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Topological property

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Simon Moulieras, Maciej Lewenstein and Graciana Puentes, Entanglement engineering and topological protection by discrete-time quantum walks, Journal of Physics B: Atomic, Molecular and Optical Physics 46 (10), 104005 (2013).
2186:. A space is said to be κ-resolvable (respectively: almost κ-resolvable) if it contains κ dense sets that are pairwise disjoint (respectively: almost disjoint over the ideal of nowhere dense subsets). If the space is not 2361: 2759: 2817: 372: 227: 502: 1548: 291: 143: 2700: 2034: 1425: 444: 320: 172: 2146:
if it is zero-dimensional, compact and Hausdorff (equivalently, totally disconnected, compact and Hausdorff). These are precisely the spaces that are homeomorphic to the
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if every point has a local base consisting of compact neighbourhoods. Slightly different definitions are also used. Locally compact Hausdorff spaces are always Tychonoff.
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spaces where every open cover has finite subcover. Compact spaces are always Lindelöf and paracompact. Compact Hausdorff spaces are therefore normal.
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if every point has a local base consisting of path-connected sets. A locally path-connected space is connected if and only if it is path-connected.
1610:. Semi-local simple connectivity, a strictly weaker condition than local simple connectivity, is a necessary condition for the existence of a 1820:. Metrizable spaces are always Hausdorff and paracompact (and hence normal and Tychonoff), and first-countable. Moreover, a topological space 51:
of topological spaces which is closed under homeomorphisms. That is, a property of spaces is a topological property if whenever a space
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if every open set is closed (hence clopen). The almost discrete spaces are precisely the finitely generated zero-dimensional spaces.
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possesses that property. Informally, a topological property is a property of the space that can be expressed using
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if it is not the union of a pair of disjoint non-empty open sets. Equivalently, a space is connected if the only
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if every open cover has an open locally finite refinement. Paracompact Hausdorff spaces are normal.
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base for its topology. Second-countable spaces are always separable, first-countable and Lindelöf.
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are open, or equivalently if arbitrary unions of closed sets are closed. These are precisely the
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is not the (possibly nondisjoint) union of two smaller closed non-empty subsets, then there is a
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itself. Non-empty ultra-connected compact spaces have a largest proper open subset called a
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if no two non-empty closed sets are disjoint. Every ultraconnected space is path-connected.
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homeomorphic, it is sufficient to find a topological property which is not shared by them.
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if the only open sets are the empty set and itself. Such a space is said to have the
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if no two non-empty open sets are disjoint. Every hyperconnected space is connected.
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Intuitively speaking, this means that the space looks the same at every point. All
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if any two disjoint closed sets have disjoint neighbourhoods. Normal spaces admit
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Some of these terms are defined differently in older mathematical literature; see
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is not topological, it is sufficient to find two homeomorphic topological spaces
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is a Baire space if the intersection of countably many dense open sets is dense.
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is homotopic to a constant map. Contractible spaces are always simply connected.
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if it has a base of clopen sets. These are precisely the spaces with a small
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A common problem in topology is to decide whether two topological spaces are
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if all of its points are completely isolated, i.e. if any subset is open.
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space. (A completely regular space is Hausdorff if and only if it is T
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https://iopscience.iop.org/article/10.1088/0953-4075/46/10/104005/pdf
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if every continuous real-valued function on the space is bounded.
1073:. Completely normal Hausdorff spaces are always normal Hausdorff. 2537:, etc, which are not topological properties. To show a property 2500:
is said to be strongly discrete if every non-isolated point of
1069:. A completely normal space is Hausdorff if and only if it is T 2928: – Association of cohomology classes to principal bundles 2922: – Association of cohomology classes to principal bundles 701:
in the space, there is at least either an open set containing
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Juhász, István; Soukup, Lajos; Szentmiklóssy, Zoltán (2008).
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if every point has a local base consisting of connected sets.
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space. (A regular space is Hausdorff if and only if it is T
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if every two distinct points have disjoint neighbourhoods. T
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may be separated by pairwise disjoint neighborhoods. Space
2985: – List of concrete topologies and topological spaces 2754:{\displaystyle Y=(-{\tfrac {\pi }{2}},{\tfrac {\pi }{2}})} 1087:. A perfectly normal space must also be completely normal. 1933:
if it is metrizable with a separable and complete metric.
3093:. Reading, Mass.: Addison-Wesley Pub. Co. p. 369. 2930:
Pages displaying short descriptions of redirect targets
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if it has no connected subset with more than one point.
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of the topology (the set of open subsets) of the space
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Cardinal function § Cardinal functions in topology
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is said to be metrizable if there exists a metric for
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if it is the union of countably many compact subsets.
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if every countable open cover has a finite subcover.
1038:. A normal space is Hausdorff if and only if it is T 55:
possesses that property every space homeomorphic to
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Alternatively, a topological property is a 2943: – Topological invariant in mathematics 2666:For example, the metric space properties of 2347: 2306: 1978:if every subset is open or closed (or both). 491: 476: 433: 427: 2991: – Concept in mathematical knot theory 2096:if arbitrary intersections of open sets in 846:if every two distinct points have disjoint 1497:. Arc-connected spaces are path-connected. 1139: 3050: 3040: 2688: 2533:There are many examples of properties of 2440:is strongly discrete subset of the space 3107: 3086: 616:, the least cardinality of a subset of 3144: 3023:"Resolvability and monotone normality" 1787:. In an ultra-connected compact space 1111:, if it is both perfectly normal and T 804:is the only point with this property. 734:if for every pair of distinct points 693:if for every pair of distinct points 405: 70:or not. To prove that two spaces are 2866: 2674:are not topological properties. Let 1083:if any two disjoint closed sets are 497:{\displaystyle \vert \tau (X)\vert } 78:Properties of topological properties 2839:is complete but not bounded, while 758:if all its singletons are closed. T 13: 2392:is called dispersion character of 2370: 2288: 2259: 1576:has a local base of neighborhoods 1543:{\displaystyle f\colon S^{1}\to X} 342: 286:{\displaystyle (X,{\mathcal {T}})} 275: 197: 138:{\displaystyle (X,{\mathcal {T}})} 127: 14: 3168: 2331: 2252:is maximally resolvable if it is 1699:. Some authors call these spaces 1085:precisely separated by a function 878:if every two distinct points are 257:, if for every topological space 109:, if for every topological space 3152:Properties of topological spaces 2871: 1943: 1803: 1232: 776:if every irreducible closed set 673:history of the separation axioms 16:Mathematical property of a space 1901:is identical with the topology 3014: 2886:format but may read better as 2803: 2748: 2715: 2695:{\displaystyle X=\mathbb {R} } 2524:of some strongly discrete set. 2379: 2373: 2318: 2310: 2297: 2291: 2268: 2262: 2206:-resolvable then it is called 2106:category of topological spaces 2052: 2046: 2029:{\displaystyle f\colon X\to X} 2020: 1888: 1882: 1872:such that the metric topology 1839: 1827: 1791:every open cover must contain 1678: 1534: 1478: 1472: 1443: 1437: 1411: 1408: 1396: 603: 597: 545: 539: 488: 482: 349: 280: 264: 204: 132: 116: 1: 3079: 3028:Israel Journal of Mathematics 2949: – Mathematical property 2859:is bounded but not complete. 1592:semi-locally simply connected 1584:Semi-locally simply connected 1420:{\displaystyle f\colon \to X} 1249:are the empty set and itself. 1056:have disjoint neighbourhoods. 912:have disjoint neighbourhoods. 660: 558:, the least cardinality of a 439:{\displaystyle \vert X\vert } 401:Common topological properties 315:{\displaystyle S\subseteq X,} 167:{\displaystyle S\subseteq X,} 3007: 990:Completely regular Hausdorff 709:, or an open set containing 7: 2862: 1974:. A topological space is a 1816:if it is homeomorphic to a 1067:Completely normal Hausdorff 780:has a unique generic point 10: 3173: 2995:Topological quantum number 2529:Non-topological properties 2385:{\displaystyle \Delta (X)} 2274:{\displaystyle \Delta (X)} 1757:if every open cover has a 1200:if every open cover has a 1143: 1109:perfectly normal Hausdorff 1098:Perfectly normal Hausdorff 792:such that the closure of { 664: 409: 3087:Willard, Stephen (1970). 3052:10.1007/s11856-008-1017-y 2004:there is a homeomorphism 1964:in itself. Equivalently, 1580:that is simply connected. 1307:, i.e., a continuous map 1129:Number of isolated points 1003:is a completely regular T 2780:{\displaystyle X\cong Y} 2576:{\displaystyle X\cong Y} 1703:and reserve compact for 1566:locally simply connected 1558:Locally simply connected 1355:if for every two points 1283:if for every two points 937:, so the terminology is 2895:converting this article 2219:{\displaystyle \kappa } 2199:{\displaystyle \kappa } 2177:{\displaystyle \kappa } 2067:{\displaystyle f(x)=y.} 1982:Topological Homogeneity 1140:Countability conditions 1135:of a topological space. 973:separated by a function 880:separated by a function 2926:Characteristic numbers 2853: 2833: 2813: 2787:via the homeomorphism 2781: 2755: 2696: 2657: 2637: 2617: 2597: 2577: 2551: 2514: 2494: 2474: 2454: 2434: 2409: 2386: 2357: 2275: 2246: 2220: 2200: 2178: 2068: 2030: 1918: 1895: 1866: 1846: 1785:Ultraconnected compact 1544: 1491: 1490:{\displaystyle p(1)=y} 1456: 1455:{\displaystyle p(0)=x} 1421: 1339:locally path-connected 1335:Locally path-connected 1217:if it is the union of 784:. In other words, if 650: 630: 610: 576: 552: 518: 498: 460: 440: 391: 368: 316: 287: 246: 223: 168: 139: 96: 2854: 2834: 2814: 2782: 2756: 2697: 2658: 2638: 2618: 2598: 2578: 2552: 2515: 2495: 2475: 2455: 2435: 2410: 2387: 2358: 2276: 2247: 2221: 2201: 2179: 2069: 2031: 1919: 1896: 1867: 1847: 1845:{\displaystyle (X,T)} 1545: 1492: 1457: 1422: 1172:if every point has a 1146:Axiom of countability 651: 631: 611: 577: 560:basis of the topology 553: 519: 499: 461: 441: 392: 369: 317: 288: 247: 224: 169: 140: 97: 33:topological invariant 23:and related areas of 2947:Fixed-point property 2941:Euler characteristic 2920:Characteristic class 2843: 2823: 2791: 2765: 2706: 2678: 2647: 2627: 2607: 2587: 2561: 2541: 2504: 2484: 2464: 2444: 2424: 2396: 2367: 2285: 2256: 2236: 2230:Maximally resolvable 2210: 2190: 2168: 2159:Reidemeister torsion 2108:and continuous maps. 2040: 2008: 1929:. A space is called 1905: 1894:{\displaystyle T(d)} 1876: 1856: 1824: 1715:sequentially compact 1711:Sequentially compact 1515: 1466: 1431: 1387: 1311::  →  1267:totally disconnected 1263:Totally disconnected 955:is a closed set and 929:if it is a regular T 896:is a closed set and 869:completely Hausdorff 640: 620: 609:{\displaystyle d(X)} 591: 566: 551:{\displaystyle w(X)} 533: 508: 473: 450: 424: 378: 326: 297: 261: 233: 181: 149: 113: 86: 29:topological property 2281:-resolvable, where 2120:inductive dimension 1988:is (topologically) 1606:is contractible in 1023:partitions of unity 854:spaces are always T 825:spaces are always T 762:spaces are always T 35:is a property of a 2983:List of topologies 2897:, if appropriate. 2849: 2829: 2809: 2777: 2751: 2746: 2731: 2692: 2653: 2633: 2613: 2593: 2573: 2547: 2522:accumulation point 2510: 2490: 2470: 2450: 2430: 2408:{\displaystyle X.} 2405: 2382: 2353: 2345: 2271: 2242: 2216: 2196: 2174: 2102:finitely generated 2082:Finitely generated 2076:topological groups 2064: 2026: 1937:Locally metrizable 1917:{\displaystyle T.} 1914: 1891: 1862: 1842: 1554:to a constant map. 1540: 1487: 1452: 1417: 1367:, there is an arc 1295:, there is a path 959:is a point not in 949:completely regular 945:Completely regular 900:is a point not in 646: 626: 606: 572: 548: 514: 494: 456: 436: 406:Cardinal functions 390:{\displaystyle P.} 387: 364: 312: 293:and closed subset 283: 245:{\displaystyle P.} 242: 219: 164: 135: 92: 3109:Munkres, James R. 2989:Quantum invariant 2916: 2915: 2852:{\displaystyle Y} 2832:{\displaystyle X} 2745: 2730: 2656:{\displaystyle P} 2636:{\displaystyle Y} 2616:{\displaystyle P} 2596:{\displaystyle X} 2550:{\displaystyle P} 2513:{\displaystyle X} 2493:{\displaystyle X} 2473:{\displaystyle D} 2460:if the points in 2453:{\displaystyle X} 2433:{\displaystyle D} 2418:Strongly discrete 2344: 2245:{\displaystyle X} 1865:{\displaystyle X} 1725:countably compact 1721:Countably compact 1257:locally connected 1253:Locally connected 1050:completely normal 1046:Completely normal 927:regular Hausdorff 923:Regular Hausdorff 850:neighbourhoods. T 750:. (Compare with T 649:{\displaystyle X} 636:whose closure is 629:{\displaystyle X} 575:{\displaystyle X} 517:{\displaystyle X} 459:{\displaystyle X} 255:Weakly hereditary 95:{\displaystyle P} 37:topological space 3164: 3130: 3104: 3090:General topology 3073: 3072: 3054: 3044: 3018: 2966:Cohomotopy group 2931: 2911: 2908: 2902: 2893:You can help by 2875: 2874: 2867: 2858: 2856: 2855: 2850: 2838: 2836: 2835: 2830: 2818: 2816: 2815: 2810: 2786: 2784: 2783: 2778: 2760: 2758: 2757: 2752: 2747: 2738: 2732: 2723: 2701: 2699: 2698: 2693: 2691: 2662: 2660: 2659: 2654: 2642: 2640: 2639: 2634: 2622: 2620: 2619: 2614: 2602: 2600: 2599: 2594: 2582: 2580: 2579: 2574: 2556: 2554: 2553: 2548: 2519: 2517: 2516: 2511: 2499: 2497: 2496: 2491: 2479: 2477: 2476: 2471: 2459: 2457: 2456: 2451: 2439: 2437: 2436: 2431: 2414: 2412: 2411: 2406: 2391: 2389: 2388: 2383: 2362: 2360: 2359: 2354: 2346: 2342: 2321: 2313: 2280: 2278: 2277: 2272: 2251: 2249: 2248: 2243: 2225: 2223: 2222: 2217: 2205: 2203: 2202: 2197: 2183: 2181: 2180: 2175: 2152:Boolean algebras 2116:zero-dimensional 2112:Zero-dimensional 2078:are homogeneous. 2073: 2071: 2070: 2065: 2035: 2033: 2032: 2027: 1923: 1921: 1920: 1915: 1900: 1898: 1897: 1892: 1871: 1869: 1868: 1863: 1851: 1849: 1848: 1843: 1672:trivial topology 1549: 1547: 1546: 1541: 1533: 1532: 1509:simply connected 1501:Simply connected 1496: 1494: 1493: 1488: 1461: 1459: 1458: 1453: 1426: 1424: 1423: 1418: 1184:second-countable 1180:Second-countable 1131:. The number of 1081:perfectly normal 1077:Perfectly normal 1036:Normal Hausdorff 667:Separation axiom 655: 653: 652: 647: 635: 633: 632: 627: 615: 613: 612: 607: 581: 579: 578: 573: 557: 555: 554: 549: 523: 521: 520: 515: 503: 501: 500: 495: 469:The cardinality 465: 463: 462: 457: 445: 443: 442: 437: 396: 394: 393: 388: 373: 371: 370: 365: 363: 359: 358: 357: 352: 346: 345: 321: 319: 318: 313: 292: 290: 289: 284: 279: 278: 251: 249: 248: 243: 228: 226: 225: 220: 218: 214: 213: 212: 207: 201: 200: 173: 171: 170: 165: 144: 142: 141: 136: 131: 130: 101: 99: 98: 93: 3172: 3171: 3167: 3166: 3165: 3163: 3162: 3161: 3142: 3141: 3133: 3127: 3101: 3082: 3077: 3076: 3019: 3015: 3010: 2929: 2912: 2906: 2903: 2892: 2876: 2872: 2865: 2844: 2841: 2840: 2824: 2821: 2820: 2792: 2789: 2788: 2766: 2763: 2762: 2736: 2721: 2707: 2704: 2703: 2687: 2679: 2676: 2675: 2648: 2645: 2644: 2628: 2625: 2624: 2608: 2605: 2604: 2588: 2585: 2584: 2562: 2559: 2558: 2542: 2539: 2538: 2531: 2505: 2502: 2501: 2485: 2482: 2481: 2465: 2462: 2461: 2445: 2442: 2441: 2425: 2422: 2421: 2397: 2394: 2393: 2368: 2365: 2364: 2340: 2317: 2309: 2286: 2283: 2282: 2257: 2254: 2253: 2237: 2234: 2233: 2211: 2208: 2207: 2191: 2188: 2187: 2169: 2166: 2165: 2134:almost discrete 2130:Almost discrete 2104:members of the 2041: 2038: 2037: 2009: 2006: 2005: 1946: 1906: 1903: 1902: 1877: 1874: 1873: 1857: 1854: 1853: 1825: 1822: 1821: 1806: 1779:locally compact 1775:Locally compact 1681: 1612:universal cover 1568:if every point 1528: 1524: 1516: 1513: 1512: 1467: 1464: 1463: 1432: 1429: 1428: 1388: 1385: 1384: 1383:continuous map 1235: 1170:first-countable 1166:First-countable 1148: 1142: 1133:isolated points 1114: 1105: 1094: 1072: 1063: 1041: 1032: 1010: 1006: 1001:Tychonoff space 997: 982: 936: 932: 919: 876: 865: 857: 853: 836: 828: 824: 811: 765: 761: 757: 753: 724: 683: 669: 663: 641: 638: 637: 621: 618: 617: 592: 589: 588: 567: 564: 563: 534: 531: 530: 509: 506: 505: 474: 471: 470: 451: 448: 447: 425: 422: 421: 414: 408: 403: 379: 376: 375: 353: 348: 347: 341: 340: 333: 329: 327: 324: 323: 298: 295: 294: 274: 273: 262: 259: 258: 234: 231: 230: 208: 203: 202: 196: 195: 188: 184: 182: 179: 178: 150: 147: 146: 126: 125: 114: 111: 110: 87: 84: 83: 80: 17: 12: 11: 5: 3170: 3160: 3159: 3157:Homeomorphisms 3154: 3132: 3131: 3125: 3105: 3099: 3083: 3081: 3078: 3075: 3074: 3012: 3011: 3009: 3006: 3005: 3004: 3001:Winding number 2998: 2992: 2986: 2980: 2977:Linking number 2974: 2971:Knot invariant 2968: 2962:Homotopy group 2959: 2950: 2944: 2938: 2932: 2923: 2914: 2913: 2879: 2877: 2870: 2864: 2861: 2848: 2828: 2808: 2805: 2802: 2799: 2796: 2776: 2773: 2770: 2750: 2744: 2741: 2735: 2729: 2726: 2720: 2717: 2714: 2711: 2690: 2686: 2683: 2652: 2643:does not have 2632: 2612: 2592: 2572: 2569: 2566: 2546: 2530: 2527: 2526: 2525: 2509: 2489: 2469: 2449: 2429: 2415: 2404: 2401: 2381: 2378: 2375: 2372: 2352: 2349: 2339: 2336: 2333: 2330: 2327: 2324: 2320: 2316: 2312: 2308: 2305: 2302: 2299: 2296: 2293: 2290: 2270: 2267: 2264: 2261: 2241: 2227: 2226:-irresolvable. 2215: 2195: 2173: 2162: 2155: 2137: 2127: 2109: 2079: 2063: 2060: 2057: 2054: 2051: 2048: 2045: 2025: 2022: 2019: 2016: 2013: 1979: 1969: 1945: 1942: 1941: 1940: 1934: 1924: 1913: 1910: 1890: 1887: 1884: 1881: 1861: 1841: 1838: 1835: 1832: 1829: 1805: 1802: 1801: 1800: 1782: 1772: 1762: 1748: 1738: 1728: 1718: 1708: 1680: 1677: 1676: 1675: 1657: 1654:ultraconnected 1650:Ultraconnected 1647: 1644:hyperconnected 1640:Hyperconnected 1637: 1615: 1581: 1555: 1539: 1536: 1531: 1527: 1523: 1520: 1498: 1486: 1483: 1480: 1477: 1474: 1471: 1451: 1448: 1445: 1442: 1439: 1436: 1416: 1413: 1410: 1407: 1404: 1401: 1398: 1395: 1392: 1342: 1332: 1281:path-connected 1273:Path-connected 1270: 1260: 1250: 1234: 1231: 1230: 1229: 1205: 1191: 1177: 1163: 1141: 1138: 1137: 1136: 1126: 1119:Discrete space 1116: 1112: 1103: 1092: 1088: 1074: 1070: 1061: 1057: 1054:separated sets 1043: 1039: 1030: 1026: 1012: 1008: 1004: 995: 980: 976: 942: 934: 930: 917: 913: 883: 874: 871:. A space is 863: 859: 855: 851: 834: 830: 826: 822: 809: 805: 767: 763: 759: 755: 751: 722: 718: 681: 665:Main article: 662: 659: 658: 657: 645: 625: 605: 602: 599: 596: 583: 571: 547: 544: 541: 538: 525: 513: 493: 490: 487: 484: 481: 478: 467: 455: 435: 432: 429: 410:Main article: 407: 404: 402: 399: 398: 397: 386: 383: 362: 356: 351: 344: 339: 336: 332: 311: 308: 305: 302: 282: 277: 272: 269: 266: 252: 241: 238: 217: 211: 206: 199: 194: 191: 187: 163: 160: 157: 154: 134: 129: 124: 121: 118: 91: 79: 76: 45:homeomorphisms 15: 9: 6: 4: 3: 2: 3169: 3158: 3155: 3153: 3150: 3149: 3147: 3140: 3139: 3128: 3126:0-13-181629-2 3122: 3118: 3117:Prentice-Hall 3114: 3110: 3106: 3102: 3100:9780486434797 3096: 3092: 3091: 3085: 3084: 3070: 3066: 3062: 3058: 3053: 3048: 3043: 3038: 3034: 3030: 3029: 3024: 3017: 3013: 3002: 2999: 2996: 2993: 2990: 2987: 2984: 2981: 2978: 2975: 2972: 2969: 2967: 2963: 2960: 2958: 2954: 2951: 2948: 2945: 2942: 2939: 2936: 2933: 2927: 2924: 2921: 2918: 2917: 2910: 2901:is available. 2900: 2896: 2890: 2889: 2885: 2880:This article 2878: 2869: 2868: 2860: 2846: 2826: 2806: 2800: 2797: 2794: 2774: 2771: 2768: 2742: 2739: 2733: 2727: 2724: 2718: 2712: 2709: 2684: 2681: 2673: 2669: 2664: 2650: 2630: 2610: 2590: 2570: 2567: 2564: 2544: 2536: 2535:metric spaces 2523: 2507: 2487: 2467: 2447: 2427: 2419: 2416: 2402: 2399: 2376: 2350: 2343: is open 2337: 2334: 2328: 2325: 2322: 2314: 2300: 2294: 2265: 2239: 2231: 2228: 2213: 2193: 2185: 2171: 2163: 2161: 2160: 2156: 2153: 2149: 2145: 2142:. A space is 2141: 2138: 2135: 2132:. A space is 2131: 2128: 2125: 2121: 2117: 2114:. A space is 2113: 2110: 2107: 2103: 2099: 2095: 2091: 2087: 2083: 2080: 2077: 2061: 2058: 2055: 2049: 2043: 2023: 2017: 2014: 2011: 2003: 1999: 1995: 1992:if for every 1991: 1987: 1983: 1980: 1977: 1973: 1970: 1967: 1963: 1960:if it is not 1959: 1955: 1951: 1948: 1947: 1944:Miscellaneous 1938: 1935: 1932: 1928: 1925: 1911: 1908: 1885: 1879: 1859: 1836: 1833: 1830: 1819: 1815: 1812:. A space is 1811: 1808: 1807: 1804:Metrizability 1798: 1794: 1790: 1786: 1783: 1780: 1777:. A space is 1776: 1773: 1770: 1767:. A space is 1766: 1763: 1760: 1756: 1753:. A space is 1752: 1749: 1746: 1743:. A space is 1742: 1739: 1736: 1735:pseudocompact 1733:. A space is 1732: 1731:Pseudocompact 1729: 1726: 1723:. A space is 1722: 1719: 1716: 1713:. A space is 1712: 1709: 1706: 1702: 1698: 1695:has a finite 1694: 1690: 1687:. A space is 1686: 1683: 1682: 1673: 1669: 1666:. A space is 1665: 1661: 1658: 1655: 1652:. A space is 1651: 1648: 1645: 1642:. A space is 1641: 1638: 1635: 1631: 1627: 1623: 1619: 1616: 1613: 1609: 1605: 1601: 1597: 1593: 1589: 1585: 1582: 1579: 1575: 1571: 1567: 1563: 1559: 1556: 1553: 1537: 1529: 1525: 1521: 1518: 1510: 1506: 1502: 1499: 1484: 1481: 1475: 1469: 1449: 1446: 1440: 1434: 1414: 1405: 1402: 1399: 1393: 1390: 1382: 1378: 1374: 1370: 1366: 1362: 1358: 1354: 1353:arc-connected 1350: 1346: 1345:Arc-connected 1343: 1340: 1337:. A space is 1336: 1333: 1330: 1326: 1322: 1318: 1314: 1310: 1306: 1302: 1298: 1294: 1290: 1286: 1282: 1278: 1274: 1271: 1268: 1265:. A space is 1264: 1261: 1258: 1255:. A space is 1254: 1251: 1248: 1244: 1241:. A space is 1240: 1237: 1236: 1233:Connectedness 1227: 1224: 1220: 1216: 1213:. A space is 1212: 1210: 1206: 1203: 1199: 1196:. A space is 1195: 1192: 1189: 1185: 1182:. A space is 1181: 1178: 1175: 1171: 1168:. A space is 1167: 1164: 1162:dense subset. 1161: 1157: 1154:. A space is 1153: 1150: 1149: 1147: 1134: 1130: 1127: 1124: 1121:. A space is 1120: 1117: 1110: 1107:. A space is 1106: 1099: 1095: 1089: 1086: 1082: 1079:. A space is 1078: 1075: 1068: 1064: 1058: 1055: 1051: 1048:. A space is 1047: 1044: 1037: 1033: 1027: 1024: 1020: 1017:. A space is 1016: 1013: 1002: 998: 991: 987: 983: 977: 974: 970: 966: 962: 958: 954: 950: 947:. A space is 946: 943: 940: 928: 925:. A space is 924: 920: 914: 911: 907: 903: 899: 895: 891: 888:. A space is 887: 884: 881: 877: 870: 866: 860: 849: 845: 842:. A space is 841: 837: 831: 820: 817:. A space is 816: 812: 806: 803: 799: 795: 791: 787: 783: 779: 775: 772:. A space is 771: 768: 749: 745: 741: 737: 733: 730:. A space is 729: 725: 719: 716: 712: 708: 704: 700: 696: 692: 689:. A space is 688: 684: 678: 677: 676: 674: 668: 643: 623: 600: 594: 587: 584: 569: 562:of the space 561: 542: 536: 529: 526: 511: 485: 479: 468: 453: 446:of the space 430: 420: 416: 415: 413: 384: 381: 374:has property 360: 354: 337: 334: 330: 322:the subspace 309: 306: 303: 300: 270: 267: 256: 253: 239: 236: 229:has property 215: 209: 192: 189: 185: 177: 161: 158: 155: 152: 122: 119: 108: 105: 104: 103: 89: 75: 73: 69: 64: 62: 58: 54: 50: 46: 42: 38: 34: 30: 26: 22: 3134: 3112: 3089: 3042:math/0609092 3032: 3026: 3016: 2904: 2899:Editing help 2881: 2672:completeness 2665: 2532: 2417: 2229: 2164: 2157: 2148:Stone spaces 2139: 2129: 2123: 2111: 2097: 2089: 2085: 2081: 2001: 1997: 1993: 1985: 1981: 1971: 1965: 1953: 1949: 1936: 1926: 1818:metric space 1809: 1796: 1792: 1788: 1784: 1774: 1764: 1750: 1740: 1730: 1720: 1710: 1701:quasicompact 1700: 1696: 1684: 1663: 1659: 1649: 1639: 1633: 1630:identity map 1626:contractible 1621: 1618:Contractible 1617: 1607: 1603: 1599: 1595: 1587: 1583: 1577: 1573: 1569: 1561: 1557: 1504: 1500: 1376: 1372: 1368: 1364: 1360: 1356: 1348: 1344: 1334: 1328: 1324: 1320: 1316: 1312: 1308: 1304: 1300: 1296: 1292: 1288: 1284: 1276: 1272: 1262: 1252: 1238: 1208: 1207: 1193: 1186:if it has a 1179: 1165: 1158:if it has a 1151: 1128: 1118: 1101: 1097: 1090: 1076: 1066: 1059: 1045: 1035: 1028: 1014: 994:Completely T 993: 989: 985: 978: 968: 964: 960: 956: 952: 951:if whenever 944: 922: 915: 909: 905: 901: 897: 893: 892:if whenever 885: 873:completely T 868: 862:Completely T 861: 847: 839: 832: 814: 807: 801: 797: 793: 789: 785: 781: 777: 769: 747: 743: 739: 735: 727: 720: 714: 710: 706: 702: 698: 694: 686: 679: 670: 585: 527: 254: 106: 81: 71: 68:homeomorphic 65: 56: 52: 49:proper class 32: 28: 18: 3035:(1): 1–16. 2935:Chern class 2819:. However, 2668:boundedness 2184:-resolvable 1990:homogeneous 1958:Baire space 1950:Baire space 1769:paracompact 1765:Paracompact 1679:Compactness 1586:. A space 1560:. A space 1379:, i.e., an 1247:clopen sets 1176:local base. 1102:perfectly T 1052:if any two 419:cardinality 145:and subset 82:A property 25:mathematics 3146:Categories 3080:References 2957:cohomology 2907:March 2017 2583:such that 2094:Alexandrov 2088:. A space 2086:Alexandrov 2036:such that 1984:. A space 1976:door space 1972:Door space 1952:. A space 1814:metrizable 1810:Metrizable 1693:open cover 1668:indiscrete 1660:Indiscrete 1620:. A space 1598:such that 1503:. A space 1347:. A space 1275:. A space 1144:See also: 939:consistent 691:Kolmogorov 687:Kolmogorov 661:Separation 107:Hereditary 3061:0021-2172 3008:Citations 2804:→ 2798:: 2772:≅ 2740:π 2725:π 2719:− 2568:≅ 2371:Δ 2332:∅ 2329:≠ 2289:Δ 2260:Δ 2214:κ 2194:κ 2172:κ 2021:→ 2015:: 1761:subcover. 1759:countable 1745:σ-compact 1741:σ-compact 1705:Hausdorff 1691:if every 1552:homotopic 1535:→ 1522:: 1412:→ 1394:: 1381:injective 1243:connected 1239:Connected 1226:subspaces 1219:countably 1215:σ-compact 1204:subcover. 1202:countable 1188:countable 1174:countable 1160:countable 1156:separable 1152:Separable 986:Tychonoff 819:Hausdorff 815:Hausdorff 796:} equals 480:τ 304:⊆ 156:⊆ 61:open sets 41:invariant 3113:Topology 3111:(2000). 3069:14743623 2953:Homology 2863:See also 2232:. Space 1797:monolith 1755:Lindelöf 1751:Lindelöf 1697:subcover 1602:loop in 1211:-compact 1198:Lindelöf 1194:Lindelöf 1123:discrete 746:but not 713:but not 705:but not 176:subspace 39:that is 21:topology 2520:is the 2363:Number 2144:Boolean 2140:Boolean 1689:compact 1685:Compact 1664:trivial 1628:if the 1223:compact 963:, then 904:, then 890:regular 886:Regular 844:Urysohn 840:Urysohn 732:Fréchet 728:Fréchet 586:Density 3123:  3097:  3067:  3059:  2882:is in 2795:arctan 2623:, but 2420:. Set 1962:meagre 1931:Polish 1927:Polish 1327:(1) = 1319:(0) = 1019:normal 1015:Normal 971:} are 848:closed 800:, and 528:Weight 43:under 3065:S2CID 3037:arXiv 2888:prose 1956:is a 1600:every 1427:with 1371:from 1315:with 1299:from 1221:many 1100:, or 967:and { 774:sober 770:Sober 3121:ISBN 3095:ISBN 3057:ISSN 2964:and 2955:and 2884:list 2702:and 2670:and 2603:has 1996:and 1462:and 1323:and 999:. A 908:and 738:and 697:and 417:The 174:the 102:is: 27:, a 3047:doi 3033:166 2304:min 2150:of 2122:of 2092:is 2084:or 2000:in 1662:or 1632:on 1624:is 1590:is 1572:in 1564:is 1550:is 1507:is 1375:to 1363:in 1351:is 1303:to 1291:in 1279:is 1096:or 1065:or 1034:or 992:or 921:or 867:or 838:or 813:or 726:or 685:or 72:not 63:. 31:or 19:In 3148:: 3119:. 3115:. 3063:. 3055:. 3045:. 3031:. 3025:. 2663:. 1359:, 1287:, 988:, 984:, 981:3½ 941:.) 852:2½ 835:2½ 675:. 3129:. 3103:. 3071:. 3049:: 3039:: 2909:) 2905:( 2891:. 2847:Y 2827:X 2807:Y 2801:X 2775:Y 2769:X 2749:) 2743:2 2734:, 2728:2 2716:( 2713:= 2710:Y 2689:R 2685:= 2682:X 2651:P 2631:Y 2611:P 2591:X 2571:Y 2565:X 2545:P 2508:X 2488:X 2468:D 2448:X 2428:D 2403:. 2400:X 2380:) 2377:X 2374:( 2351:. 2348:} 2338:G 2335:, 2326:G 2323:: 2319:| 2315:G 2311:| 2307:{ 2301:= 2298:) 2295:X 2292:( 2269:) 2266:X 2263:( 2240:X 2154:. 2126:. 2124:0 2098:X 2090:X 2062:. 2059:y 2056:= 2053:) 2050:x 2047:( 2044:f 2024:X 2018:X 2012:f 2002:X 1998:y 1994:x 1986:X 1966:X 1954:X 1912:. 1909:T 1889:) 1886:d 1883:( 1880:T 1860:X 1840:) 1837:T 1834:, 1831:X 1828:( 1799:. 1793:X 1789:X 1674:. 1634:X 1622:X 1614:. 1608:X 1604:U 1596:U 1588:X 1578:U 1574:X 1570:x 1562:X 1538:X 1530:1 1526:S 1519:f 1505:X 1485:y 1482:= 1479:) 1476:1 1473:( 1470:p 1450:x 1447:= 1444:) 1441:0 1438:( 1435:p 1415:X 1409:] 1406:1 1403:, 1400:0 1397:[ 1391:f 1377:y 1373:x 1369:f 1365:X 1361:y 1357:x 1349:X 1329:y 1325:p 1321:x 1317:p 1313:X 1309:p 1305:y 1301:x 1297:p 1293:X 1289:y 1285:x 1277:X 1228:. 1209:σ 1113:1 1104:4 1093:6 1091:T 1071:1 1062:5 1060:T 1040:1 1031:4 1029:T 1025:. 1009:0 1005:0 996:3 979:T 975:. 969:p 965:C 961:C 957:p 953:C 935:0 931:0 918:3 916:T 910:p 906:C 902:C 898:p 894:C 875:2 864:2 858:. 856:2 833:T 829:. 827:1 823:2 810:2 808:T 802:p 798:C 794:p 790:p 786:C 782:p 778:C 766:. 764:0 760:1 756:1 752:0 748:y 744:x 740:y 736:x 723:1 721:T 717:. 715:x 711:y 707:y 703:x 699:y 695:x 682:0 680:T 656:. 644:X 624:X 604:) 601:X 598:( 595:d 582:. 570:X 546:) 543:X 540:( 537:w 524:. 512:X 492:| 489:) 486:X 483:( 477:| 466:. 454:X 434:| 431:X 428:| 385:. 382:P 361:) 355:S 350:| 343:T 338:, 335:S 331:( 310:, 307:X 301:S 281:) 276:T 271:, 268:X 265:( 240:. 237:P 216:) 210:S 205:| 198:T 193:, 190:S 186:( 162:, 159:X 153:S 133:) 128:T 123:, 120:X 117:( 90:P 57:X 53:X

Index

topology
mathematics
topological space
invariant
homeomorphisms
proper class
open sets
homeomorphic
subspace
Cardinal function § Cardinal functions in topology
cardinality
basis of the topology
Separation axiom
history of the separation axioms
Kolmogorov
Fréchet
sober
Hausdorff
Urysohn
completely T2
separated by a function
regular
regular Hausdorff
consistent
completely regular
separated by a function
Tychonoff space
normal
partitions of unity
completely normal

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