302: 4301: 4282: 4281: 4259: 4258: 4239: 4238: 4180: 4179: 4157: 4129: 4124: 4123: 4051: 4038: 4034: 4033: 4029: 3994: 3993: 3937: 3936: 3915: 3914: 3871: 3866: 3865: 3842: 3837: 3836: 3830: 3829: 3806: 3805: 3786: 3785: 3758: 3757: 3738: 3737: 3728: 3722: 3697: 3696: 3674: 3673: 3646: 3645: 3623: 3622: 3595: 3594: 3572: 3571: 3540: 3539: 3517: 3516: 3487: 3486: 3482:Hausdorff space 3459: 3458: 3439: 3438: 3391: 3390: 3352: 3351: 3348: 3316: 3311: 3310: 3287: 3282: 3281: 3260: 3259: 3230: 3229: 3225:Subsets of the 3198: 3193: 3192: 3167: 3166: 3142: 3141: 3114: 3113: 3094: 3093: 3074: 3073: 3054: 3053: 3034: 3033: 3010: 3009: 2986: 2985: 2979: 2978: 2943: 2942: 2908: 2907: 2888: 2887: 2856: 2855: 2833: 2832: 2813: 2812: 2790: 2789: 2770: 2769: 2757: 2756: 2740: 2698: 2697: 2669: 2668: 2646: 2645: 2624: 2623: 2597: 2596: 2547: 2546: 2527: 2526: 2507: 2506: 2467: 2466: 2434: 2433: 2410: 2409: 2352: 2351: 2330: 2329: 2291: 2286: 2285: 2260: 2259: 2231: 2230: 2207: 2202: 2201: 2180: 2179: 2173:Sorgenfrey line 2164:, the space of 2144: 2143: 2103: 2102: 2099:Euclidean plane 2068: 2063: 2062: 2012: 2011: 1958: 1957: 1899: 1898: 1862: 1861: 1827: 1826: 1795: 1794: 1756: 1755: 1751: 1717: 1716: 1697: 1696: 1677: 1676: 1657: 1656: 1637: 1636: 1617: 1616: 1597: 1596: 1577: 1576: 1554: 1553: 1534: 1533: 1514: 1513: 1507: 1506: 1486: 1485: 1478: 1477: 1472: 1448: 1447: 1410: 1405: 1404: 1382: 1381: 1378:quasi-component 1358: 1357: 1324: 1323: 1301: 1300: 1281: 1280: 1259: 1254: 1253: 1223: 1204: 1199: 1198: 1174: 1173: 1142: 1141: 1087: 1086: 1035: 1034: 1010: 991: 986: 985: 964: 951: 946: 945: 909: 908: 885: 884: 861: 860: 831: 830: 811: 810: 791: 790: 768: 767: 748: 747: 728: 727: 708: 707: 685: 684: 662: 661: 642: 641: 638: 630:Felix Hausdorff 606: 605: 566: 565: 534: 533: 514: 513: 512:functions from 483: 482: 461: 460: 437: 436: 414: 413: 390: 389: 367: 366: 344: 343: 309: 308: 302: 301: 281: 280: 274: 242: 241: 210: 209: 199: 198: 178: 177: 159:of two or more 149:connected space 137: 136: 135: 134: 133: 100:. Furthermore, 95: 91: 87: 83: 60:, yellow space 50: 41: 40: 28: 23: 22: 15: 12: 11: 5: 6478: 6476: 6468: 6467: 6462: 6452: 6451: 6445: 6444: 6442: 6441: 6431: 6430: 6429: 6424: 6419: 6404: 6394: 6384: 6372: 6361: 6358: 6357: 6355: 6354: 6349: 6344: 6339: 6334: 6329: 6323: 6321: 6315: 6314: 6312: 6311: 6306: 6301: 6299:Winding number 6296: 6291: 6285: 6283: 6279: 6278: 6276: 6275: 6270: 6265: 6260: 6255: 6250: 6245: 6240: 6239: 6238: 6233: 6231:homotopy group 6223: 6222: 6221: 6216: 6211: 6206: 6201: 6191: 6186: 6181: 6171: 6169: 6165: 6164: 6157: 6155: 6153: 6152: 6147: 6142: 6141: 6140: 6130: 6129: 6128: 6118: 6113: 6108: 6103: 6098: 6092: 6090: 6086: 6085: 6080: 6078: 6077: 6070: 6063: 6055: 6048: 6047: 6012: 5994: 5975: 5969: 5952: 5950: 5947: 5944: 5943: 5937:Stack Exchange 5922: 5916:Stack Exchange 5901: 5894:Charles Weibel 5886: 5879: 5858: 5851: 5833: 5819: 5800:(9): 720–726. 5783: 5782: 5780: 5777: 5776: 5775: 5770: 5764: 5756: 5750: 5744: 5738: 5733: 5723: 5722: 5706: 5703: 5691: 5690: 5683: 5675: 5659: 5639: 5619: 5616: 5588: 5585: 5582: 5562: 5542: 5539: 5538: 5537: 5534: 5531: 5524: 5521: 5514: 5507: 5504: 5501: 5494: 5487: 5484: 5481: 5478: 5475: 5459: 5456: 5453: 5450: 5430: 5410: 5407: 5404: 5401: 5398: 5378: 5358: 5342: 5339: 5328:is connected. 5317: 5297: 5277: 5256: 5250: 5246: 5242: 5237: 5233: 5228: 5224: 5220: 5214: 5210: 5206: 5201: 5197: 5192: 5188: 5183: 5179: 5175: 5171: 5165: 5161: 5157: 5152: 5148: 5143: 5139: 5134: 5130: 5126: 5122: 5116: 5112: 5108: 5105: 5101: 5097: 5094: 5072: 5068: 5045: 5041: 5018: 5014: 4993: 4971: 4967: 4963: 4958: 4954: 4950: 4945: 4941: 4937: 4934: 4912: 4908: 4904: 4901: 4887: 4874: 4852: 4848: 4844: 4841: 4821: 4799: 4795: 4772: 4768: 4747: 4744: 4741: 4721: 4718: 4715: 4704:set difference 4700: 4699: 4687: 4684: 4681: 4678: 4675: 4672: 4669: 4666: 4663: 4643: 4640: 4637: 4634: 4631: 4628: 4625: 4622: 4619: 4595: 4592: 4589: 4565: 4560: 4556: 4552: 4548: 4544: 4534:quotient space 4530: 4518: 4515: 4510: 4507: 4504: 4500: 4496: 4491: 4487: 4483: 4480: 4477: 4466: 4454: 4451: 4446: 4442: 4438: 4433: 4429: 4425: 4422: 4419: 4416: 4413: 4402: 4386: 4383: 4378: 4374: 4370: 4356: 4342: 4322: 4317: 4313: 4309: 4289: 4266: 4246: 4223: 4220: 4217: 4214: 4211: 4208: 4205: 4202: 4199: 4196: 4193: 4190: 4187: 4156: 4155:Set operations 4153: 4138: 4133: 4103: 4099: 4096: 4093: 4090: 4087: 4084: 4081: 4078: 4074: 4069: 4063: 4060: 4054: 4050: 4047: 4044: 4041: 4037: 4032: 4028: 4025: 4022: 4019: 4016: 4013: 4010: 4007: 4004: 4001: 3974: 3971: 3968: 3965: 3962: 3959: 3956: 3953: 3950: 3947: 3944: 3923: 3880: 3875: 3851: 3846: 3813: 3793: 3765: 3745: 3724:Main article: 3721: 3718: 3717: 3716: 3704: 3693: 3681: 3660: 3656: 3653: 3642: 3630: 3609: 3605: 3602: 3591: 3579: 3568: 3547: 3524: 3494: 3466: 3446: 3422: 3419: 3416: 3413: 3410: 3407: 3404: 3401: 3398: 3386:, which is an 3370:is said to be 3359: 3347: 3344: 3325: 3320: 3296: 3291: 3268: 3252:if and only if 3250:are connected 3238: 3205: 3201: 3174: 3150: 3134:path-connected 3132:is said to be 3121: 3101: 3081: 3061: 3052:equivalent to 3041: 3017: 2993: 2980:path-component 2965: 2962: 2959: 2956: 2953: 2950: 2930: 2927: 2924: 2921: 2918: 2915: 2895: 2875: 2872: 2869: 2866: 2863: 2840: 2820: 2797: 2777: 2739: 2736: 2720: 2719: 2718: 2717: 2705: 2685: 2682: 2679: 2676: 2653: 2643: 2631: 2616: 2604: 2586: 2574: 2570: 2566: 2563: 2560: 2557: 2554: 2534: 2514: 2494: 2490: 2486: 2483: 2480: 2477: 2474: 2460: 2453: 2441: 2417: 2406: 2399: 2388: 2373: 2360: 2338: 2314: 2300: 2295: 2273: 2270: 2267: 2247: 2244: 2241: 2238: 2216: 2211: 2188: 2176: 2169: 2152: 2141: 2138: 2125: 2122: 2119: 2116: 2113: 2110: 2095: 2077: 2072: 2055: 2043: 2040: 2037: 2034: 2031: 2028: 2025: 2022: 2019: 2009: 1998: 1995: 1992: 1989: 1986: 1983: 1980: 1977: 1974: 1971: 1968: 1965: 1945: 1942: 1939: 1936: 1933: 1918: 1915: 1912: 1909: 1906: 1895: 1884: 1881: 1878: 1875: 1872: 1869: 1849: 1846: 1843: 1840: 1837: 1834: 1814: 1811: 1808: 1805: 1802: 1775: 1772: 1769: 1766: 1763: 1750: 1747: 1725: 1704: 1684: 1664: 1644: 1624: 1604: 1584: 1561: 1541: 1521: 1493: 1471: 1468: 1455: 1434: 1430: 1426: 1422: 1417: 1413: 1392: 1389: 1365: 1340: 1336: 1332: 1311: 1308: 1288: 1266: 1262: 1238: 1235: 1230: 1226: 1222: 1219: 1216: 1211: 1207: 1186: 1182: 1161: 1158: 1155: 1152: 1149: 1129: 1126: 1123: 1120: 1117: 1114: 1110: 1106: 1103: 1100: 1097: 1094: 1074: 1071: 1068: 1065: 1062: 1058: 1054: 1051: 1048: 1045: 1042: 1022: 1017: 1013: 1009: 1006: 1003: 998: 994: 971: 967: 963: 958: 954: 916: 892: 868: 841: 838: 829:that contains 818: 798: 778: 775: 755: 735: 715: 692: 672: 669: 649: 637: 634: 613: 602: 601: 585: 582: 579: 576: 573: 553: 550: 547: 544: 541: 521: 506: 503:separated sets 490: 480: 468: 444: 433: 421: 397: 386: 374: 351: 327:is said to be 316: 299:is said to be 288: 273: 270: 249: 233:path connected 217: 185: 93: 89: 85: 81: 51: 44: 43: 42: 34: 33: 32: 31: 26: 24: 18:Path-connected 14: 13: 10: 9: 6: 4: 3: 2: 6477: 6466: 6463: 6461: 6458: 6457: 6455: 6440: 6432: 6428: 6425: 6423: 6420: 6418: 6415: 6414: 6413: 6405: 6403: 6399: 6395: 6393: 6389: 6385: 6383: 6378: 6373: 6371: 6363: 6362: 6359: 6353: 6350: 6348: 6345: 6343: 6340: 6338: 6335: 6333: 6330: 6328: 6325: 6324: 6322: 6320: 6316: 6310: 6309:Orientability 6307: 6305: 6302: 6300: 6297: 6295: 6292: 6290: 6287: 6286: 6284: 6280: 6274: 6271: 6269: 6266: 6264: 6261: 6259: 6256: 6254: 6251: 6249: 6246: 6244: 6241: 6237: 6234: 6232: 6229: 6228: 6227: 6224: 6220: 6217: 6215: 6212: 6210: 6207: 6205: 6202: 6200: 6197: 6196: 6195: 6192: 6190: 6187: 6185: 6182: 6180: 6176: 6173: 6172: 6170: 6166: 6161: 6151: 6148: 6146: 6145:Set-theoretic 6143: 6139: 6136: 6135: 6134: 6131: 6127: 6124: 6123: 6122: 6119: 6117: 6114: 6112: 6109: 6107: 6106:Combinatorial 6104: 6102: 6099: 6097: 6094: 6093: 6091: 6087: 6083: 6076: 6071: 6069: 6064: 6062: 6057: 6056: 6053: 6037:on 2016-03-04 6033: 6029: 6025: 6018: 6013: 6010: 6006: 6005: 6000: 5995: 5990: 5989: 5984: 5981: 5976: 5972: 5970:0-13-181629-2 5966: 5962: 5958: 5954: 5953: 5948: 5939: 5938: 5933: 5926: 5923: 5918: 5917: 5912: 5905: 5902: 5899: 5895: 5890: 5887: 5882: 5880:0-89874-551-9 5876: 5872: 5868: 5862: 5859: 5854: 5852:0-486-43479-6 5848: 5844: 5837: 5834: 5829: 5823: 5820: 5815: 5811: 5807: 5803: 5799: 5795: 5788: 5785: 5778: 5774: 5771: 5768: 5765: 5763: 5761: 5757: 5754: 5751: 5748: 5745: 5742: 5739: 5737: 5734: 5728: 5725: 5724: 5720: 5714: 5709: 5704: 5702: 5700: 5696: 5688: 5684: 5680: 5676: 5673: 5657: 5637: 5629: 5628: 5627: 5625: 5617: 5615: 5613: 5608: 5606: 5600: 5586: 5583: 5580: 5560: 5552: 5547: 5540: 5535: 5532: 5529: 5525: 5522: 5519: 5515: 5512: 5508: 5505: 5502: 5499: 5495: 5492: 5488: 5485: 5482: 5479: 5476: 5473: 5454: 5448: 5428: 5408: 5402: 5399: 5396: 5376: 5356: 5348: 5345: 5344: 5340: 5334: 5329: 5315: 5295: 5275: 5254: 5248: 5244: 5240: 5235: 5231: 5226: 5222: 5218: 5212: 5208: 5204: 5199: 5195: 5190: 5186: 5181: 5177: 5173: 5169: 5163: 5159: 5155: 5150: 5146: 5141: 5137: 5132: 5128: 5124: 5120: 5114: 5110: 5106: 5103: 5099: 5095: 5092: 5070: 5066: 5043: 5039: 5016: 5012: 4991: 4969: 4965: 4961: 4956: 4952: 4948: 4943: 4939: 4935: 4932: 4910: 4906: 4902: 4899: 4886: 4872: 4850: 4846: 4842: 4839: 4819: 4797: 4793: 4770: 4766: 4745: 4739: 4719: 4716: 4713: 4705: 4682: 4676: 4673: 4667: 4661: 4638: 4632: 4629: 4623: 4617: 4593: 4590: 4587: 4558: 4554: 4546: 4542: 4535: 4531: 4513: 4508: 4505: 4502: 4498: 4494: 4489: 4485: 4481: 4478: 4467: 4449: 4444: 4440: 4436: 4431: 4427: 4423: 4420: 4417: 4414: 4403: 4400: 4381: 4376: 4372: 4368: 4360: 4359: 4358: 4354: 4340: 4315: 4311: 4287: 4278: 4264: 4244: 4235: 4218: 4215: 4212: 4206: 4200: 4197: 4194: 4188: 4185: 4177: 4172: 4170: 4161: 4154: 4152: 4136: 4121: 4118: 4101: 4094: 4091: 4088: 4082: 4079: 4076: 4072: 4067: 4061: 4058: 4052: 4048: 4045: 4042: 4039: 4035: 4030: 4026: 4017: 4014: 4011: 4002: 3999: 3992:, defined as 3991: 3986: 3969: 3966: 3963: 3957: 3951: 3948: 3945: 3913:intervals in 3912: 3902: 3898: 3896: 3878: 3849: 3834: 3825: 3811: 3791: 3783: 3779: 3763: 3743: 3736: 3734: 3727: 3719: 3702: 3694: 3679: 3654: 3651: 3643: 3628: 3603: 3600: 3592: 3577: 3569: 3565: 3564: 3563: 3561: 3545: 3536: 3522: 3514: 3510: 3506: 3483: 3478: 3464: 3444: 3436: 3435:arc-component 3420: 3411: 3408: 3405: 3399: 3396: 3389: 3385: 3381: 3377: 3373: 3372:arc-connected 3357: 3345: 3343: 3341: 3323: 3294: 3257: 3253: 3228: 3223: 3221: 3203: 3199: 3191: 3186: 3172: 3164: 3139: 3135: 3119: 3099: 3079: 3059: 3039: 3031: 3015: 3007: 2991: 2983: 2963: 2960: 2954: 2948: 2928: 2925: 2919: 2913: 2893: 2870: 2867: 2864: 2854: 2853:unit interval 2838: 2818: 2811: 2795: 2775: 2768:from a point 2767: 2766: 2761: 2749: 2744: 2737: 2735: 2733: 2729: 2725: 2703: 2683: 2680: 2677: 2674: 2667: 2651: 2644: 2629: 2621: 2617: 2602: 2594: 2593: 2591: 2587: 2564: 2561: 2555: 2552: 2532: 2512: 2484: 2481: 2475: 2472: 2465: 2461: 2458: 2454: 2439: 2431: 2415: 2407: 2404: 2400: 2397: 2393: 2389: 2386: 2382: 2378: 2374: 2327: 2323: 2322:Hilbert space 2319: 2315: 2298: 2271: 2268: 2265: 2245: 2242: 2239: 2236: 2214: 2177: 2174: 2170: 2167: 2142: 2139: 2123: 2117: 2114: 2111: 2100: 2096: 2093: 2075: 2060: 2059:convex subset 2056: 2038: 2032: 2026: 2023: 2020: 2010: 1996: 1990: 1987: 1984: 1978: 1972: 1969: 1966: 1940: 1937: 1934: 1913: 1910: 1907: 1897:The union of 1896: 1882: 1876: 1873: 1870: 1847: 1841: 1838: 1835: 1809: 1806: 1803: 1792: 1789: 1770: 1767: 1764: 1753: 1752: 1748: 1746: 1744: 1740: 1702: 1682: 1662: 1642: 1622: 1602: 1582: 1575: 1559: 1539: 1519: 1511: 1491: 1483: 1482: 1469: 1467: 1453: 1432: 1428: 1420: 1415: 1390: 1387: 1379: 1363: 1355: 1338: 1334: 1309: 1306: 1286: 1264: 1250: 1236: 1233: 1228: 1224: 1220: 1217: 1214: 1209: 1205: 1184: 1156: 1153: 1150: 1127: 1121: 1118: 1115: 1112: 1104: 1101: 1095: 1092: 1069: 1066: 1063: 1060: 1052: 1049: 1043: 1040: 1033:and then set 1020: 1015: 1011: 1007: 1004: 1001: 996: 992: 969: 965: 961: 956: 952: 943: 939: 934: 933:closed subset 930: 914: 906: 890: 882: 866: 859: 855: 839: 836: 816: 796: 776: 773: 766:that contain 753: 733: 713: 706: 690: 670: 667: 647: 635: 633: 631: 627: 626:Frigyes Riesz 611: 599: 580: 577: 574: 548: 545: 542: 519: 511: 507: 504: 488: 481: 466: 458: 442: 434: 419: 411: 395: 387: 372: 365: 364: 363: 349: 340: 338: 334: 330: 314: 306: 286: 279: 271: 269: 267: 266: 261: 247: 238: 234: 229: 215: 207: 203: 200:connected set 183: 174: 172: 168: 165: 162: 158: 154: 150: 146: 142: 131: 127: 123: 119: 115: 111: 107: 103: 99: 79: 75: 71: 67: 63: 59: 56:, pink space 55: 48: 38: 30: 19: 6439:Publications 6304:Chern number 6294:Betti number 6203: 6177: / 6168:Key concepts 6116:Differential 6039:. Retrieved 6032:the original 6027: 6023: 6002: 5986: 5960: 5935: 5925: 5914: 5904: 5889: 5870: 5861: 5842: 5836: 5822: 5797: 5793: 5787: 5759: 5692: 5621: 5609: 5601: 5573:-cycle with 5544: 5346: 4891: 4701: 4279: 4236: 4175: 4173: 4169:intersection 4168: 4166: 3987: 3907: 3828: 3826: 3780:if it has a 3777: 3731: 3729: 3567:cardinality. 3537: 3479: 3434: 3375: 3371: 3349: 3258:and rays of 3224: 3187: 3162: 3137: 3133: 3112:. The space 3032:which makes 2977: 2763: 2755: 2753: 2747: 2721: 2615:is connected 2326:Banach space 2166:real numbers 1505: 1476: 1473: 1251: 880: 704: 639: 603: 341: 328: 303:disconnected 300: 275: 263: 230: 197: 175: 167:open subsets 148: 138: 132:has genus 4. 129: 125: 121: 117: 105: 101: 98:disconnected 97: 73: 69: 65: 61: 57: 53: 36: 29: 6402:Wikiversity 6319:Key results 5031:, and thus 4115:, with the 3378:if any two 2788:to a point 2408:If a space 2320:, e.g. any 1635:containing 1595:containing 927:: they are 455:with empty 410:clopen sets 145:mathematics 6454:Categories 6248:CW complex 6189:Continuity 6179:Closed set 6138:cohomology 6041:2010-05-17 5779:References 5762:-connected 5682:connected. 4984:. Because 3935:, such as 3735:at a point 3163:-connected 3028:under the 2666:idempotent 2590:local ring 2403:Cantor set 2137:connected. 1655:such that 1504:is called 942:singletons 510:continuous 260:-connected 116:0), while 6427:geometric 6422:algebraic 6273:Cobordism 6209:Hausdorff 6204:connected 6121:Geometric 6111:Continuum 6101:Algebraic 6009:EMS Press 5988:MathWorld 5406:→ 5241:∩ 5223:∪ 5205:∪ 5174:∪ 5156:∪ 5125:∪ 5107:∪ 4962:∪ 4936:∪ 4903:∪ 4843:∪ 4743:∖ 4717:⊇ 4630:∪ 4591:∪ 4517:∅ 4514:≠ 4495:∩ 4476:∀ 4453:∅ 4450:≠ 4437:∩ 4412:∀ 4385:∅ 4382:≠ 4369:⋂ 4207:∪ 4083:∈ 4049:⁡ 4027:∪ 3958:∪ 3911:separated 3824:is open. 3655:× 3604:× 3493:Δ 3418:→ 3388:embedding 3256:intervals 3227:real line 3204:∗ 3190:long line 2851:from the 2675:≠ 2556:⁡ 2476:⁡ 2269:≥ 2240:≥ 2033:∪ 1979:∪ 1743:Hausdorff 1574:open sets 1425:Γ 1421:⊂ 1412:Γ 1331:Γ 1261:Γ 1234:∈ 1215:∈ 1105:∈ 1053:∈ 905:partition 867:⊆ 858:inclusion 797:⊆ 337:empty set 329:connected 164:non-empty 124:are not: 108:are also 76:(made of 6392:Wikibook 6370:Category 6258:Manifold 6226:Homotopy 6184:Interior 6175:Open set 6133:Homology 6082:Topology 5959:(2000). 5869:(1968). 5705:See also 5677:Since a 5528:manifold 5511:quotient 5341:Theorems 3350:A space 3218:and the 2229:, where 1788:standard 1749:Examples 1433:′ 1376:(called 1339:′ 929:disjoint 907:of  457:boundary 206:subspace 161:disjoint 141:topology 68:are all 6417:general 6219:uniform 6199:compact 6150:Digital 5814:2321676 5551:5-cycle 5518:product 5516:Every 5491:closure 4120:induced 3641:is not. 3558:be the 2724:annulus 2696:(i.e., 2664:has no 2284:, then 1786:in the 1403:) Then 903:form a 854:maximal 92:, and E 78:subsets 6412:Topics 6214:metric 6089:Fields 5967:  5877:  5849:  5812:  5546:Graphs 5541:Graphs 5526:Every 5509:Every 5498:closed 5349:: Let 3480:Every 3004:is an 2618:Every 2375:Every 1354:clopen 628:, and 412:) are 333:subset 239:, and 6194:Space 6035:(PDF) 6020:(PDF) 5810:JSTOR 4889:Proof 4610:then 4176:union 3433:. An 2906:with 2808:in a 2728:disks 2622:over 1140:Then 331:. A 196:is a 157:union 151:is a 114:genus 96:) is 5965:ISBN 5875:ISBN 5847:ISBN 5584:> 5489:The 5369:and 4785:and 4702:The 4257:and 4174:The 4167:The 3864:and 3782:base 3509:path 3136:(or 2976:. A 2941:and 2765:path 2525:-by- 2462:The 2455:The 2401:The 2316:Any 2171:The 1825:and 1695:and 1615:and 1532:and 1322:and 1252:Let 1197:and 1119:> 1085:and 1067:< 1008:< 1002:< 962:< 852:The 508:All 459:are 147:, a 120:and 104:and 5802:doi 4885:). 4046:sin 3437:of 3384:arc 3374:or 3309:or 3140:or 3092:to 3008:of 2984:of 2886:to 2428:is 2350:or 2324:or 2061:of 1552:of 1380:of 726:in 532:to 208:of 139:In 88:, E 84:, E 6456:: 6028:39 6026:. 6022:. 6007:, 6001:, 5985:. 5934:. 5913:. 5896:, 5808:. 5798:85 5796:. 5701:. 5650:, 4355:is 4277:. 4234:. 4151:. 3985:. 3342:. 3222:. 2754:A 2553:GL 2473:GL 2097:A 2057:A 276:A 235:, 228:. 6074:e 6067:t 6060:v 6046:. 6044:. 5991:. 5973:. 5940:. 5919:. 5883:. 5855:. 5830:. 5816:. 5804:: 5760:n 5658:X 5638:X 5587:3 5581:n 5561:n 5474:. 5458:) 5455:X 5452:( 5449:f 5429:X 5409:Y 5403:X 5400:: 5397:f 5377:Y 5357:X 5316:X 5296:X 5276:X 5255:) 5249:1 5245:X 5236:2 5232:Z 5227:( 5219:) 5213:2 5209:X 5200:1 5196:Z 5191:( 5187:= 5182:2 5178:X 5170:) 5164:2 5160:Z 5151:1 5147:Z 5142:( 5138:= 5133:2 5129:X 5121:) 5115:1 5111:X 5104:Y 5100:( 5096:= 5093:X 5071:1 5067:X 5044:2 5040:Z 5017:1 5013:Z 4992:Y 4970:2 4966:Z 4957:1 4953:Z 4949:= 4944:1 4940:X 4933:Y 4911:1 4907:X 4900:Y 4873:i 4851:i 4847:X 4840:Y 4820:Y 4798:2 4794:X 4771:1 4767:X 4746:Y 4740:X 4720:Y 4714:X 4686:) 4683:V 4680:( 4677:q 4674:, 4671:) 4668:U 4665:( 4662:q 4642:) 4639:V 4636:( 4633:q 4627:) 4624:U 4621:( 4618:q 4608:X 4594:V 4588:U 4578:X 4564:} 4559:i 4555:X 4551:{ 4547:/ 4543:X 4509:1 4506:+ 4503:i 4499:X 4490:i 4486:X 4482:: 4479:i 4445:j 4441:X 4432:i 4428:X 4424:: 4421:j 4418:, 4415:i 4377:i 4373:X 4341:X 4321:} 4316:i 4312:X 4308:{ 4288:X 4265:V 4245:U 4222:) 4219:2 4216:, 4213:1 4210:( 4204:) 4201:1 4198:, 4195:0 4192:( 4189:= 4186:X 4137:2 4132:R 4102:} 4098:] 4095:1 4092:, 4089:0 4086:( 4080:x 4077:: 4073:) 4068:) 4062:x 4059:1 4053:( 4043:, 4040:x 4036:( 4031:{ 4024:} 4021:) 4018:0 4015:, 4012:0 4009:( 4006:{ 4003:= 4000:T 3973:) 3970:3 3967:, 3964:2 3961:( 3955:) 3952:1 3949:, 3946:0 3943:( 3922:R 3879:n 3874:C 3850:n 3845:R 3812:X 3792:X 3764:x 3744:x 3703:X 3680:X 3659:R 3652:X 3629:X 3608:R 3601:X 3578:X 3546:X 3523:0 3465:X 3445:X 3421:X 3415:] 3412:1 3409:, 3406:0 3403:[ 3400:: 3397:f 3358:X 3324:n 3319:C 3295:n 3290:R 3267:R 3237:R 3200:L 3173:X 3149:0 3120:X 3100:y 3080:x 3060:y 3040:x 3016:X 2992:X 2964:y 2961:= 2958:) 2955:1 2952:( 2949:f 2929:x 2926:= 2923:) 2920:0 2917:( 2914:f 2894:X 2874:] 2871:1 2868:, 2865:0 2862:[ 2839:f 2819:X 2796:y 2776:x 2748:R 2704:R 2684:1 2681:, 2678:0 2652:R 2630:R 2603:R 2573:) 2569:C 2565:, 2562:n 2559:( 2533:n 2513:n 2493:) 2489:R 2485:, 2482:n 2479:( 2440:X 2416:X 2398:. 2387:. 2359:C 2337:R 2299:n 2294:R 2272:3 2266:n 2246:, 2243:2 2237:n 2215:n 2210:R 2187:R 2151:R 2124:, 2121:) 2118:0 2115:, 2112:0 2109:( 2094:. 2076:n 2071:R 2042:} 2039:3 2036:{ 2030:) 2027:1 2024:, 2021:0 2018:( 1997:. 1994:] 1991:2 1988:, 1985:1 1982:( 1976:) 1973:1 1970:, 1967:0 1964:[ 1944:] 1941:2 1938:, 1935:1 1932:( 1917:) 1914:1 1911:, 1908:0 1905:[ 1883:. 1880:) 1877:2 1874:, 1871:0 1868:[ 1848:, 1845:) 1842:2 1839:, 1836:1 1833:[ 1813:) 1810:1 1807:, 1804:0 1801:[ 1774:) 1771:2 1768:, 1765:0 1762:[ 1724:Q 1703:V 1683:U 1663:X 1643:y 1623:V 1603:x 1583:U 1560:X 1540:y 1520:x 1492:X 1454:X 1429:x 1416:x 1391:. 1388:x 1364:x 1335:x 1310:, 1307:X 1287:x 1265:x 1237:B 1229:2 1225:q 1221:, 1218:A 1210:1 1206:q 1185:, 1181:Q 1160:) 1157:B 1154:, 1151:A 1148:( 1128:. 1125:} 1122:r 1116:q 1113:: 1109:Q 1102:q 1099:{ 1096:= 1093:B 1073:} 1070:r 1064:q 1061:: 1057:Q 1050:q 1047:{ 1044:= 1041:A 1021:, 1016:2 1012:q 1005:r 997:1 993:q 970:2 966:q 957:1 953:q 915:X 891:X 840:. 837:x 817:X 777:; 774:x 754:X 734:X 714:x 691:x 671:, 668:X 648:x 612:X 600:. 584:} 581:1 578:, 575:0 572:{ 552:} 549:1 546:, 543:0 540:{ 520:X 489:X 467:X 443:X 420:X 396:X 373:X 350:X 315:X 287:X 248:n 216:X 184:X 130:D 126:C 122:D 118:C 112:( 106:B 102:A 94:4 90:3 86:2 82:1 80:E 74:E 66:D 62:C 58:B 54:A 39:² 37:R 20:)

Index

Path-connected

subsets
simply connected
genus
topology
mathematics
topological space
union
disjoint
non-empty
open subsets
topological properties
subspace
path connected
simply connected
n {\displaystyle n} -connected
locally connected
topological space
subset
empty set
clopen sets
boundary
separated sets
continuous
discrete topology
Frigyes Riesz
Felix Hausdorff
maximal
inclusion

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