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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).
2197:. 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 2372: 2770: 2828: 383: 238: 513: 1559: 302: 154: 2711: 2045: 1436: 455: 331: 183: 2157:
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.
1621:. Semi-local simple connectivity, a strictly weaker condition than local simple connectivity, is a necessary condition for the existence of a 1831:. Metrizable spaces are always Hausdorff and paracompact (and hence normal and Tychonoff), and first-countable. Moreover, a topological space 62:
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.
1084:. Completely normal Hausdorff spaces are always normal Hausdorff. 2548:, etc, which are not topological properties. To show a property 2511:
is said to be strongly discrete if every non-isolated point of
1080:. A completely normal space is Hausdorff if and only if it is T 2939: – Association of cohomology classes to principal bundles 2933: – Association of cohomology classes to principal bundles 712:
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
2996: – List of concrete topologies and topological spaces 2765:{\displaystyle Y=(-{\tfrac {\pi }{2}},{\tfrac {\pi }{2}})} 1098:. A perfectly normal space must also be completely normal. 1944:
if it is metrizable with a separable and complete metric.
3104:. Reading, Mass.: Addison-Wesley Pub. Co. p. 369. 2941:
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.
1049:. A normal space is Hausdorff if and only if it is T 66:
possesses that property every space homeomorphic to
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Alternatively, a topological property is a 2954: – Topological invariant in mathematics 2677:For example, the metric space properties of 2358: 2317: 1989:if every subset is open or closed (or both). 502: 487: 444: 438: 3002: – Concept in mathematical knot theory 2107:if arbitrary intersections of open sets in 857:if every two distinct points have disjoint 1508:. Arc-connected spaces are path-connected. 1150: 3061: 3051: 2699: 2544:There are many examples of properties of 2451:is strongly discrete subset of the space 3118: 3097: 627:, the least cardinality of a subset of 14: 3155: 3034:"Resolvability and monotone normality" 1798:. In an ultra-connected compact space 1122:, if it is both perfectly normal and T 815:is the only point with this property. 745:if for every pair of distinct points 704:if for every pair of distinct points 416: 81:or not. To prove that two spaces are 2877: 2685:are not topological properties. Let 1094:if any two disjoint closed sets are 508:{\displaystyle \vert \tau (X)\vert } 89:Properties of topological properties 2850:is complete but not bounded, while 769:if all its singletons are closed. T 24: 2403:is called dispersion character of 2381: 2299: 2270: 1587:has a local base of neighborhoods 1554:{\displaystyle f\colon S^{1}\to X} 353: 297:{\displaystyle (X,{\mathcal {T}})} 286: 208: 149:{\displaystyle (X,{\mathcal {T}})} 138: 25: 3179: 2342: 2263:is maximally resolvable if it is 1710:. Some authors call these spaces 1096:precisely separated by a function 889:if every two distinct points are 268:, if for every topological space 120:, if for every topological space 3163:Properties of topological spaces 2882: 1954: 1814: 1243: 787:if every irreducible closed set 684:history of the separation axioms 27:Mathematical property of a space 1912:is identical with the topology 3025: 2897:format but may read better as 2814: 2759: 2726: 2706:{\displaystyle X=\mathbb {R} } 2535:of some strongly discrete set. 2390: 2384: 2329: 2321: 2308: 2302: 2279: 2273: 2217:-resolvable then it is called 2117:category of topological spaces 2063: 2057: 2040:{\displaystyle f\colon X\to X} 2031: 1899: 1893: 1883:such that the metric topology 1850: 1838: 1802:every open cover must contain 1689: 1545: 1489: 1483: 1454: 1448: 1422: 1419: 1407: 614: 608: 556: 550: 499: 493: 360: 291: 275: 215: 143: 127: 13: 1: 3090: 3039:Israel Journal of Mathematics 2960: – Mathematical property 2870:is bounded but not complete. 1603:semi-locally simply connected 1595:Semi-locally simply connected 1431:{\displaystyle f\colon \to X} 1260:are the empty set and itself. 1067:have disjoint neighbourhoods. 923:have disjoint neighbourhoods. 671: 569:, the least cardinality of a 450:{\displaystyle \vert X\vert } 412:Common topological properties 326:{\displaystyle S\subseteq X,} 178:{\displaystyle S\subseteq X,} 3018: 1001:Completely regular Hausdorff 720:, or an open set containing 7: 2873: 1985:. A topological space is a 1827:if it is homeomorphic to a 1078:Completely normal Hausdorff 791:has a unique generic point 10: 3184: 3006:Topological quantum number 2540:Non-topological properties 2396:{\displaystyle \Delta (X)} 2285:{\displaystyle \Delta (X)} 1768:if every open cover has a 1211:if every open cover has a 1154: 1120:perfectly normal Hausdorff 1109:Perfectly normal Hausdorff 803:such that the closure of { 675: 420: 3098:Willard, Stephen (1970). 3063:10.1007/s11856-008-1017-y 2015:there is a homeomorphism 1975:in itself. Equivalently, 1591:that is simply connected. 1318:, i.e., a continuous map 1140:Number of isolated points 1014:is a completely regular T 2791:{\displaystyle X\cong Y} 2587:{\displaystyle X\cong Y} 1714:and reserve compact for 1577:locally simply connected 1569:Locally simply connected 1366:if for every two points 1294:if for every two points 948:, so the terminology is 2906:converting this article 2230:{\displaystyle \kappa } 2210:{\displaystyle \kappa } 2188:{\displaystyle \kappa } 2078:{\displaystyle f(x)=y.} 1993:Topological Homogeneity 1151:Countability conditions 1146:of a topological space. 984:separated by a function 891:separated by a function 2937:Characteristic numbers 2864: 2844: 2824: 2798:via the homeomorphism 2792: 2766: 2707: 2668: 2648: 2628: 2608: 2588: 2562: 2525: 2505: 2485: 2465: 2445: 2420: 2397: 2368: 2286: 2257: 2231: 2211: 2189: 2079: 2041: 1929: 1906: 1877: 1857: 1796:Ultraconnected compact 1555: 1502: 1501:{\displaystyle p(1)=y} 1467: 1466:{\displaystyle p(0)=x} 1432: 1350:locally path-connected 1346:Locally path-connected 1228:if it is the union of 795:. In other words, if 661: 641: 621: 587: 563: 529: 509: 471: 451: 402: 379: 327: 298: 257: 234: 179: 150: 107: 2865: 2845: 2825: 2793: 2767: 2708: 2669: 2649: 2629: 2609: 2589: 2563: 2526: 2506: 2486: 2466: 2446: 2421: 2398: 2369: 2287: 2258: 2232: 2212: 2190: 2080: 2042: 1930: 1907: 1878: 1858: 1856:{\displaystyle (X,T)} 1556: 1503: 1468: 1433: 1183:if every point has a 1157:Axiom of countability 662: 642: 622: 588: 571:basis of the topology 564: 530: 510: 472: 452: 403: 380: 328: 299: 258: 235: 180: 151: 108: 44:topological invariant 34:and related areas of 18:Topological invariant 2958:Fixed-point property 2952:Euler characteristic 2931:Characteristic class 2854: 2834: 2802: 2776: 2717: 2689: 2658: 2638: 2618: 2598: 2572: 2552: 2515: 2495: 2475: 2455: 2435: 2407: 2378: 2296: 2267: 2247: 2241:Maximally resolvable 2221: 2201: 2179: 2170:Reidemeister torsion 2119:and continuous maps. 2051: 2019: 1940:. A space is called 1916: 1905:{\displaystyle T(d)} 1887: 1867: 1835: 1726:sequentially compact 1722:Sequentially compact 1526: 1477: 1442: 1398: 1322::  →  1278:totally disconnected 1274:Totally disconnected 966:is a closed set and 940:if it is a regular T 907:is a closed set and 880:completely Hausdorff 651: 631: 620:{\displaystyle d(X)} 602: 577: 562:{\displaystyle w(X)} 544: 519: 484: 461: 435: 389: 337: 308: 272: 244: 192: 160: 124: 97: 40:topological property 2292:-resolvable, where 2131:inductive dimension 1999:is (topologically) 1617:is contractible in 1034:partitions of unity 865:spaces are always T 836:spaces are always T 773:spaces are always T 46:is a property of a 2994:List of topologies 2908:, if appropriate. 2860: 2840: 2820: 2788: 2762: 2757: 2742: 2703: 2664: 2644: 2624: 2604: 2584: 2558: 2533:accumulation point 2521: 2501: 2481: 2461: 2441: 2419:{\displaystyle X.} 2416: 2393: 2364: 2356: 2282: 2253: 2227: 2207: 2185: 2113:finitely generated 2093:Finitely generated 2087:topological groups 2075: 2037: 1948:Locally metrizable 1928:{\displaystyle T.} 1925: 1902: 1873: 1853: 1565:to a constant map. 1551: 1498: 1463: 1428: 1378:, there is an arc 1306:, there is a path 970:is a point not in 960:completely regular 956:Completely regular 911:is a point not in 657: 637: 617: 583: 559: 525: 505: 467: 447: 417:Cardinal functions 401:{\displaystyle P.} 398: 375: 323: 304:and closed subset 294: 256:{\displaystyle P.} 253: 230: 175: 146: 103: 3120:Munkres, James R. 3000:Quantum invariant 2927: 2926: 2863:{\displaystyle Y} 2843:{\displaystyle X} 2756: 2741: 2667:{\displaystyle P} 2647:{\displaystyle Y} 2627:{\displaystyle P} 2607:{\displaystyle X} 2561:{\displaystyle P} 2524:{\displaystyle X} 2504:{\displaystyle X} 2484:{\displaystyle D} 2471:if the points in 2464:{\displaystyle X} 2444:{\displaystyle D} 2429:Strongly discrete 2355: 2256:{\displaystyle X} 1876:{\displaystyle X} 1736:countably compact 1732:Countably compact 1268:locally connected 1264:Locally connected 1061:completely normal 1057:Completely normal 938:regular Hausdorff 934:Regular Hausdorff 861:neighbourhoods. T 761:. (Compare with T 660:{\displaystyle X} 647:whose closure is 640:{\displaystyle X} 586:{\displaystyle X} 528:{\displaystyle X} 470:{\displaystyle X} 266:Weakly hereditary 106:{\displaystyle P} 48:topological space 16:(Redirected from 3175: 3141: 3115: 3101:General topology 3084: 3083: 3065: 3055: 3029: 2977:Cohomotopy group 2942: 2922: 2919: 2913: 2904:You can help by 2886: 2885: 2878: 2869: 2867: 2866: 2861: 2849: 2847: 2846: 2841: 2829: 2827: 2826: 2821: 2797: 2795: 2794: 2789: 2771: 2769: 2768: 2763: 2758: 2749: 2743: 2734: 2712: 2710: 2709: 2704: 2702: 2673: 2671: 2670: 2665: 2653: 2651: 2650: 2645: 2633: 2631: 2630: 2625: 2613: 2611: 2610: 2605: 2593: 2591: 2590: 2585: 2567: 2565: 2564: 2559: 2530: 2528: 2527: 2522: 2510: 2508: 2507: 2502: 2490: 2488: 2487: 2482: 2470: 2468: 2467: 2462: 2450: 2448: 2447: 2442: 2425: 2423: 2422: 2417: 2402: 2400: 2399: 2394: 2373: 2371: 2370: 2365: 2357: 2353: 2332: 2324: 2291: 2289: 2288: 2283: 2262: 2260: 2259: 2254: 2236: 2234: 2233: 2228: 2216: 2214: 2213: 2208: 2194: 2192: 2191: 2186: 2163:Boolean algebras 2127:zero-dimensional 2123:Zero-dimensional 2089:are homogeneous. 2084: 2082: 2081: 2076: 2046: 2044: 2043: 2038: 1934: 1932: 1931: 1926: 1911: 1909: 1908: 1903: 1882: 1880: 1879: 1874: 1862: 1860: 1859: 1854: 1683:trivial topology 1560: 1558: 1557: 1552: 1544: 1543: 1520:simply connected 1512:Simply connected 1507: 1505: 1504: 1499: 1472: 1470: 1469: 1464: 1437: 1435: 1434: 1429: 1195:second-countable 1191:Second-countable 1142:. The number of 1092:perfectly normal 1088:Perfectly normal 1047:Normal Hausdorff 678:Separation axiom 666: 664: 663: 658: 646: 644: 643: 638: 626: 624: 623: 618: 592: 590: 589: 584: 568: 566: 565: 560: 534: 532: 531: 526: 514: 512: 511: 506: 480:The cardinality 476: 474: 473: 468: 456: 454: 453: 448: 407: 405: 404: 399: 384: 382: 381: 376: 374: 370: 369: 368: 363: 357: 356: 332: 330: 329: 324: 303: 301: 300: 295: 290: 289: 262: 260: 259: 254: 239: 237: 236: 231: 229: 225: 224: 223: 218: 212: 211: 184: 182: 181: 176: 155: 153: 152: 147: 142: 141: 112: 110: 109: 104: 21: 3183: 3182: 3178: 3177: 3176: 3174: 3173: 3172: 3153: 3152: 3144: 3138: 3112: 3093: 3088: 3087: 3030: 3026: 3021: 2940: 2923: 2917: 2914: 2903: 2887: 2883: 2876: 2855: 2852: 2851: 2835: 2832: 2831: 2803: 2800: 2799: 2777: 2774: 2773: 2747: 2732: 2718: 2715: 2714: 2698: 2690: 2687: 2686: 2659: 2656: 2655: 2639: 2636: 2635: 2619: 2616: 2615: 2599: 2596: 2595: 2573: 2570: 2569: 2553: 2550: 2549: 2542: 2516: 2513: 2512: 2496: 2493: 2492: 2476: 2473: 2472: 2456: 2453: 2452: 2436: 2433: 2432: 2408: 2405: 2404: 2379: 2376: 2375: 2351: 2328: 2320: 2297: 2294: 2293: 2268: 2265: 2264: 2248: 2245: 2244: 2222: 2219: 2218: 2202: 2199: 2198: 2180: 2177: 2176: 2145:almost discrete 2141:Almost discrete 2115:members of the 2052: 2049: 2048: 2020: 2017: 2016: 1957: 1917: 1914: 1913: 1888: 1885: 1884: 1868: 1865: 1864: 1836: 1833: 1832: 1817: 1790:locally compact 1786:Locally compact 1692: 1623:universal cover 1579:if every point 1539: 1535: 1527: 1524: 1523: 1478: 1475: 1474: 1443: 1440: 1439: 1399: 1396: 1395: 1394:continuous map 1246: 1181:first-countable 1177:First-countable 1159: 1153: 1144:isolated points 1125: 1116: 1105: 1083: 1074: 1052: 1043: 1021: 1017: 1012:Tychonoff space 1008: 993: 947: 943: 930: 887: 876: 868: 864: 847: 839: 835: 822: 776: 772: 768: 764: 735: 694: 680: 674: 652: 649: 648: 632: 629: 628: 603: 600: 599: 578: 575: 574: 545: 542: 541: 520: 517: 516: 485: 482: 481: 462: 459: 458: 436: 433: 432: 425: 419: 414: 390: 387: 386: 364: 359: 358: 352: 351: 344: 340: 338: 335: 334: 309: 306: 305: 285: 284: 273: 270: 269: 245: 242: 241: 219: 214: 213: 207: 206: 199: 195: 193: 190: 189: 161: 158: 157: 137: 136: 125: 122: 121: 98: 95: 94: 91: 28: 23: 22: 15: 12: 11: 5: 3181: 3171: 3170: 3168:Homeomorphisms 3165: 3143: 3142: 3136: 3116: 3110: 3094: 3092: 3089: 3086: 3085: 3023: 3022: 3020: 3017: 3016: 3015: 3012:Winding number 3009: 3003: 2997: 2991: 2988:Linking number 2985: 2982:Knot invariant 2979: 2973:Homotopy group 2970: 2961: 2955: 2949: 2943: 2934: 2925: 2924: 2890: 2888: 2881: 2875: 2872: 2859: 2839: 2819: 2816: 2813: 2810: 2807: 2787: 2784: 2781: 2761: 2755: 2752: 2746: 2740: 2737: 2731: 2728: 2725: 2722: 2701: 2697: 2694: 2663: 2654:does not have 2643: 2623: 2603: 2583: 2580: 2577: 2557: 2541: 2538: 2537: 2536: 2520: 2500: 2480: 2460: 2440: 2426: 2415: 2412: 2392: 2389: 2386: 2383: 2363: 2360: 2350: 2347: 2344: 2341: 2338: 2335: 2331: 2327: 2323: 2319: 2316: 2313: 2310: 2307: 2304: 2301: 2281: 2278: 2275: 2272: 2252: 2238: 2237:-irresolvable. 2226: 2206: 2184: 2173: 2166: 2148: 2138: 2120: 2090: 2074: 2071: 2068: 2065: 2062: 2059: 2056: 2036: 2033: 2030: 2027: 2024: 1990: 1980: 1956: 1953: 1952: 1951: 1945: 1935: 1924: 1921: 1901: 1898: 1895: 1892: 1872: 1852: 1849: 1846: 1843: 1840: 1816: 1813: 1812: 1811: 1793: 1783: 1773: 1759: 1749: 1739: 1729: 1719: 1691: 1688: 1687: 1686: 1668: 1665:ultraconnected 1661:Ultraconnected 1658: 1655:hyperconnected 1651:Hyperconnected 1648: 1626: 1592: 1566: 1550: 1547: 1542: 1538: 1534: 1531: 1509: 1497: 1494: 1491: 1488: 1485: 1482: 1462: 1459: 1456: 1453: 1450: 1447: 1427: 1424: 1421: 1418: 1415: 1412: 1409: 1406: 1403: 1353: 1343: 1292:path-connected 1284:Path-connected 1281: 1271: 1261: 1245: 1242: 1241: 1240: 1216: 1202: 1188: 1174: 1152: 1149: 1148: 1147: 1137: 1130:Discrete space 1127: 1123: 1114: 1103: 1099: 1085: 1081: 1072: 1068: 1065:separated sets 1054: 1050: 1041: 1037: 1023: 1019: 1015: 1006: 991: 987: 953: 945: 941: 928: 924: 894: 885: 882:. A space is 874: 870: 866: 862: 845: 841: 837: 833: 820: 816: 778: 774: 770: 766: 762: 733: 729: 692: 676:Main article: 673: 670: 669: 668: 656: 636: 616: 613: 610: 607: 594: 582: 558: 555: 552: 549: 536: 524: 504: 501: 498: 495: 492: 489: 478: 466: 446: 443: 440: 421:Main article: 418: 415: 413: 410: 409: 408: 397: 394: 373: 367: 362: 355: 350: 347: 343: 322: 319: 316: 313: 293: 288: 283: 280: 277: 263: 252: 249: 228: 222: 217: 210: 205: 202: 198: 174: 171: 168: 165: 145: 140: 135: 132: 129: 102: 90: 87: 56:homeomorphisms 26: 9: 6: 4: 3: 2: 3180: 3169: 3166: 3164: 3161: 3160: 3158: 3151: 3150: 3139: 3137:0-13-181629-2 3133: 3129: 3128:Prentice-Hall 3125: 3121: 3117: 3113: 3111:9780486434797 3107: 3103: 3102: 3096: 3095: 3081: 3077: 3073: 3069: 3064: 3059: 3054: 3049: 3045: 3041: 3040: 3035: 3028: 3024: 3013: 3010: 3007: 3004: 3001: 2998: 2995: 2992: 2989: 2986: 2983: 2980: 2978: 2974: 2971: 2969: 2965: 2962: 2959: 2956: 2953: 2950: 2947: 2944: 2938: 2935: 2932: 2929: 2928: 2921: 2912:is available. 2911: 2907: 2901: 2900: 2896: 2891:This article 2889: 2880: 2879: 2871: 2857: 2837: 2817: 2811: 2808: 2805: 2785: 2782: 2779: 2753: 2750: 2744: 2738: 2735: 2729: 2723: 2720: 2695: 2692: 2684: 2680: 2675: 2661: 2641: 2621: 2601: 2581: 2578: 2575: 2555: 2547: 2546:metric spaces 2534: 2518: 2498: 2478: 2458: 2438: 2430: 2427: 2413: 2410: 2387: 2361: 2354: is open 2348: 2345: 2339: 2336: 2333: 2325: 2311: 2305: 2276: 2250: 2242: 2239: 2224: 2204: 2196: 2182: 2174: 2172: 2171: 2167: 2164: 2160: 2156: 2153:. A space is 2152: 2149: 2146: 2143:. A space is 2142: 2139: 2136: 2132: 2128: 2125:. A space is 2124: 2121: 2118: 2114: 2110: 2106: 2102: 2098: 2094: 2091: 2088: 2072: 2069: 2066: 2060: 2054: 2034: 2028: 2025: 2022: 2014: 2010: 2006: 2003:if for every 2002: 1998: 1994: 1991: 1988: 1984: 1981: 1978: 1974: 1971:if it is not 1970: 1966: 1962: 1959: 1958: 1955:Miscellaneous 1949: 1946: 1943: 1939: 1936: 1922: 1919: 1896: 1890: 1870: 1847: 1844: 1841: 1830: 1826: 1823:. A space is 1822: 1819: 1818: 1815:Metrizability 1809: 1805: 1801: 1797: 1794: 1791: 1788:. A space is 1787: 1784: 1781: 1778:. A space is 1777: 1774: 1771: 1767: 1764:. A space is 1763: 1760: 1757: 1754:. A space is 1753: 1750: 1747: 1746:pseudocompact 1744:. A space is 1743: 1742:Pseudocompact 1740: 1737: 1734:. A space is 1733: 1730: 1727: 1724:. A space is 1723: 1720: 1717: 1713: 1709: 1706:has a finite 1705: 1701: 1698:. A space is 1697: 1694: 1693: 1684: 1680: 1677:. A space is 1676: 1672: 1669: 1666: 1663:. A space is 1662: 1659: 1656: 1653:. A space is 1652: 1649: 1646: 1642: 1638: 1634: 1630: 1627: 1624: 1620: 1616: 1612: 1608: 1604: 1600: 1596: 1593: 1590: 1586: 1582: 1578: 1574: 1570: 1567: 1564: 1548: 1540: 1536: 1532: 1529: 1521: 1517: 1513: 1510: 1495: 1492: 1486: 1480: 1460: 1457: 1451: 1445: 1425: 1416: 1413: 1410: 1404: 1401: 1393: 1389: 1385: 1381: 1377: 1373: 1369: 1365: 1364:arc-connected 1361: 1357: 1356:Arc-connected 1354: 1351: 1348:. A space is 1347: 1344: 1341: 1337: 1333: 1329: 1325: 1321: 1317: 1313: 1309: 1305: 1301: 1297: 1293: 1289: 1285: 1282: 1279: 1276:. A space is 1275: 1272: 1269: 1266:. A space is 1265: 1262: 1259: 1255: 1252:. A space is 1251: 1248: 1247: 1244:Connectedness 1238: 1235: 1231: 1227: 1224:. A space is 1223: 1221: 1217: 1214: 1210: 1207:. A space is 1206: 1203: 1200: 1196: 1193:. A space is 1192: 1189: 1186: 1182: 1179:. A space is 1178: 1175: 1173:dense subset. 1172: 1168: 1165:. A space is 1164: 1161: 1160: 1158: 1145: 1141: 1138: 1135: 1132:. A space is 1131: 1128: 1121: 1118:. A space is 1117: 1110: 1106: 1100: 1097: 1093: 1090:. A space is 1089: 1086: 1079: 1075: 1069: 1066: 1062: 1059:. A space is 1058: 1055: 1048: 1044: 1038: 1035: 1031: 1028:. A space is 1027: 1024: 1013: 1009: 1002: 998: 994: 988: 985: 981: 977: 973: 969: 965: 961: 958:. A space is 957: 954: 951: 939: 936:. A space is 935: 931: 925: 922: 918: 914: 910: 906: 902: 899:. A space is 898: 895: 892: 888: 881: 877: 871: 860: 856: 853:. A space is 852: 848: 842: 831: 828:. A space is 827: 823: 817: 814: 810: 806: 802: 798: 794: 790: 786: 783:. A space is 782: 779: 760: 756: 752: 748: 744: 741:. A space is 740: 736: 730: 727: 723: 719: 715: 711: 707: 703: 700:. A space is 699: 695: 689: 688: 687: 685: 679: 654: 634: 611: 605: 598: 595: 580: 573:of the space 572: 553: 547: 540: 537: 522: 496: 490: 479: 464: 457:of the space 441: 431: 427: 426: 424: 395: 392: 385:has property 371: 365: 348: 345: 341: 333:the subspace 320: 317: 314: 311: 281: 278: 267: 264: 250: 247: 240:has property 226: 220: 203: 200: 196: 188: 172: 169: 166: 163: 133: 130: 119: 116: 115: 114: 100: 86: 84: 80: 75: 73: 69: 65: 61: 57: 53: 49: 45: 41: 37: 33: 19: 3145: 3123: 3100: 3053:math/0609092 3043: 3037: 3027: 2915: 2910:Editing help 2892: 2683:completeness 2676: 2543: 2428: 2240: 2175: 2168: 2159:Stone spaces 2150: 2140: 2134: 2122: 2108: 2100: 2096: 2092: 2012: 2008: 2004: 1996: 1992: 1982: 1976: 1964: 1960: 1947: 1937: 1829:metric space 1820: 1807: 1803: 1799: 1795: 1785: 1775: 1761: 1751: 1741: 1731: 1721: 1712:quasicompact 1711: 1707: 1695: 1674: 1670: 1660: 1650: 1644: 1641:identity map 1637:contractible 1632: 1629:Contractible 1628: 1618: 1614: 1610: 1606: 1598: 1594: 1588: 1584: 1580: 1572: 1568: 1515: 1511: 1387: 1383: 1379: 1375: 1371: 1367: 1359: 1355: 1345: 1339: 1335: 1331: 1327: 1323: 1319: 1315: 1311: 1307: 1303: 1299: 1295: 1287: 1283: 1273: 1263: 1249: 1219: 1218: 1204: 1197:if it has a 1190: 1176: 1169:if it has a 1162: 1139: 1129: 1112: 1108: 1101: 1087: 1077: 1070: 1056: 1046: 1039: 1025: 1005:Completely T 1004: 1000: 996: 989: 979: 975: 971: 967: 963: 962:if whenever 955: 933: 926: 920: 916: 912: 908: 904: 903:if whenever 896: 884:completely T 879: 873:Completely T 872: 858: 850: 843: 825: 818: 812: 808: 804: 800: 796: 792: 788: 780: 758: 754: 750: 746: 738: 731: 725: 721: 717: 713: 709: 705: 697: 690: 681: 596: 538: 265: 117: 92: 82: 79:homeomorphic 76: 67: 63: 60:proper class 43: 39: 29: 3046:(1): 1–16. 2946:Chern class 2830:. However, 2679:boundedness 2195:-resolvable 2001:homogeneous 1969:Baire space 1961:Baire space 1780:paracompact 1776:Paracompact 1690:Compactness 1597:. A space 1571:. A space 1390:, i.e., an 1258:clopen sets 1187:local base. 1113:perfectly T 1063:if any two 430:cardinality 156:and subset 93:A property 36:mathematics 3157:Categories 3091:References 2968:cohomology 2918:March 2017 2594:such that 2105:Alexandrov 2099:. A space 2097:Alexandrov 2047:such that 1995:. A space 1987:door space 1983:Door space 1963:. A space 1825:metrizable 1821:Metrizable 1704:open cover 1679:indiscrete 1671:Indiscrete 1631:. A space 1609:such that 1514:. A space 1358:. A space 1286:. A space 1155:See also: 950:consistent 702:Kolmogorov 698:Kolmogorov 672:Separation 118:Hereditary 3072:0021-2172 3019:Citations 2815:→ 2809:: 2783:≅ 2751:π 2736:π 2730:− 2579:≅ 2382:Δ 2343:∅ 2340:≠ 2300:Δ 2271:Δ 2225:κ 2205:κ 2183:κ 2032:→ 2026:: 1772:subcover. 1770:countable 1756:σ-compact 1752:σ-compact 1716:Hausdorff 1702:if every 1563:homotopic 1546:→ 1533:: 1423:→ 1405:: 1392:injective 1254:connected 1250:Connected 1237:subspaces 1230:countably 1226:σ-compact 1215:subcover. 1213:countable 1199:countable 1185:countable 1171:countable 1167:separable 1163:Separable 997:Tychonoff 830:Hausdorff 826:Hausdorff 807:} equals 491:τ 315:⊆ 167:⊆ 72:open sets 52:invariant 3124:Topology 3122:(2000). 3080:14743623 2964:Homology 2874:See also 2243:. Space 1808:monolith 1766:Lindelöf 1762:Lindelöf 1708:subcover 1613:loop in 1222:-compact 1209:Lindelöf 1205:Lindelöf 1134:discrete 757:but not 724:but not 716:but not 187:subspace 50:that is 32:topology 2531:is the 2374:Number 2155:Boolean 2151:Boolean 1700:compact 1696:Compact 1675:trivial 1639:if the 1234:compact 974:, then 915:, then 901:regular 897:Regular 855:Urysohn 851:Urysohn 743:Fréchet 739:Fréchet 597:Density 3134:  3108:  3078:  3070:  2893:is in 2806:arctan 2634:, but 2431:. Set 1973:meagre 1942:Polish 1938:Polish 1338:(1) = 1330:(0) = 1030:normal 1026:Normal 982:} are 859:closed 811:, and 539:Weight 54:under 3076:S2CID 3048:arXiv 2899:prose 1967:is a 1611:every 1438:with 1382:from 1326:with 1310:from 1232:many 1111:, or 978:and { 785:sober 781:Sober 3132:ISBN 3106:ISBN 3068:ISSN 2975:and 2966:and 2895:list 2713:and 2681:and 2614:has 2007:and 1473:and 1334:and 1010:. A 919:and 749:and 708:and 428:The 185:the 113:is: 38:, a 3058:doi 3044:166 2315:min 2161:of 2133:of 2103:is 2095:or 2011:in 1673:or 1643:on 1635:is 1601:is 1583:in 1575:is 1561:is 1518:is 1386:to 1374:in 1362:is 1314:to 1302:in 1290:is 1107:or 1076:or 1045:or 1003:or 932:or 878:or 849:or 824:or 737:or 696:or 83:not 74:. 42:or 30:In 3159:: 3130:. 3126:. 3074:. 3066:. 3056:. 3042:. 3036:. 2674:. 1370:, 1298:, 999:, 995:, 992:3½ 952:.) 863:2½ 846:2½ 686:. 3140:. 3114:. 3082:. 3060:: 3050:: 2920:) 2916:( 2902:. 2858:Y 2838:X 2818:Y 2812:X 2786:Y 2780:X 2760:) 2754:2 2745:, 2739:2 2727:( 2724:= 2721:Y 2700:R 2696:= 2693:X 2662:P 2642:Y 2622:P 2602:X 2582:Y 2576:X 2556:P 2519:X 2499:X 2479:D 2459:X 2439:D 2414:. 2411:X 2391:) 2388:X 2385:( 2362:. 2359:} 2349:G 2346:, 2337:G 2334:: 2330:| 2326:G 2322:| 2318:{ 2312:= 2309:) 2306:X 2303:( 2280:) 2277:X 2274:( 2251:X 2165:. 2137:. 2135:0 2109:X 2101:X 2073:. 2070:y 2067:= 2064:) 2061:x 2058:( 2055:f 2035:X 2029:X 2023:f 2013:X 2009:y 2005:x 1997:X 1977:X 1965:X 1923:. 1920:T 1900:) 1897:d 1894:( 1891:T 1871:X 1851:) 1848:T 1845:, 1842:X 1839:( 1810:. 1804:X 1800:X 1685:. 1645:X 1633:X 1625:. 1619:X 1615:U 1607:U 1599:X 1589:U 1585:X 1581:x 1573:X 1549:X 1541:1 1537:S 1530:f 1516:X 1496:y 1493:= 1490:) 1487:1 1484:( 1481:p 1461:x 1458:= 1455:) 1452:0 1449:( 1446:p 1426:X 1420:] 1417:1 1414:, 1411:0 1408:[ 1402:f 1388:y 1384:x 1380:f 1376:X 1372:y 1368:x 1360:X 1340:y 1336:p 1332:x 1328:p 1324:X 1320:p 1316:y 1312:x 1308:p 1304:X 1300:y 1296:x 1288:X 1239:. 1220:σ 1124:1 1115:4 1104:6 1102:T 1082:1 1073:5 1071:T 1051:1 1042:4 1040:T 1036:. 1020:0 1016:0 1007:3 990:T 986:. 980:p 976:C 972:C 968:p 964:C 946:0 942:0 929:3 927:T 921:p 917:C 913:C 909:p 905:C 886:2 875:2 869:. 867:2 844:T 840:. 838:1 834:2 821:2 819:T 813:p 809:C 805:p 801:p 797:C 793:p 789:C 777:. 775:0 771:1 767:1 763:0 759:y 755:x 751:y 747:x 734:1 732:T 728:. 726:x 722:y 718:y 714:x 710:y 706:x 693:0 691:T 667:. 655:X 635:X 615:) 612:X 609:( 606:d 593:. 581:X 557:) 554:X 551:( 548:w 535:. 523:X 503:| 500:) 497:X 494:( 488:| 477:. 465:X 445:| 442:X 439:| 396:. 393:P 372:) 366:S 361:| 354:T 349:, 346:S 342:( 321:, 318:X 312:S 292:) 287:T 282:, 279:X 276:( 251:. 248:P 227:) 221:S 216:| 209:T 204:, 201:S 197:( 173:, 170:X 164:S 144:) 139:T 134:, 131:X 128:( 101:P 68:X 64:X 20:)

Index

Topological invariant
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

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