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Topological space

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6735: 1859: 6518: 6756: 6724: 6793: 6766: 6746: 197:, which in section 3 defines the curved surface in a similar manner to the modern topological understanding: "A curved surface is said to possess continuous curvature at one of its points A, if the direction of all the straight lines drawn from A to points of the surface at an infinitesimal distance from A are deflected infinitesimally from one and the same plane passing through A." 4216: 3839:(also called the indiscrete topology), in which only the empty set and the whole space are open. Every sequence and net in this topology converges to every point of the space. This example shows that in general topological spaces, limits of sequences need not be unique. However, often topological spaces must be 5143:
we can introduce the discrete topology, under which the algebraic operations are continuous functions. For any such structure that is not finite, we often have a natural topology compatible with the algebraic operations, in the sense that the algebraic operations are still continuous. This leads to
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mappings. For example, in finite products, a basis for the product topology consists of all products of open sets. For infinite products, there is the additional requirement that in a basic open set, all but finitely many of its projections are the entire space.
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is strictly finer than the Euclidean topology defined above; a sequence converges to a point in this topology if and only if it converges from above in the Euclidean topology. This example shows that a set may have many distinct topologies defined on it.
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or basis for the topology, meaning that every open set is a union of some collection of sets from the base. In particular, this means that a set is open if there exists an open interval of non zero radius about every point in the set. More generally, the
5621:. A topological property is a property of spaces that is invariant under homeomorphisms. To prove that two spaces are not homeomorphic it is sufficient to find a topological property not shared by them. Examples of such properties include 1402:
The open sets then satisfy the axioms given below in the next definition of a topological space. Conversely, when given the open sets of a topological space, the neighbourhoods satisfying the above axioms can be recovered by defining
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There are many other equivalent ways to define a topological space: in other words the concepts of neighbourhood, or that of open or closed sets can be reconstructed from other starting points and satisfy the correct axioms.
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seem to be the first to realize that the main problem about the topology of (compact) surfaces is to find invariants (preferably numerical) to decide the equivalence of surfaces, that is, to decide whether two surfaces are
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a topology, because (for example) the union of all finite sets not containing zero is not finite and therefore not a member of the family of finite sets. The union of all finite sets not containing zero is also not all of
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A proof that relies only on the existence of certain open sets will also hold for any finer topology, and similarly a proof that relies only on certain sets not being open applies to any coarser topology. The terms
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The first three axioms for neighbourhoods have a clear meaning. The fourth axiom has a very important use in the structure of the theory, that of linking together the neighbourhoods of different points of
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in 1847, although he had used the term in correspondence some years earlier instead of previously used "Analysis situs". The foundation of this science, for a space of any dimension, was created by
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Although very general, the concept of topological spaces is fundamental, and used in virtually every branch of modern mathematics. The study of topological spaces in their own right is called
6235: 5480: 265: 3875:, in which a set is defined as open if it is either empty or its complement is countable. When the set is uncountable, this topology serves as a counterexample in many situations. 759: 5391: 4796: 4618: 4003: 5241: 4108: 4042: 525: 469: 5209: 5129: 5067: 5034: 3725: 2754: 2573: 2365: 2153: 832: 672: 620: 573: 392: 5096: 4967: 2826: 2659: 1222: 4993: 3937: 2796: 1848: 1783: 1264: 4076: 3282: 3221: 3160: 1921: 3248: 3187: 3130: 2714: 1819: 4349: 4171: 3566: 5424: 5318: 4128: 3961: 2069: 2037: 2005: 1510: 788: 167: 5598: 4698: 4148: 3915: 3598: 2849: 1705: 1660: 1611: 971: 6018: 5991: 5568: 4906: 4668: 2984: 2941: 2774: 2095: 1973: 1947: 1880: 1728: 1682: 1637: 1548: 3647: 3831:
A given set may have many different topologies. If a set is given a different topology, it is viewed as a different topological space. Any set can be given the
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in which every subset is open. The only convergent sequences or nets in this topology are those that are eventually constant. Also, any set can be given the
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formalizing the concept of closeness. There are several equivalent definitions of a topology, the most commonly used of which is the definition through
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are also used in the literature, but with little agreement on the meaning, so one should always be sure of an author's convention when reading.
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can be given a metric topology, in which the basic open sets are open balls defined by the metric. This is the standard topology on any
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of every open set is open. This is an attempt to capture the intuition that there are no "jumps" or "separations" in the function. A
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is a variant of the Vietoris topology, and is named after mathematician James Fell. It is generated by the following basis: for every
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are endowed with topologies that are defined by specifying when a particular sequence of functions converges to the zero function.
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if there exists a homeomorphism between them. From the standpoint of topology, homeomorphic spaces are essentially identical.
182: 3854:. Finite spaces are sometimes used to provide examples or counterexamples to conjectures about topological spaces in general. 6353: 6211: 3783: 86: 6676: 6401: 6177: 5531: 6822: 6396: 6328: 5702: 310: 63: 6684: 237: 205: 5453: 6817: 5822: 5537: 5394: 4276: 3023: 3019: 999: 6755: 6483: 6364: 6079: 5646: 5622: 5149: 4268: 3851: 3787: 3100: 623: 5649:– The system of all open sets of a given topological space ordered by inclusion is a complete Heyting algebra. 1882:
be denoted with the circles, here are four examples and two non-examples of topologies on the three-point set
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in which the open sets are the intersections of the open sets of the larger space with the subset. For any
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in which the open sets are the empty set and the sets whose complement is finite. This is the smallest
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Many topologies can be defined on a set to form a topological space. When every open set of a topology
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has a topology native to it, and this can be extended to vector spaces over that field.
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is the simplest non-discrete topological space. It has important relations to the
174: 129: 98: 5853: 4267:, which is generated by the inverse images of open sets of the factors under the 3794:
are continuous functions. The attempt to classify the objects of this category (
17: 6749: 6661: 6148: 6063: 5164: 5157: 4970: 221: 31: 6605: 6536: 6495: 6218:, (Graduate Texts in Mathematics), Springer; 1st edition (September 5, 1997). 5541: 5248: 4352: 3847: 2865: 6630: 6231: 3756: 3031: 2600: 1567: 6155:(Graduate Texts in Mathematics), Springer; 1st edition (October 17, 1997). 5765: 5366:{\displaystyle \operatorname {cl} \{x\}\subseteq \operatorname {cl} \{y\},} 3293:
are sometimes used in place of finer and coarser, respectively. The terms
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A standard example of such a system of neighbourhoods is for the real line
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is shown by the fact that there are several equivalent definitions of this
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Unter einem m e t r i s c h e n   R a u m e verstehen wir eine Menge
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consists of the so-called "marked metric graph structures" of volume 1 on
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Using these axioms, another way to define a topological space is as a set
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has a natural topology that generalizes many of the geometric aspects of
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we construct a basis set consisting of all subsets of the union of the
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This relates easily to the usual definition in analysis. Equivalently,
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suited for the application. The most commonly used is that in terms of
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first expressed the idea that a surface is a topological space that is
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have a standard topology in which the basic open sets are open balls.
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As this definition of a topology is the most commonly used, the set
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is continuous. A common example of a quotient topology is when an
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relating the number of vertices (V), edges (E) and faces (F) of a
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The intersection of any collection of closed sets is also closed.
177:. The study and generalization of this formula, specifically by 6412: 1923:
The bottom-left example is not a topology because the union of
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The union of any finite number of closed sets is also closed.
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on the set of all non-empty subsets of a topological space
3067:. A topology is completely determined if for every net in 810:
belongs to every one of its neighbourhoods with respect to
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is defined but cannot necessarily be measured by a numeric
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A Guide to the Classification Theorem for Compact Surfaces
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Another way to define a topological space is by using the
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It has been suggested that portions of this section be
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The collection of all topologies on a given fixed set
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Every subset of a topological space can be given the
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Pages displaying wikidata descriptions as a fallback
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Pages displaying wikidata descriptions as a fallback
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of topological spaces, the product can be given the
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The intersection of any finite number of members of
6675: 6639: 6525: 6446: 6072:"Moduli of graphs and automorphisms of free groups" 3477:is the meet of the collection of all topologies on 255:in 1914 in his seminal "Principles of Set Theory". 6275:, Prentice Hall; 2nd edition (December 28, 1999). 6012: 5985: 5815: 5714: â€“ Mathematical set with some added structure 5592: 5562: 5497: 5474: 5442: 5418: 5385: 5365: 5312: 5235: 5203: 5123: 5090: 5061: 5028: 4987: 4961: 4900: 4873: 4853: 4833: 4810: 4790: 4744: 4724: 4692: 4662: 4635: 4612: 4566: 4542: 4508: 4488: 4461: 4441: 4417: 4390: 4370: 4343: 4311: 4291: 4165: 4142: 4122: 4102: 4070: 4036: 3997: 3955: 3931: 3909: 3739: 3719: 3681: 3661: 3641: 3612: 3592: 3560: 3512: 3489: 3469: 3445: 3422: 3398: 3375: 3316: 3276: 3242: 3215: 3181: 3154: 3124: 3079: 3049: 2998: 2978: 2958: 2935: 2915: 2885: 2843: 2820: 2790: 2768: 2748: 2708: 2676: 2653: 2618: 2591: 2567: 2512: 2489: 2469: 2359: 2304: 2281: 2261: 2175: 2147: 2089: 2063: 2031: 1999: 1967: 1941: 1915: 1874: 1842: 1813: 1777: 1749: 1722: 1699: 1676: 1654: 1631: 1605: 1582: 1542: 1504: 1475: 1455: 1435: 1415: 1394: 1371: 1347: 1327: 1305: 1282: 1258: 1236: 1216: 1189: 1162: 1139: 1119: 1099: 1079: 1059: 1037: 1014: 988: 965: 935: 912: 892: 869: 849: 826: 802: 782: 753: 714: 694: 666: 642: 614: 589: 567: 543: 519: 486: 463: 430: 410: 386: 370:, though they can be any mathematical object. Let 358: 338: 161: 77:A topological space is the most general type of a 4554:, is generated by the following basis: for every 4183:since it is locally Euclidean. Similarly, every 308:, but perhaps more intuitive is that in terms of 74:, which is easier than the others to manipulate. 6022:Proceedings of the American Mathematical Society 5243:the closed sets of the Zariski topology are the 4706:on the set of all non-empty closed subsets of a 5684: â€“ Semicontinuity for set-valued functions 4926:, a precise notion of distance between points. 4516:is then the natural projection onto the set of 5852:(1914) . "Punktmengen in allgemeinen Räumen". 5613:Topological spaces can be broadly classified, 4944:There are many ways of defining a topology on 2986:are the closed sets, and their complements in 58:, along with an additional structure called a 50:. More specifically, a topological space is a 6424: 5747:Introduction to metric and topological spaces 3846:There exist numerous topologies on any given 93:. Common types of topological spaces include 27:Mathematical space with a notion of closeness 8: 5475:{\displaystyle \{\varnothing \}\cup \Gamma } 5463: 5457: 5357: 5351: 5339: 5333: 4670:that have non-empty intersections with each 2559: 2535: 2464: 2455: 2437: 2431: 2419: 2413: 2401: 2395: 2389: 2380: 2351: 2327: 2256: 2244: 2238: 2235: 2211: 2205: 2202: 2199: 2139: 2115: 2084: 2078: 2058: 2046: 2026: 2014: 1994: 1982: 1962: 1956: 1936: 1930: 1907: 1889: 6257:, McGraw-Hill; 1st edition (June 1, 1968). 3763:is also continuous. Two spaces are called 2776:of all finite subsets of the integers plus 2289:required by the axioms forms a topology on 1290:if it includes an open interval containing 346:be a (possibly empty) set. The elements of 286:Axiomatic foundations of topological spaces 6792: 6765: 6431: 6417: 6409: 4881:and have nonempty intersections with each 6247:General investigations of curved surfaces 6198:(3rd edition of differently titled books) 6171:Elements of Mathematics: General Topology 6004: 5998: 5977: 5971: 5966:Anderson, B. A.; Stewart, D. G. (1969). " 5928: 5916: 5805:J. Stillwell, Mathematics and its history 5793: 5581: 5575: 5554: 5548: 5487: 5455: 5435: 5411: 5378: 5325: 5299: 5224: 5220: 5219: 5216: 5195: 5191: 5190: 5187: 5115: 5111: 5110: 5107: 5081: 5080: 5078: 5053: 5049: 5048: 5045: 5020: 5016: 5015: 5012: 4999:. The set of all open intervals forms a 4981: 4980: 4978: 4952: 4951: 4949: 4941:this topology is the same for all norms. 4892: 4886: 4866: 4846: 4823: 4803: 4782: 4763: 4757: 4737: 4717: 4681: 4675: 4654: 4648: 4625: 4604: 4585: 4579: 4559: 4532: 4501: 4478: 4454: 4434: 4407: 4383: 4363: 4324: 4304: 4284: 4155: 4135: 4115: 4083: 4048: 4014: 3972: 3948: 3925: 3924: 3922: 3887: 3805:has motivated areas of research, such as 3732: 3694: 3674: 3654: 3625: 3605: 3579: 3541: 3502: 3482: 3462: 3435: 3415: 3388: 3350: 3333: 3309: 3265: 3259: 3234: 3228: 3204: 3198: 3173: 3167: 3143: 3137: 3116: 3110: 3072: 3039: 2991: 2971: 2948: 2928: 2908: 2878: 2833: 2811: 2810: 2808: 2784: 2783: 2781: 2761: 2739: 2738: 2730: 2689: 2666: 2631: 2608: 2584: 2527: 2502: 2482: 2372: 2319: 2294: 2274: 2191: 2168: 2107: 2076: 2044: 2012: 1980: 1954: 1928: 1887: 1867: 1829: 1794: 1764: 1739: 1715: 1689: 1669: 1644: 1624: 1595: 1575: 1535: 1488: 1468: 1448: 1428: 1408: 1384: 1364: 1340: 1320: 1295: 1275: 1252: 1251: 1249: 1229: 1207: 1206: 1204: 1179: 1152: 1132: 1112: 1092: 1072: 1052: 1027: 1007: 978: 952: 925: 905: 882: 862: 842: 818: 817: 815: 795: 766: 736: 735: 727: 707: 687: 658: 657: 655: 635: 606: 605: 603: 582: 559: 558: 556: 536: 502: 501: 499: 476: 446: 445: 443: 423: 403: 378: 377: 375: 351: 331: 251:Topological spaces were first defined by 195:General investigations of curved surfaces 136: 6306:, Macdonald Technical & Scientific, 6290:, Springer; 1st edition (July 6, 2005). 5731: 5678: â€“ Type of topological vector space 5724: 5690: â€“ In mathematics, vector subspace 5460: 5255:Topological spaces with order structure 2383: 2247: 1834: 3063:is a generalisation of the concept of 3022:, which define the closed sets as the 2661:consisting of all possible subsets of 2269:consisting of only the two subsets of 1730:of the open sets is commonly called a 790:In other words, each point of the set 754:{\displaystyle N\in {\mathcal {N}}(x)} 6332:, Holt, Rinehart and Winston (1970). 5904: 5892: 5778: 3568:between topological spaces is called 1562:and satisfying the following axioms: 7: 6255:Schaum's Outline of General Topology 5836:participating institution membership 5603:Classification of topological spaces 4473:is defined on the topological space 3878:The real line can also be given the 1379:is a neighbourhood of all points in 1147:is a neighbourhood of each point of 259:had been defined earlier in 1906 by 5393:denotes an operator satisfying the 5386:{\displaystyle \operatorname {cl} } 4791:{\displaystyle U_{1},\ldots ,U_{n}} 4613:{\displaystyle U_{1},\ldots ,U_{n}} 4191:inherits a natural topology from . 3998:{\displaystyle \gamma =[0,\gamma )} 2684:In this case the topological space 1615:Any arbitrary (finite or infinite) 62:, which can be defined as a set of 6288:A Taste of Topology (Universitext) 6132:Undergraduate Texts in Mathematics 5655: â€“ Type of mathematical space 5469: 5413: 2639: 220:The subject is clearly defined by 81:that allows for the definition of 25: 5672: â€“ Type of topological space 5236:{\displaystyle \mathbb {C} ^{n},} 5135:Topology from algebraic structure 5069:the basic open sets are the open 5036:can be given a topology. In the 4103:{\displaystyle (\alpha ,\gamma )} 4037:{\displaystyle (\alpha ,\beta ),} 3790:are topological spaces and whose 3383:is a collection of topologies on 1315:Given such a structure, a subset 520:{\displaystyle {\mathcal {N}}(x)} 464:{\displaystyle {\mathcal {N}}(x)} 66:for each point that satisfy some 6791: 6764: 6754: 6744: 6733: 6723: 6722: 6516: 5204:{\displaystyle \mathbb {R} ^{n}} 5174:is defined algebraically on the 5124:{\displaystyle \mathbb {C} ^{n}} 5062:{\displaystyle \mathbb {R} ^{n}} 5029:{\displaystyle \mathbb {R} ^{n}} 4378:is the collection of subsets of 4358:, then the quotient topology on 4214: 3720:{\displaystyle f(M)\subseteq N.} 2756:the set of integers, the family 877:and includes a neighbourhood of 290:The utility of the concept of a 5633:. For algebraic invariants see 5269:if and only if it is the prime 3843:where limit points are unique. 2749:{\displaystyle X=\mathbb {Z} ,} 1530:may be defined as a collection 6245:Gauss, Carl Friedrich (1827). 4335: 4227:out into articles titled 4206:Topology from other topologies 4097: 4085: 4062: 4050: 4028: 4016: 3992: 3980: 3901: 3889: 3868:topology on any infinite set. 3821:Examples of topological spaces 3784:category of topological spaces 3705: 3699: 3636: 3630: 3552: 2966:Thus the sets in the topology 2703: 2691: 2648: 2642: 2568:{\displaystyle X=\{1,2,3,4\},} 2360:{\displaystyle X=\{1,2,3,4\},} 2148:{\displaystyle X=\{1,2,3,4\},} 1808: 1796: 947:of a neighbourhood of a point 827:{\displaystyle {\mathcal {N}}} 748: 742: 667:{\displaystyle {\mathcal {N}}} 630:below are satisfied; and then 615:{\displaystyle {\mathcal {N}}} 568:{\displaystyle {\mathcal {N}}} 514: 508: 458: 452: 387:{\displaystyle {\mathcal {N}}} 322:This axiomatization is due to 246:locally like a Euclidean plane 1: 6344:Vaidyanathaswamy, R. (1960). 5945:. Pearson. pp. 317–319. 5402:Topology from other structure 5091:{\displaystyle \mathbb {C} ,} 4962:{\displaystyle \mathbb {R} ,} 3759:that is continuous and whose 3497:that contain every member of 2821:{\displaystyle \mathbb {Z} ,} 2654:{\displaystyle \tau =\wp (X)} 1217:{\displaystyle \mathbb {R} ,} 318:Definition via neighbourhoods 5750:. Oxford : Clarendon Press. 4988:{\displaystyle \mathbb {R} } 4973:. The standard topology on 3932:{\displaystyle \mathbb {R} } 3132:is also open for a topology 2791:{\displaystyle \mathbb {Z} } 1843:{\displaystyle X\setminus C} 1778:{\displaystyle C\subseteq X} 1259:{\displaystyle \mathbb {R} } 973:is again a neighbourhood of 314:and so this is given first. 6397:Encyclopedia of Mathematics 6329:Counterexamples in Topology 5703:Relatively compact subspace 4299:is a topological space and 4071:{\displaystyle [0,\beta ),} 4009:generated by the intervals 2923:together with a collection 6839: 6685:Banach fixed-point theorem 6126:Armstrong, M. A. (1983) . 5744:Sutherland, W. A. (1975). 5606: 4937:. On a finite-dimensional 4915: 4908:is a member of the basis. 4841:the set of all subsets of 4818:and for every compact set 4429:is the finest topology on 4279:is defined as follows: if 3824: 3526: 3277:{\displaystyle \tau _{2}.} 3216:{\displaystyle \tau _{1},} 3155:{\displaystyle \tau _{2},} 3098: 2855:Definition via closed sets 2497:forms another topology of 1916:{\displaystyle \{1,2,3\}.} 283: 238:James Waddell Alexander II 54:whose elements are called 6718: 6514: 6363:Willard, Stephen (2004). 6348:. Chelsea Publishing Co. 5941:Munkres, James R (2015). 5855:GrundzĂĽge der Mengenlehre 5823:Oxford English Dictionary 5395:Kuratowski closure axioms 5150:topological vector spaces 3871:Any set can be given the 3857:Any set can be given the 3852:finite topological spaces 3850:. Such spaces are called 3774:, one of the fundamental 3649:there is a neighbourhood 3243:{\displaystyle \tau _{1}} 3182:{\displaystyle \tau _{2}} 3125:{\displaystyle \tau _{1}} 3020:Kuratowski closure axioms 2709:{\displaystyle (X,\tau )} 1814:{\displaystyle (X,\tau )} 1515:Definition via open sets 1423:to be a neighbourhood of 1087:includes a neighbourhood 1002:of two neighbourhoods of 6302:Schubert, Horst (1968), 6208:, Academic Press (1969). 6173:, Addison-Wesley (1966). 6080:Inventiones Mathematicae 5647:Complete Heyting algebra 5617:homeomorphism, by their 4344:{\displaystyle f:X\to Y} 4166:{\displaystyle \gamma .} 4005:may be endowed with the 3600:and every neighbourhood 3561:{\displaystyle f:X\to Y} 3101:Comparison of topologies 3095:Comparison of topologies 38:is, roughly speaking, a 5828:Oxford University Press 5419:{\displaystyle \Gamma } 5313:{\displaystyle x\leq y} 5286:specialization preorder 5281:Specialization preorder 4922:Metric spaces embody a 4861:that are disjoint from 4123:{\displaystyle \alpha } 3956:{\displaystyle \gamma } 3430:is the intersection of 2828:and so it cannot be in 2064:{\displaystyle \{2,3\}} 2032:{\displaystyle \{1,2\}} 2000:{\displaystyle \{2,3\}} 1505:{\displaystyle x\in U.} 783:{\displaystyle x\in N.} 438:a non-empty collection 298:. Thus one chooses the 230:Johann Benedict Listing 162:{\displaystyle V-E+F=2} 6740:Mathematics portal 6640:Metrics and properties 6626:Second-countable space 6369:. Dover Publications. 6324:Seebach, J. Arthur Jr. 6183:Topology and Groupoids 6014: 5987: 5694:Quasitopological space 5619:topological properties 5594: 5593:{\displaystyle F_{n}.} 5564: 5499: 5476: 5444: 5420: 5387: 5367: 5314: 5237: 5205: 5125: 5092: 5063: 5030: 4989: 4963: 4902: 4875: 4855: 4835: 4812: 4792: 4746: 4726: 4694: 4693:{\displaystyle U_{i}.} 4664: 4637: 4614: 4568: 4544: 4510: 4490: 4463: 4443: 4419: 4392: 4372: 4345: 4313: 4293: 4167: 4144: 4143:{\displaystyle \beta } 4124: 4104: 4072: 4038: 3999: 3957: 3933: 3911: 3910:{\displaystyle [a,b).} 3741: 3721: 3683: 3663: 3643: 3614: 3594: 3593:{\displaystyle x\in X} 3562: 3514: 3491: 3471: 3447: 3424: 3400: 3377: 3318: 3278: 3244: 3217: 3183: 3156: 3126: 3081: 3051: 3000: 2980: 2960: 2937: 2917: 2887: 2845: 2844:{\displaystyle \tau .} 2822: 2792: 2770: 2750: 2710: 2678: 2655: 2620: 2593: 2569: 2514: 2491: 2471: 2361: 2306: 2283: 2263: 2177: 2149: 2098: 2091: 2065: 2033: 2001: 1969: 1943: 1917: 1876: 1854:Examples of topologies 1844: 1815: 1779: 1751: 1724: 1701: 1700:{\displaystyle \tau .} 1678: 1656: 1655:{\displaystyle \tau .} 1633: 1607: 1606:{\displaystyle \tau .} 1584: 1544: 1506: 1477: 1457: 1437: 1417: 1396: 1373: 1349: 1329: 1307: 1284: 1260: 1238: 1218: 1191: 1164: 1141: 1121: 1101: 1081: 1061: 1039: 1022:is a neighbourhood of 1016: 990: 967: 966:{\displaystyle x\in X} 937: 920:is a neighbourhood of 914: 894: 871: 851: 828: 804: 784: 755: 716: 702:is a neighbourhood of 696: 668: 644: 624:neighbourhood topology 616: 591: 569: 545: 521: 488: 465: 432: 412: 388: 360: 340: 296:mathematical structure 273: 189:of topology. In 1827, 163: 6153:Topology and Geometry 6015: 6013:{\displaystyle T_{1}} 5988: 5986:{\displaystyle T_{1}} 5794:Gallier & Xu 2013 5595: 5565: 5563:{\displaystyle F_{n}} 5500: 5477: 5445: 5421: 5388: 5368: 5315: 5238: 5206: 5126: 5093: 5064: 5031: 4990: 4964: 4903: 4901:{\displaystyle U_{i}} 4876: 4856: 4836: 4813: 4793: 4747: 4727: 4695: 4665: 4663:{\displaystyle U_{i}} 4638: 4615: 4569: 4545: 4511: 4491: 4464: 4444: 4420: 4393: 4373: 4346: 4314: 4294: 4200:theory of computation 4168: 4145: 4125: 4105: 4073: 4039: 4000: 3958: 3934: 3912: 3747:is continuous if the 3742: 3722: 3684: 3664: 3644: 3615: 3595: 3563: 3515: 3492: 3472: 3448: 3425: 3401: 3378: 3319: 3279: 3245: 3218: 3184: 3157: 3127: 3082: 3052: 3001: 2981: 2979:{\displaystyle \tau } 2961: 2943:of closed subsets of 2938: 2936:{\displaystyle \tau } 2918: 2888: 2846: 2823: 2793: 2771: 2769:{\displaystyle \tau } 2751: 2711: 2679: 2656: 2621: 2594: 2570: 2515: 2492: 2472: 2362: 2307: 2284: 2264: 2178: 2150: 2092: 2090:{\displaystyle \{2\}} 2066: 2034: 2002: 1970: 1968:{\displaystyle \{3\}} 1944: 1942:{\displaystyle \{2\}} 1918: 1877: 1875:{\displaystyle \tau } 1861: 1845: 1816: 1780: 1752: 1725: 1723:{\displaystyle \tau } 1702: 1679: 1677:{\displaystyle \tau } 1657: 1634: 1632:{\displaystyle \tau } 1608: 1585: 1545: 1543:{\displaystyle \tau } 1507: 1478: 1463:includes an open set 1458: 1438: 1418: 1397: 1374: 1350: 1330: 1308: 1285: 1261: 1239: 1219: 1192: 1165: 1142: 1122: 1102: 1082: 1062: 1040: 1017: 991: 968: 938: 915: 895: 872: 852: 829: 805: 785: 756: 717: 697: 669: 645: 617: 592: 570: 546: 522: 489: 466: 433: 413: 389: 361: 341: 164: 6695:Invariance of domain 6647:Euler characteristic 6621:Bundle (mathematics) 6253:Lipschutz, Seymour; 5997: 5970: 5609:Topological property 5574: 5547: 5486: 5454: 5434: 5410: 5377: 5324: 5298: 5215: 5186: 5106: 5077: 5044: 5011: 4995:is generated by the 4977: 4948: 4885: 4865: 4845: 4822: 4802: 4756: 4736: 4716: 4674: 4647: 4624: 4578: 4558: 4531: 4500: 4477: 4471:equivalence relation 4453: 4433: 4425:In other words, the 4406: 4382: 4362: 4323: 4303: 4283: 4154: 4134: 4114: 4082: 4047: 4013: 3971: 3947: 3921: 3886: 3880:lower limit topology 3873:cocountable topology 3782:, which denotes the 3731: 3693: 3673: 3653: 3642:{\displaystyle f(x)} 3624: 3604: 3578: 3540: 3523:Continuous functions 3501: 3481: 3461: 3434: 3414: 3387: 3332: 3308: 3258: 3227: 3197: 3166: 3136: 3109: 3071: 3038: 2990: 2970: 2947: 2927: 2907: 2877: 2832: 2807: 2780: 2760: 2729: 2688: 2665: 2630: 2626:which is the family 2607: 2583: 2526: 2501: 2481: 2371: 2318: 2293: 2273: 2190: 2167: 2106: 2075: 2043: 2011: 1979: 1953: 1927: 1886: 1866: 1828: 1793: 1763: 1738: 1714: 1688: 1668: 1643: 1623: 1594: 1574: 1534: 1487: 1467: 1447: 1427: 1407: 1383: 1363: 1339: 1319: 1294: 1274: 1248: 1228: 1203: 1178: 1151: 1131: 1111: 1091: 1071: 1051: 1026: 1006: 977: 951: 924: 904: 881: 861: 841: 814: 794: 765: 726: 706: 686: 654: 634: 602: 581: 555: 535: 498: 475: 442: 422: 402: 374: 350: 330: 191:Carl Friedrich Gauss 135: 6705:Tychonoff's theorem 6700:PoincarĂ© conjecture 6454:General (point-set) 6392:"Topological space" 6093:1986InMat..84...91C 5826:(Online ed.). 5712:Space (mathematics) 5513:functional analysis 4935:normed vector space 4518:equivalence classes 3529:Continuous function 3089:accumulation points 3006:are the open sets. 1266:is defined to be a 366:are usually called 6823:Topological spaces 6690:De Rham cohomology 6611:Polyhedral complex 6601:Simplicial complex 6216:Algebraic Topology 6101:10.1007/BF01388734 6010: 5983: 5635:algebraic topology 5590: 5560: 5498:{\displaystyle X.} 5495: 5472: 5440: 5416: 5383: 5363: 5310: 5290:canonical preorder 5283:: In a space the 5271:spectrum of a ring 5233: 5201: 5176:spectrum of a ring 5146:topological groups 5121: 5088: 5059: 5026: 4985: 4959: 4898: 4871: 4851: 4834:{\displaystyle K,} 4831: 4808: 4788: 4742: 4722: 4690: 4660: 4636:{\displaystyle X,} 4633: 4610: 4564: 4543:{\displaystyle X,} 4540: 4506: 4489:{\displaystyle X.} 4486: 4459: 4439: 4418:{\displaystyle f.} 4415: 4388: 4368: 4341: 4309: 4289: 4189:simplicial complex 4163: 4140: 4120: 4100: 4068: 4034: 3995: 3953: 3929: 3907: 3827:List of topologies 3737: 3717: 3679: 3659: 3639: 3610: 3590: 3558: 3513:{\displaystyle F.} 3510: 3487: 3467: 3446:{\displaystyle F,} 3443: 3420: 3399:{\displaystyle X,} 3396: 3373: 3314: 3274: 3240: 3213: 3179: 3152: 3122: 3077: 3050:{\displaystyle X.} 3047: 2996: 2976: 2959:{\displaystyle X.} 2956: 2933: 2913: 2883: 2873:The empty set and 2841: 2818: 2788: 2766: 2746: 2706: 2677:{\displaystyle X.} 2674: 2651: 2619:{\displaystyle X,} 2616: 2589: 2565: 2513:{\displaystyle X.} 2510: 2487: 2477:of six subsets of 2467: 2357: 2305:{\displaystyle X.} 2302: 2279: 2259: 2173: 2145: 2099: 2087: 2061: 2029: 1997: 1965: 1939: 1913: 1872: 1840: 1811: 1775: 1750:{\displaystyle X.} 1747: 1720: 1697: 1674: 1652: 1629: 1603: 1580: 1540: 1502: 1473: 1453: 1433: 1413: 1395:{\displaystyle U.} 1392: 1369: 1345: 1325: 1306:{\displaystyle x.} 1303: 1280: 1256: 1234: 1214: 1190:{\displaystyle X.} 1187: 1163:{\displaystyle M.} 1160: 1137: 1117: 1097: 1077: 1057: 1047:Any neighbourhood 1038:{\displaystyle x.} 1035: 1012: 989:{\displaystyle x.} 986: 963: 936:{\displaystyle x.} 933: 910: 893:{\displaystyle x,} 890: 867: 847: 824: 800: 780: 751: 712: 692: 664: 640: 612: 587: 577:neighbourhoods of 565: 541: 517: 487:{\displaystyle X.} 484: 461: 428: 408: 398:assigning to each 384: 356: 336: 159: 110:point-set topology 79:mathematical space 6805: 6804: 6594:fundamental group 6167:Bourbaki, Nicolas 5952:978-93-325-4953-1 5919:, definition 2.1. 5834:(Subscription or 5659:Convergence space 5631:separation axioms 5482:is a topology on 5443:{\displaystyle X} 5180:algebraic variety 5154:topological rings 5144:concepts such as 5141:algebraic objects 4874:{\displaystyle K} 4854:{\displaystyle X} 4811:{\displaystyle X} 4745:{\displaystyle n} 4725:{\displaystyle X} 4567:{\displaystyle n} 4525:Vietoris topology 4509:{\displaystyle f} 4462:{\displaystyle f} 4442:{\displaystyle Y} 4427:quotient topology 4391:{\displaystyle Y} 4371:{\displaystyle Y} 4319:is a set, and if 4312:{\displaystyle Y} 4292:{\displaystyle X} 4257:subspace topology 4253: 4252: 4248: 4230:Vietoris topology 3917:This topology on 3859:cofinite topology 3833:discrete topology 3740:{\displaystyle f} 3682:{\displaystyle x} 3662:{\displaystyle M} 3613:{\displaystyle N} 3490:{\displaystyle X} 3470:{\displaystyle F} 3423:{\displaystyle F} 3317:{\displaystyle X} 3080:{\displaystyle X} 3010:Other definitions 2999:{\displaystyle X} 2916:{\displaystyle X} 2886:{\displaystyle X} 2592:{\displaystyle X} 2577:discrete topology 2490:{\displaystyle X} 2282:{\displaystyle X} 2176:{\displaystyle X} 1590:itself belong to 1583:{\displaystyle X} 1476:{\displaystyle U} 1456:{\displaystyle N} 1436:{\displaystyle x} 1416:{\displaystyle N} 1372:{\displaystyle U} 1355:is defined to be 1348:{\displaystyle X} 1328:{\displaystyle U} 1283:{\displaystyle x} 1270:of a real number 1237:{\displaystyle N} 1140:{\displaystyle N} 1120:{\displaystyle x} 1100:{\displaystyle M} 1080:{\displaystyle x} 1060:{\displaystyle N} 1015:{\displaystyle x} 913:{\displaystyle N} 870:{\displaystyle X} 850:{\displaystyle N} 803:{\displaystyle X} 715:{\displaystyle x} 695:{\displaystyle N} 676:topological space 643:{\displaystyle X} 590:{\displaystyle x} 544:{\displaystyle x} 431:{\displaystyle X} 411:{\displaystyle x} 359:{\displaystyle X} 339:{\displaystyle X} 187:boosted the study 173:, and hence of a 171:convex polyhedron 40:geometrical space 36:topological space 18:Vietoris topology 16:(Redirected from 6830: 6818:General topology 6795: 6794: 6768: 6767: 6758: 6748: 6738: 6737: 6726: 6725: 6520: 6433: 6426: 6419: 6410: 6405: 6380: 6366:General Topology 6359: 6316: 6250: 6241: 6197: 6145: 6113: 6112: 6076: 6060: 6054: 6053: 6019: 6017: 6016: 6011: 6009: 6008: 5993:-complements of 5992: 5990: 5989: 5984: 5982: 5981: 5963: 5957: 5956: 5938: 5932: 5926: 5920: 5914: 5908: 5902: 5896: 5890: 5884: 5883: 5874: 5872: 5850:Hausdorff, Felix 5846: 5840: 5839: 5831: 5819: 5812: 5806: 5803: 5797: 5791: 5782: 5776: 5770: 5769: 5741: 5735: 5729: 5708: 5699: 5599: 5597: 5596: 5591: 5586: 5585: 5569: 5567: 5566: 5561: 5559: 5558: 5509:linear operators 5504: 5502: 5501: 5496: 5481: 5479: 5478: 5473: 5449: 5447: 5446: 5441: 5425: 5423: 5422: 5417: 5392: 5390: 5389: 5384: 5372: 5370: 5369: 5364: 5319: 5317: 5316: 5311: 5242: 5240: 5239: 5234: 5229: 5228: 5223: 5210: 5208: 5207: 5202: 5200: 5199: 5194: 5172:Zariski topology 5130: 5128: 5127: 5122: 5120: 5119: 5114: 5097: 5095: 5094: 5089: 5084: 5068: 5066: 5065: 5060: 5058: 5057: 5052: 5035: 5033: 5032: 5027: 5025: 5024: 5019: 5006:Euclidean spaces 4994: 4992: 4991: 4986: 4984: 4968: 4966: 4965: 4960: 4955: 4907: 4905: 4904: 4899: 4897: 4896: 4880: 4878: 4877: 4872: 4860: 4858: 4857: 4852: 4840: 4838: 4837: 4832: 4817: 4815: 4814: 4809: 4798:of open sets in 4797: 4795: 4794: 4789: 4787: 4786: 4768: 4767: 4751: 4749: 4748: 4743: 4731: 4729: 4728: 4723: 4699: 4697: 4696: 4691: 4686: 4685: 4669: 4667: 4666: 4661: 4659: 4658: 4642: 4640: 4639: 4634: 4620:of open sets in 4619: 4617: 4616: 4611: 4609: 4608: 4590: 4589: 4573: 4571: 4570: 4565: 4552:Leopold Vietoris 4549: 4547: 4546: 4541: 4515: 4513: 4512: 4507: 4495: 4493: 4492: 4487: 4468: 4466: 4465: 4460: 4448: 4446: 4445: 4440: 4424: 4422: 4421: 4416: 4397: 4395: 4394: 4389: 4377: 4375: 4374: 4369: 4350: 4348: 4347: 4342: 4318: 4316: 4315: 4310: 4298: 4296: 4295: 4290: 4265:product topology 4244: 4218: 4217: 4210: 4196:SierpiĹ„ski space 4181:natural topology 4172: 4170: 4169: 4164: 4150:are elements of 4149: 4147: 4146: 4141: 4129: 4127: 4126: 4121: 4109: 4107: 4106: 4101: 4077: 4075: 4074: 4069: 4043: 4041: 4040: 4035: 4004: 4002: 4001: 3996: 3962: 3960: 3959: 3954: 3938: 3936: 3935: 3930: 3928: 3916: 3914: 3913: 3908: 3841:Hausdorff spaces 3837:trivial topology 3746: 3744: 3743: 3738: 3726: 3724: 3723: 3718: 3688: 3686: 3685: 3680: 3668: 3666: 3665: 3660: 3648: 3646: 3645: 3640: 3619: 3617: 3616: 3611: 3599: 3597: 3596: 3591: 3567: 3565: 3564: 3559: 3519: 3517: 3516: 3511: 3496: 3494: 3493: 3488: 3476: 3474: 3473: 3468: 3452: 3450: 3449: 3444: 3429: 3427: 3426: 3421: 3405: 3403: 3402: 3397: 3382: 3380: 3379: 3374: 3372: 3368: 3355: 3354: 3326:complete lattice 3323: 3321: 3320: 3315: 3283: 3281: 3280: 3275: 3270: 3269: 3249: 3247: 3246: 3241: 3239: 3238: 3222: 3220: 3219: 3214: 3209: 3208: 3188: 3186: 3185: 3180: 3178: 3177: 3161: 3159: 3158: 3153: 3148: 3147: 3131: 3129: 3128: 3123: 3121: 3120: 3086: 3084: 3083: 3078: 3056: 3054: 3053: 3048: 3005: 3003: 3002: 2997: 2985: 2983: 2982: 2977: 2965: 2963: 2962: 2957: 2942: 2940: 2939: 2934: 2922: 2920: 2919: 2914: 2892: 2890: 2889: 2884: 2861:de Morgan's laws 2850: 2848: 2847: 2842: 2827: 2825: 2824: 2819: 2814: 2797: 2795: 2794: 2789: 2787: 2775: 2773: 2772: 2767: 2755: 2753: 2752: 2747: 2742: 2715: 2713: 2712: 2707: 2683: 2681: 2680: 2675: 2660: 2658: 2657: 2652: 2625: 2623: 2622: 2617: 2598: 2596: 2595: 2590: 2574: 2572: 2571: 2566: 2519: 2517: 2516: 2511: 2496: 2494: 2493: 2488: 2476: 2474: 2473: 2468: 2366: 2364: 2363: 2358: 2311: 2309: 2308: 2303: 2288: 2286: 2285: 2280: 2268: 2266: 2265: 2260: 2182: 2180: 2179: 2174: 2154: 2152: 2151: 2146: 2096: 2094: 2093: 2088: 2070: 2068: 2067: 2062: 2038: 2036: 2035: 2030: 2006: 2004: 2003: 1998: 1974: 1972: 1971: 1966: 1948: 1946: 1945: 1940: 1922: 1920: 1919: 1914: 1881: 1879: 1878: 1873: 1850:is an open set. 1849: 1847: 1846: 1841: 1820: 1818: 1817: 1812: 1784: 1782: 1781: 1776: 1756: 1754: 1753: 1748: 1729: 1727: 1726: 1721: 1706: 1704: 1703: 1698: 1683: 1681: 1680: 1675: 1661: 1659: 1658: 1653: 1638: 1636: 1635: 1630: 1612: 1610: 1609: 1604: 1589: 1587: 1586: 1581: 1557: 1549: 1547: 1546: 1541: 1529: 1511: 1509: 1508: 1503: 1482: 1480: 1479: 1474: 1462: 1460: 1459: 1454: 1442: 1440: 1439: 1434: 1422: 1420: 1419: 1414: 1401: 1399: 1398: 1393: 1378: 1376: 1375: 1370: 1354: 1352: 1351: 1346: 1334: 1332: 1331: 1326: 1312: 1310: 1309: 1304: 1289: 1287: 1286: 1281: 1265: 1263: 1262: 1257: 1255: 1243: 1241: 1240: 1235: 1223: 1221: 1220: 1215: 1210: 1196: 1194: 1193: 1188: 1169: 1167: 1166: 1161: 1146: 1144: 1143: 1138: 1126: 1124: 1123: 1118: 1106: 1104: 1103: 1098: 1086: 1084: 1083: 1078: 1066: 1064: 1063: 1058: 1044: 1042: 1041: 1036: 1021: 1019: 1018: 1013: 995: 993: 992: 987: 972: 970: 969: 964: 942: 940: 939: 934: 919: 917: 916: 911: 899: 897: 896: 891: 876: 874: 873: 868: 856: 854: 853: 848: 833: 831: 830: 825: 823: 822: 809: 807: 806: 801: 789: 787: 786: 781: 760: 758: 757: 752: 741: 740: 721: 719: 718: 713: 701: 699: 698: 693: 673: 671: 670: 665: 663: 662: 649: 647: 646: 641: 621: 619: 618: 613: 611: 610: 598:). The function 596: 594: 593: 588: 574: 572: 571: 566: 564: 563: 551:with respect to 550: 548: 547: 542: 526: 524: 523: 518: 507: 506: 494:The elements of 493: 491: 490: 485: 470: 468: 467: 462: 451: 450: 437: 435: 434: 429: 417: 415: 414: 409: 393: 391: 390: 385: 383: 382: 365: 363: 362: 357: 345: 343: 342: 337: 268: 226:Erlangen Program 181:(1789–1857) and 168: 166: 165: 160: 114:general topology 95:Euclidean spaces 21: 6838: 6837: 6833: 6832: 6831: 6829: 6828: 6827: 6808: 6807: 6806: 6801: 6732: 6714: 6710:Urysohn's lemma 6671: 6635: 6521: 6512: 6484:low-dimensional 6442: 6437: 6390: 6387: 6377: 6362: 6356: 6343: 6314: 6301: 6286:Runde, Volker; 6244: 6230:Gallier, Jean; 6229: 6212:Fulton, William 6194: 6176: 6149:Bredon, Glen E. 6142: 6125: 6122: 6117: 6116: 6074: 6068:Vogtmann, Karen 6062: 6061: 6057: 6034:10.2307/2037491 6000: 5995: 5994: 5973: 5968: 5967: 5965: 5964: 5960: 5953: 5940: 5939: 5935: 5927: 5923: 5915: 5911: 5903: 5899: 5891: 5887: 5870: 5868: 5866: 5848: 5847: 5843: 5833: 5814: 5813: 5809: 5804: 5800: 5792: 5785: 5777: 5773: 5758: 5743: 5742: 5738: 5730: 5726: 5721: 5706: 5697: 5688:Linear subspace 5670:Hausdorff space 5643: 5611: 5605: 5577: 5572: 5571: 5550: 5545: 5544: 5484: 5483: 5452: 5451: 5432: 5431: 5408: 5407: 5404: 5375: 5374: 5322: 5321: 5320:if and only if 5296: 5295: 5257: 5218: 5213: 5212: 5189: 5184: 5183: 5137: 5109: 5104: 5103: 5100:complex numbers 5075: 5074: 5047: 5042: 5041: 5014: 5009: 5008: 4975: 4974: 4946: 4945: 4920: 4914: 4888: 4883: 4882: 4863: 4862: 4843: 4842: 4820: 4819: 4800: 4799: 4778: 4759: 4754: 4753: 4734: 4733: 4714: 4713: 4708:locally compact 4677: 4672: 4671: 4650: 4645: 4644: 4622: 4621: 4600: 4581: 4576: 4575: 4556: 4555: 4529: 4528: 4498: 4497: 4475: 4474: 4451: 4450: 4431: 4430: 4404: 4403: 4398:that have open 4380: 4379: 4360: 4359: 4321: 4320: 4301: 4300: 4281: 4280: 4249: 4219: 4215: 4208: 4202:and semantics. 4152: 4151: 4132: 4131: 4112: 4111: 4080: 4079: 4045: 4044: 4011: 4010: 3969: 3968: 3967:, then the set 3945: 3944: 3919: 3918: 3884: 3883: 3866: 3829: 3823: 3811:homology theory 3807:homotopy theory 3772:category theory 3729: 3728: 3691: 3690: 3671: 3670: 3651: 3650: 3622: 3621: 3602: 3601: 3576: 3575: 3538: 3537: 3531: 3525: 3499: 3498: 3479: 3478: 3459: 3458: 3432: 3431: 3412: 3411: 3385: 3384: 3346: 3345: 3341: 3330: 3329: 3306: 3305: 3261: 3256: 3255: 3230: 3225: 3224: 3200: 3195: 3194: 3169: 3164: 3163: 3139: 3134: 3133: 3112: 3107: 3106: 3103: 3097: 3087:the set of its 3069: 3068: 3036: 3035: 3012: 2988: 2987: 2968: 2967: 2945: 2944: 2925: 2924: 2905: 2904: 2875: 2874: 2857: 2830: 2829: 2805: 2804: 2778: 2777: 2758: 2757: 2727: 2726: 2686: 2685: 2663: 2662: 2628: 2627: 2605: 2604: 2581: 2580: 2524: 2523: 2499: 2498: 2479: 2478: 2369: 2368: 2316: 2315: 2291: 2290: 2271: 2270: 2188: 2187: 2165: 2164: 2104: 2103: 2073: 2072: 2041: 2040: 2009: 2008: 1977: 1976: 1951: 1950: 1925: 1924: 1884: 1883: 1864: 1863: 1856: 1826: 1825: 1791: 1790: 1761: 1760: 1736: 1735: 1712: 1711: 1686: 1685: 1666: 1665: 1641: 1640: 1621: 1620: 1592: 1591: 1572: 1571: 1555: 1532: 1531: 1527: 1517: 1485: 1484: 1465: 1464: 1445: 1444: 1425: 1424: 1405: 1404: 1381: 1380: 1361: 1360: 1337: 1336: 1317: 1316: 1292: 1291: 1272: 1271: 1246: 1245: 1226: 1225: 1224:where a subset 1201: 1200: 1176: 1175: 1149: 1148: 1129: 1128: 1109: 1108: 1089: 1088: 1069: 1068: 1049: 1048: 1024: 1023: 1004: 1003: 975: 974: 949: 948: 922: 921: 902: 901: 879: 878: 859: 858: 857:is a subset of 839: 838: 812: 811: 792: 791: 763: 762: 724: 723: 704: 703: 684: 683: 652: 651: 632: 631: 600: 599: 579: 578: 553: 552: 533: 532: 527:will be called 496: 495: 473: 472: 440: 439: 420: 419: 400: 399: 372: 371: 348: 347: 328: 327: 324:Felix Hausdorff 320: 288: 282: 274:metrischer Raum 264: 261:Maurice FrĂ©chet 253:Felix Hausdorff 242:Hassler Whitney 133: 132: 128:discovered the 122: 28: 23: 22: 15: 12: 11: 5: 6836: 6834: 6826: 6825: 6820: 6810: 6809: 6803: 6802: 6800: 6799: 6789: 6788: 6787: 6782: 6777: 6762: 6752: 6742: 6730: 6719: 6716: 6715: 6713: 6712: 6707: 6702: 6697: 6692: 6687: 6681: 6679: 6673: 6672: 6670: 6669: 6664: 6659: 6657:Winding number 6654: 6649: 6643: 6641: 6637: 6636: 6634: 6633: 6628: 6623: 6618: 6613: 6608: 6603: 6598: 6597: 6596: 6591: 6589:homotopy group 6581: 6580: 6579: 6574: 6569: 6564: 6559: 6549: 6544: 6539: 6529: 6527: 6523: 6522: 6515: 6513: 6511: 6510: 6505: 6500: 6499: 6498: 6488: 6487: 6486: 6476: 6471: 6466: 6461: 6456: 6450: 6448: 6444: 6443: 6438: 6436: 6435: 6428: 6421: 6413: 6407: 6406: 6386: 6385:External links 6383: 6382: 6381: 6375: 6360: 6354: 6341: 6320:Steen, Lynn A. 6317: 6312: 6299: 6284: 6269:Munkres, James 6266: 6251: 6242: 6227: 6209: 6199: 6192: 6174: 6164: 6146: 6140: 6128:Basic Topology 6121: 6118: 6115: 6114: 6055: 6007: 6003: 5980: 5976: 5958: 5951: 5933: 5931:, theorem 2.6. 5929:Armstrong 1983 5921: 5917:Armstrong 1983 5909: 5907:, section 2.2. 5897: 5895:, section 2.1. 5885: 5864: 5841: 5817:"metric space" 5807: 5798: 5783: 5771: 5756: 5736: 5723: 5722: 5720: 5717: 5716: 5715: 5709: 5700: 5691: 5685: 5682:Hemicontinuity 5679: 5673: 5667: 5665:Exterior space 5662: 5656: 5650: 5642: 5639: 5629:, and various 5607:Main article: 5604: 5601: 5589: 5584: 5580: 5557: 5553: 5494: 5491: 5471: 5468: 5465: 5462: 5459: 5439: 5415: 5403: 5400: 5399: 5398: 5382: 5362: 5359: 5356: 5353: 5350: 5347: 5344: 5341: 5338: 5335: 5332: 5329: 5309: 5306: 5303: 5294:is defined by 5278: 5256: 5253: 5247:of systems of 5232: 5227: 5222: 5198: 5193: 5136: 5133: 5118: 5113: 5087: 5083: 5073:. Similarly, 5056: 5051: 5038:usual topology 5023: 5018: 4997:open intervals 4983: 4958: 4954: 4916:Main article: 4913: 4910: 4895: 4891: 4870: 4850: 4830: 4827: 4807: 4785: 4781: 4777: 4774: 4771: 4766: 4762: 4741: 4721: 4689: 4684: 4680: 4657: 4653: 4632: 4629: 4607: 4603: 4599: 4596: 4593: 4588: 4584: 4563: 4539: 4536: 4505: 4485: 4482: 4458: 4438: 4414: 4411: 4400:inverse images 4387: 4367: 4340: 4337: 4334: 4331: 4328: 4308: 4288: 4277:quotient space 4261:indexed family 4251: 4250: 4222: 4220: 4213: 4207: 4204: 4162: 4159: 4139: 4119: 4099: 4096: 4093: 4090: 4087: 4067: 4064: 4061: 4058: 4055: 4052: 4033: 4030: 4027: 4024: 4021: 4018: 4007:order topology 3994: 3991: 3988: 3985: 3982: 3979: 3976: 3965:ordinal number 3952: 3927: 3906: 3903: 3900: 3897: 3894: 3891: 3864: 3822: 3819: 3766: 3736: 3716: 3713: 3710: 3707: 3704: 3701: 3698: 3678: 3658: 3638: 3635: 3632: 3629: 3609: 3589: 3586: 3583: 3557: 3554: 3551: 3548: 3545: 3527:Main article: 3524: 3521: 3509: 3506: 3486: 3466: 3442: 3439: 3419: 3395: 3392: 3371: 3367: 3364: 3361: 3358: 3353: 3349: 3344: 3340: 3337: 3313: 3300: 3296: 3292: 3288: 3273: 3268: 3264: 3253: 3237: 3233: 3212: 3207: 3203: 3192: 3176: 3172: 3162:one says that 3151: 3146: 3142: 3119: 3115: 3099:Main article: 3096: 3093: 3091:is specified. 3076: 3046: 3043: 3011: 3008: 2995: 2975: 2955: 2952: 2932: 2912: 2901: 2900: 2897: 2894: 2882: 2856: 2853: 2852: 2851: 2840: 2837: 2817: 2813: 2801: 2786: 2765: 2745: 2741: 2737: 2734: 2723: 2719:discrete space 2705: 2702: 2699: 2696: 2693: 2673: 2670: 2650: 2647: 2644: 2641: 2638: 2635: 2615: 2612: 2588: 2564: 2561: 2558: 2555: 2552: 2549: 2546: 2543: 2540: 2537: 2534: 2531: 2520: 2509: 2506: 2486: 2466: 2463: 2460: 2457: 2454: 2451: 2448: 2445: 2442: 2439: 2436: 2433: 2430: 2427: 2424: 2421: 2418: 2415: 2412: 2409: 2406: 2403: 2400: 2397: 2394: 2391: 2388: 2385: 2382: 2379: 2376: 2356: 2353: 2350: 2347: 2344: 2341: 2338: 2335: 2332: 2329: 2326: 2323: 2312: 2301: 2298: 2278: 2258: 2255: 2252: 2249: 2246: 2243: 2240: 2237: 2234: 2231: 2228: 2225: 2222: 2219: 2216: 2213: 2210: 2207: 2204: 2201: 2198: 2195: 2172: 2162: 2144: 2141: 2138: 2135: 2132: 2129: 2126: 2123: 2120: 2117: 2114: 2111: 2097:], is missing. 2086: 2083: 2080: 2060: 2057: 2054: 2051: 2048: 2028: 2025: 2022: 2019: 2016: 1996: 1993: 1990: 1987: 1984: 1964: 1961: 1958: 1938: 1935: 1932: 1912: 1909: 1906: 1903: 1900: 1897: 1894: 1891: 1871: 1855: 1852: 1839: 1836: 1833: 1810: 1807: 1804: 1801: 1798: 1788: 1785:is said to be 1774: 1771: 1768: 1746: 1743: 1719: 1708: 1707: 1696: 1693: 1673: 1662: 1651: 1648: 1628: 1619:of members of 1613: 1602: 1599: 1579: 1539: 1516: 1513: 1501: 1498: 1495: 1492: 1472: 1452: 1432: 1412: 1391: 1388: 1368: 1344: 1324: 1302: 1299: 1279: 1269: 1254: 1233: 1213: 1209: 1186: 1183: 1171: 1170: 1159: 1156: 1136: 1116: 1096: 1076: 1056: 1045: 1034: 1031: 1011: 996: 985: 982: 962: 959: 956: 932: 929: 909: 889: 886: 866: 846: 835: 821: 799: 779: 776: 773: 770: 750: 747: 744: 739: 734: 731: 711: 691: 661: 639: 609: 597: 586: 562: 540: 530: 529:neighbourhoods 516: 513: 510: 505: 483: 480: 471:of subsets of 460: 457: 454: 449: 427: 407: 381: 369: 355: 335: 319: 316: 313: 311:neighbourhoods 307: 300:axiomatization 284:Main article: 281: 278: 234:Henri PoincarĂ© 158: 155: 152: 149: 146: 143: 140: 126:Leonhard Euler 121: 118: 64:neighbourhoods 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 6835: 6824: 6821: 6819: 6816: 6815: 6813: 6798: 6790: 6786: 6783: 6781: 6778: 6776: 6773: 6772: 6771: 6763: 6761: 6757: 6753: 6751: 6747: 6743: 6741: 6736: 6731: 6729: 6721: 6720: 6717: 6711: 6708: 6706: 6703: 6701: 6698: 6696: 6693: 6691: 6688: 6686: 6683: 6682: 6680: 6678: 6674: 6668: 6667:Orientability 6665: 6663: 6660: 6658: 6655: 6653: 6650: 6648: 6645: 6644: 6642: 6638: 6632: 6629: 6627: 6624: 6622: 6619: 6617: 6614: 6612: 6609: 6607: 6604: 6602: 6599: 6595: 6592: 6590: 6587: 6586: 6585: 6582: 6578: 6575: 6573: 6570: 6568: 6565: 6563: 6560: 6558: 6555: 6554: 6553: 6550: 6548: 6545: 6543: 6540: 6538: 6534: 6531: 6530: 6528: 6524: 6519: 6509: 6506: 6504: 6503:Set-theoretic 6501: 6497: 6494: 6493: 6492: 6489: 6485: 6482: 6481: 6480: 6477: 6475: 6472: 6470: 6467: 6465: 6464:Combinatorial 6462: 6460: 6457: 6455: 6452: 6451: 6449: 6445: 6441: 6434: 6429: 6427: 6422: 6420: 6415: 6414: 6411: 6403: 6399: 6398: 6393: 6389: 6388: 6384: 6378: 6376:0-486-43479-6 6372: 6368: 6367: 6361: 6357: 6351: 6347: 6342: 6339: 6338:0-03-079485-4 6335: 6331: 6330: 6325: 6321: 6318: 6315: 6313:0-356-02077-0 6309: 6305: 6300: 6297: 6296:0-387-25790-X 6293: 6289: 6285: 6282: 6281:0-13-181629-2 6278: 6274: 6270: 6267: 6264: 6263:0-07-037988-2 6260: 6256: 6252: 6248: 6243: 6239: 6238: 6233: 6228: 6225: 6224:0-387-94327-7 6221: 6217: 6213: 6210: 6207: 6203: 6200: 6195: 6193:1-4196-2722-8 6189: 6186:. Booksurge. 6185: 6184: 6179: 6178:Brown, Ronald 6175: 6172: 6168: 6165: 6162: 6161:0-387-97926-3 6158: 6154: 6150: 6147: 6143: 6141:0-387-90839-0 6137: 6133: 6129: 6124: 6123: 6119: 6110: 6106: 6102: 6098: 6094: 6090: 6087:(1): 91–119. 6086: 6082: 6081: 6073: 6069: 6065: 6059: 6056: 6051: 6047: 6043: 6039: 6035: 6031: 6027: 6023: 6020:topologies". 6005: 6001: 5978: 5974: 5962: 5959: 5954: 5948: 5944: 5937: 5934: 5930: 5925: 5922: 5918: 5913: 5910: 5906: 5901: 5898: 5894: 5889: 5886: 5882: 5880: 5867: 5865:9783110989854 5861: 5857: 5856: 5851: 5845: 5842: 5837: 5829: 5825: 5824: 5818: 5811: 5808: 5802: 5799: 5795: 5790: 5788: 5784: 5780: 5775: 5772: 5767: 5763: 5759: 5757:0-19-853155-9 5753: 5749: 5748: 5740: 5737: 5733: 5732:Schubert 1968 5728: 5725: 5718: 5713: 5710: 5704: 5701: 5695: 5692: 5689: 5686: 5683: 5680: 5677: 5676:Hilbert space 5674: 5671: 5668: 5666: 5663: 5660: 5657: 5654: 5653:Compact space 5651: 5648: 5645: 5644: 5640: 5638: 5636: 5632: 5628: 5624: 5623:connectedness 5620: 5616: 5610: 5602: 5600: 5587: 5582: 5578: 5555: 5551: 5543: 5539: 5535: 5533: 5529: 5525: 5521: 5516: 5514: 5510: 5507:Many sets of 5505: 5492: 5489: 5466: 5437: 5429: 5401: 5396: 5380: 5360: 5354: 5348: 5345: 5342: 5336: 5330: 5327: 5307: 5304: 5301: 5293: 5291: 5287: 5282: 5279: 5276: 5272: 5268: 5267: 5263:: A space is 5262: 5259: 5258: 5254: 5252: 5250: 5246: 5245:solution sets 5230: 5225: 5196: 5181: 5177: 5173: 5168: 5166: 5161: 5159: 5155: 5151: 5147: 5142: 5134: 5132: 5116: 5101: 5085: 5072: 5054: 5039: 5021: 5007: 5002: 4998: 4972: 4956: 4942: 4940: 4936: 4932: 4927: 4925: 4919: 4912:Metric spaces 4911: 4909: 4893: 4889: 4868: 4848: 4828: 4825: 4805: 4783: 4779: 4775: 4772: 4769: 4764: 4760: 4739: 4719: 4712: 4709: 4705: 4704:Fell topology 4700: 4687: 4682: 4678: 4655: 4651: 4630: 4627: 4605: 4601: 4597: 4594: 4591: 4586: 4582: 4561: 4553: 4537: 4534: 4526: 4521: 4519: 4503: 4483: 4480: 4472: 4456: 4436: 4428: 4412: 4409: 4401: 4385: 4365: 4357: 4354: 4338: 4332: 4329: 4326: 4306: 4286: 4278: 4273: 4270: 4266: 4262: 4258: 4247: 4242: 4238: 4237: 4236:Fell topology 4232: 4231: 4226: 4221: 4212: 4211: 4205: 4203: 4201: 4197: 4192: 4190: 4186: 4182: 4178: 4173: 4160: 4157: 4137: 4117: 4094: 4091: 4088: 4065: 4059: 4056: 4053: 4031: 4025: 4022: 4019: 4008: 3989: 3986: 3983: 3977: 3974: 3966: 3950: 3941: 3904: 3898: 3895: 3892: 3881: 3876: 3874: 3869: 3867: 3860: 3855: 3853: 3849: 3844: 3842: 3838: 3834: 3828: 3820: 3818: 3816: 3812: 3808: 3804: 3800: 3799:homeomorphism 3797: 3793: 3789: 3785: 3781: 3777: 3773: 3768: 3764: 3762: 3758: 3754: 3753:homeomorphism 3750: 3749:inverse image 3734: 3714: 3711: 3708: 3702: 3696: 3676: 3656: 3633: 3627: 3607: 3587: 3584: 3581: 3574:if for every 3573: 3572: 3555: 3549: 3546: 3543: 3536: 3530: 3522: 3520: 3507: 3504: 3484: 3464: 3456: 3440: 3437: 3417: 3409: 3393: 3390: 3369: 3365: 3362: 3359: 3356: 3351: 3347: 3342: 3338: 3335: 3327: 3311: 3302: 3298: 3294: 3290: 3286: 3271: 3266: 3262: 3251: 3235: 3231: 3210: 3205: 3201: 3190: 3174: 3170: 3149: 3144: 3140: 3117: 3113: 3102: 3094: 3092: 3090: 3074: 3066: 3062: 3057: 3044: 3041: 3033: 3029: 3025: 3021: 3016: 3009: 3007: 2993: 2973: 2953: 2950: 2930: 2910: 2898: 2895: 2880: 2872: 2871: 2870: 2868: 2867: 2862: 2854: 2838: 2835: 2815: 2799: 2763: 2743: 2735: 2732: 2724: 2721: 2720: 2700: 2697: 2694: 2671: 2668: 2645: 2636: 2633: 2613: 2610: 2602: 2586: 2578: 2562: 2556: 2553: 2550: 2547: 2544: 2541: 2538: 2532: 2529: 2521: 2507: 2504: 2484: 2461: 2458: 2452: 2449: 2446: 2443: 2440: 2434: 2428: 2425: 2422: 2416: 2410: 2407: 2404: 2398: 2392: 2386: 2377: 2374: 2354: 2348: 2345: 2342: 2339: 2336: 2333: 2330: 2324: 2321: 2313: 2299: 2296: 2276: 2253: 2250: 2241: 2232: 2229: 2226: 2223: 2220: 2217: 2214: 2208: 2196: 2193: 2186: 2170: 2160: 2158: 2142: 2136: 2133: 2130: 2127: 2124: 2121: 2118: 2112: 2109: 2101: 2100: 2081: 2055: 2052: 2049: 2023: 2020: 2017: 1991: 1988: 1985: 1959: 1933: 1910: 1904: 1901: 1898: 1895: 1892: 1869: 1860: 1853: 1851: 1837: 1831: 1824: 1805: 1802: 1799: 1786: 1772: 1769: 1766: 1757: 1744: 1741: 1733: 1717: 1694: 1691: 1671: 1663: 1649: 1646: 1626: 1618: 1614: 1600: 1597: 1577: 1569: 1565: 1564: 1563: 1561: 1553: 1537: 1526: 1522: 1514: 1512: 1499: 1496: 1493: 1490: 1470: 1450: 1430: 1410: 1389: 1386: 1366: 1358: 1342: 1322: 1313: 1300: 1297: 1277: 1268:neighbourhood 1267: 1231: 1211: 1197: 1184: 1181: 1157: 1154: 1134: 1114: 1094: 1074: 1054: 1046: 1032: 1029: 1009: 1001: 997: 983: 980: 960: 957: 954: 946: 930: 927: 907: 887: 884: 864: 844: 836: 797: 777: 774: 771: 768: 745: 732: 729: 709: 689: 681: 680: 679: 677: 637: 629: 625: 584: 576: 575:(or, simply, 538: 528: 511: 481: 478: 455: 425: 405: 397: 367: 353: 333: 325: 317: 315: 312: 309: 306: 303: 301: 297: 293: 287: 279: 277: 275: 271: 267: 262: 258: 257:Metric spaces 254: 249: 247: 243: 239: 235: 231: 227: 223: 218: 216: 211: 207: 203: 198: 196: 192: 188: 185:(1750–1840), 184: 180: 176: 172: 156: 153: 150: 147: 144: 141: 138: 131: 127: 124:Around 1735, 119: 117: 115: 111: 106: 104: 100: 99:metric spaces 96: 92: 91:connectedness 88: 84: 80: 75: 73: 69: 65: 61: 57: 53: 49: 45: 41: 37: 33: 19: 6797:Publications 6662:Chern number 6652:Betti number 6551: 6535: / 6526:Key concepts 6474:Differential 6395: 6365: 6346:Set Topology 6345: 6327: 6303: 6287: 6272: 6254: 6246: 6236: 6215: 6205: 6202:ÄŚech, Eduard 6182: 6170: 6152: 6134:. Springer. 6127: 6120:Bibliography 6084: 6078: 6064:Culler, Marc 6058: 6025: 6021: 5961: 5942: 5936: 5924: 5912: 5900: 5888: 5878: 5876: 5869:. Retrieved 5854: 5844: 5821: 5810: 5801: 5774: 5746: 5739: 5727: 5612: 5536: 5520:linear graph 5517: 5506: 5405: 5289: 5285: 5280: 5264: 5260: 5169: 5162: 5158:local fields 5138: 5037: 4971:real numbers 4943: 4939:vector space 4931:metric space 4928: 4921: 4918:Metric space 4711:Polish space 4703: 4701: 4524: 4522: 4274: 4254: 4245: 4234: 4228: 4193: 4174: 3942: 3877: 3870: 3856: 3845: 3830: 3779: 3769: 3765:homeomorphic 3569: 3532: 3303: 3104: 3058: 3024:fixed points 3017: 3013: 2902: 2864: 2858: 2717: 2716:is called a 2163:topology on 1758: 1731: 1709: 1559: 1520: 1518: 1356: 1314: 1198: 1172: 1000:intersection 943:I.e., every 675: 674:is called a 622:is called a 321: 291: 289: 250: 219: 215:homeomorphic 200:Yet, "until 199: 194: 175:planar graph 123: 107: 76: 35: 29: 6760:Wikiversity 6677:Key results 6240:. Springer. 5627:compactness 5538:Outer space 5251:equations. 5165:local field 5098:the set of 4969:the set of 4246:(June 2024) 2893:are closed. 2866:closed sets 2367:the family 1684:belongs to 1639:belongs to 418:(point) in 280:Definitions 222:Felix Klein 32:mathematics 6812:Categories 6606:CW complex 6547:Continuity 6537:Closed set 6496:cohomology 6355:0486404560 6232:Xu, Dianna 6206:Point Sets 5905:Brown 2006 5893:Brown 2006 5838:required.) 5779:Gauss 1827 5542:free group 5249:polynomial 4550:named for 4449:for which 4353:surjective 4269:projection 4187:and every 3848:finite set 3825:See also: 3803:invariants 3776:categories 3689:such that 3571:continuous 2798:itself is 2161:indiscrete 1823:complement 1483:such that 1127:such that 193:published 87:continuity 6785:geometric 6780:algebraic 6631:Cobordism 6567:Hausdorff 6562:connected 6479:Geometric 6469:Continuum 6459:Algebraic 6402:EMS Press 6109:122869546 6028:: 77–81. 5871:20 August 5719:Citations 5470:Γ 5467:∪ 5461:∅ 5430:on a set 5414:Γ 5349:⁡ 5343:⊆ 5331:⁡ 5305:≤ 5277:theorem). 4773:… 4595:… 4336:→ 4158:γ 4138:β 4118:α 4095:γ 4089:α 4060:β 4026:β 4020:α 3990:γ 3975:γ 3951:γ 3792:morphisms 3757:bijection 3709:⊆ 3585:∈ 3553:→ 3406:then the 3363:∈ 3360:α 3352:α 3348:τ 3263:τ 3232:τ 3202:τ 3171:τ 3141:τ 3114:τ 3032:power set 2974:τ 2931:τ 2836:τ 2764:τ 2701:τ 2640:℘ 2634:τ 2601:power set 2384:∅ 2375:τ 2248:∅ 2194:τ 1870:τ 1835:∖ 1806:τ 1770:⊆ 1759:A subset 1718:τ 1692:τ 1672:τ 1647:τ 1627:τ 1598:τ 1568:empty set 1560:open sets 1558:, called 1538:τ 1494:∈ 958:∈ 772:∈ 733:∈ 305:open sets 266:‹See Tfd› 217:or not." 183:L'Huilier 142:− 103:manifolds 72:open sets 44:closeness 42:in which 6750:Wikibook 6728:Category 6616:Manifold 6584:Homotopy 6542:Interior 6533:Open set 6491:Homology 6440:Topology 6304:Topology 6273:Topology 6234:(2013). 6180:(2006). 6070:(1986). 5943:Topology 5641:See also 5528:vertices 5275:Hochster 5266:spectral 5261:Spectral 5139:For any 4496:The map 4356:function 4177:manifold 3815:K-theory 3535:function 3453:and the 3324:forms a 3295:stronger 3065:sequence 3028:operator 1732:topology 1521:topology 945:superset 761:), then 396:function 292:topology 224:in his " 60:topology 48:distance 6775:general 6577:uniform 6557:compact 6508:Digital 6404:, 2001 6089:Bibcode 6050:0244927 6042:2037491 5766:1679102 5734:, p. 13 4752:-tuple 4574:-tuple 4241:Discuss 4185:simplex 3788:objects 3761:inverse 3291:smaller 3252:coarser 3030:on the 2599:is the 2183:is the 2157:trivial 1821:if its 1552:subsets 722:(i.e., 626:if the 202:Riemann 130:formula 120:History 6770:Topics 6572:metric 6447:Fields 6373:  6352:  6336:  6310:  6294:  6279:  6261:  6222:  6190:  6159:  6138:  6107:  6048:  6040:  5949:  5862:  5764:  5754:  5524:graphs 5428:filter 5373:where 5182:. 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Let 270:German 210:Jordan 206:Möbius 179:Cauchy 89:, and 83:limits 68:axioms 56:points 6552:Space 6105:S2CID 6075:(PDF) 6038:JSTOR 5832: 5615:up to 5540:of a 5532:edges 5526:with 5450:then 5426:is a 5071:balls 4351:is a 4225:split 3801:) by 3796:up to 3755:is a 3328:: if 3254:than 3193:than 3191:finer 1617:union 1523:on a 900:then 650:with 394:be a 6371:ISBN 6350:ISBN 6334:ISBN 6322:and 6308:ISBN 6292:ISBN 6277:ISBN 6259:ISBN 6220:ISBN 6188:ISBN 6157:ISBN 6136:ISBN 5947:ISBN 5873:2022 5860:ISBN 5762:OCLC 5752:ISBN 5530:and 5288:(or 5170:The 5163:Any 5156:and 5001:base 4702:The 4523:The 4233:and 4194:The 4130:and 4078:and 3455:join 3408:meet 3297:and 3289:and 3223:and 2575:the 2155:the 2039:and 1949:and 1862:Let 1570:and 1566:The 1357:open 998:The 240:and 208:and 101:and 34:, a 6097:doi 6030:doi 5881:, . 5511:in 5406:If 5211:or 5040:on 4239:. 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Index

Vietoris topology
mathematics
geometrical space
closeness
distance
set
points
topology
neighbourhoods
axioms
open sets
mathematical space
limits
continuity
connectedness
Euclidean spaces
metric spaces
manifolds
point-set topology
general topology
Leonhard Euler
formula
convex polyhedron
planar graph
Cauchy
L'Huilier
boosted the study
Carl Friedrich Gauss
Riemann
Möbius

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