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Classification of manifolds

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for low-dimensional manifolds?", meaning "If surgery worked in low dimensions, what would low-dimensional manifolds look like?" One can then compare the actual theory of low-dimensional manifolds to the low-dimensional analog of high-dimensional manifolds, and see if low-dimensional manifolds behave
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One can take a low-dimensional point of view on high-dimensional manifolds and ask "Which high-dimensional manifolds are geometrizable?", for various notions of geometrizable (cut into geometrizable pieces as in 3 dimensions, into symplectic manifolds, and so forth). In dimension 4 and above not all
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Thus dimension 4 differentiable manifolds are the most complicated: they are neither geometrizable (as in lower dimension), nor are they classified by surgery (as in higher dimension or topologically), and they exhibit unusual phenomena, most strikingly the uncountably infinitely many
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Being homogeneous (away from any boundary), manifolds have no local point-set invariants, other than their dimension and boundary versus interior, and the most used global point-set properties are compactness and connectedness. Conventional names for combinations of these are:
1121:, 4-manifolds are classified by surgery, the differentiable classification question is phrased in terms of "differentiable structures": "which (topological) 4-manifolds admit a differentiable structure, and on those that do, how many differentiable structures are there?" 51:"Low dimensions" means dimensions up to 4; "high dimensions" means 5 or more dimensions. The case of dimension 4 is somehow a boundary case, as it manifests "low dimensional" behaviour smoothly (but not topologically); see 1022:
There is a unique connected 0-dimensional manifold, namely the point, and disconnected 0-dimensional manifolds are just discrete sets, classified by cardinality. They have no geometry, and their study is combinatorics.
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The point-set classification is basic—one generally fixes point-set assumptions and then studies that class of manifold. The most frequently classified class of manifolds is closed, connected manifolds.
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These functors are in general neither one-to-one nor onto on objects; these failures are generally referred to in terms of "structure", as follows. A topological manifold that is in the image of
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is said to "admit a differentiable structure", and the fiber over a given topological manifold is "the different differentiable structures on the given topological manifold".
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Different categories of manifolds yield different classifications; these are related by the notion of "structure", and more general categories have neater theories.
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This phenomenon is evident already for surfaces: there is a single orientable (and a single non-orientable) closed surface with positive curvature (the sphere and
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In relative dimension, a submersion with compact domain is a fiber bundle (just as in codimension 0 = relative dimension 0), which are classified algebraically.
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Four-dimensional manifolds are the most unusual: they are not geometrizable (as in lower dimensions), and surgery works topologically, but not differentiably.
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and characteristic numbers are the corresponding generalized homological invariants, but they do not classify manifolds in higher dimension (they are not a
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Bull. Amer. Math. Soc. Volume 82, Number 5 (1976), 759-761; M. Kreck, Bordism of diffeomorphisms and related topics, Springer Lect. Notes 1069 (1984)
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Proceedings of the international congress of mathematicians 2018, ICM 2018, Rio de Janeiro, Brazil, August 1–9, 2018. Volume III. Invited lectures
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This ineffectiveness is a fundamental reason why surgery theory does not classify manifolds up to homeomorphism. Instead, for any fixed manifold
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For maps, the appropriate notion of "low dimension" is for some purposes "self maps of low-dimensional manifolds", and for other purposes "low
108:: for instance, a differentiable manifold is also a topological manifold, and a differentiable map is also continuous, so there is a functor 2449: 2391: 217:. The most familiar example is orientability: some manifolds are orientable, some are not, and orientable manifolds admit 2 orientations. 97:. There are many different notions of "manifold", and corresponding notions of "map between manifolds", each of which yields a different 1678: 648:, there is no algorithm for determining if they are isomorphic (homeomorphic, diffeomorphic). This is due to the unsolvability of the 1702: 1897: 1026:
A connected compact 1-dimensional manifold without boundary is homeomorphic (or diffeomorphic if it is smooth) to the circle. A
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is a compact manifold, possibly with boundary, and not necessarily connected (but necessarily with finitely many components).
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Low-dimensional manifolds are classified by geometric structure; high-dimensional manifolds are classified algebraically, by
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There are two usual ways to give a classification: explicitly, by an enumeration, or implicitly, in terms of invariants.
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High dimension manifolds (dimension 5 and more differentiably, dimension 4 and more topologically) are classified by
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requires 2+1 dimensions (2 space, 1 time), hence the two Whitney disks of surgery theory require 2+2+1=5 dimensions.
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Four-manifolds often admit many unusual differentiable structures, most strikingly the uncountably infinitely many
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Conversely, one can take a high-dimensional point of view on low-dimensional manifolds and ask "What does surgery
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Maps from the circle into the 3-sphere (or more generally any 3-dimensional manifold) are studied as part of
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Cobordism groups (the bordism groups of a point) are computed, but the bordism groups of a space (such as
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Particularly topologically interesting classes of maps include embeddings, immersions, and submersions.
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dimension (meaning more than 2), embeddings are classified by surgery, while in low codimension or in
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of manifolds up to various equivalences, and there are many results and open questions in this area.
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In codimension 2, particularly embeddings of 1-dimensional manifolds in 3-dimensional ones, one has
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Every connected closed 2-dimensional manifold (surface) admits a constant curvature metric, by the
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has more structure: in Diff it is simply a set, but in Top it is a group, and functorially so.
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Navas, Andres (2018). "Group actions on 1-manifolds: a list of very concrete open questions".
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In codimension 1, a codimension 1 embedding separates a manifold, and these are tractable.
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Every closed 3-dimensional manifold can be cut into pieces that are geometrizable, by the
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In dimension 5 and above (and 4 dimensions topologically), manifolds are classified by
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is a manifold without boundary (not necessarily connected), with no compact component.
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The study of maps of 1-dimensional manifolds are a non-trivial area. For example:
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show that manifolds with positive curvature are constrained, most dramatically the
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Groups of diffeomorphisms of 1-manifolds are quite difficult to understand finely
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Middle dimension manifolds (dimension 4 differentiably) exhibit exotic phenomena.
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is a basic question, about which much is known, and many open questions remain.
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In codimension greater than 2, embeddings are classified by surgery theory.
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More precisely, what is the structure of the set of additional structures?
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More subtly, dimension 5 is the cut-off because the middle dimension has
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Diffeomorphisms up to cobordism have been classified by Matthias Kreck
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Kreck, Matthias (2000). "A guide to the classification of manifolds".
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of a given high-dimensional manifold, much less a classification.
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is a compact manifold without boundary, not necessarily connected.
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Positive curvature is constrained, negative curvature is generic.
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manifolds are geometrizable, but they are an interesting class.
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Positive curvature is constrained, negative curvature is generic
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If it admits an additional structure, how many does it admit?
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The abstract classification of high-dimensional manifolds is
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Low dimension manifolds (dimensions 2 and 3) admit geometry.
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works in the middle dimension in dimension 5 and more: two
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Fundamental results in embeddings and immersions include:
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In codimension 0, a codimension 0 (proper) immersion is a
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Thus given two categories, the two natural questions are:
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generically don't intersect in dimension 5 and above, by
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Analogously to the classification of manifolds, in high
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more than 2: when the codimension is 2, one encounters
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Discrete groups in space and uniformization problems
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Manifolds have a rich set of invariants, including:
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Acta Universitatis Carolinae Mathematica et Physica
258:tori, and an invariant that classifies them is the 1450:"On the classification of 1-dimensional manifolds" 1389:One may classify maps up to various equivalences: 1204: 1081:, as every orientable surface can be considered a 928: 886: 840: 803: 761: 723: 687: 632: 557: 525: 493: 466: 389: 250: 171: 134: 2431: 1138: 967:Dimension 0 is trivial and 1 is straightforward. 220: 936:admits a metric with negative Ricci curvature. 585:, so 2-manifolds are classified homologically. 1568: 1528:Princeton University Press eBook Package 2014 606:Manifolds in dimension 4 and above cannot be 172:{\displaystyle {\mbox{Diff}}\to {\mbox{Top}}} 135:{\displaystyle {\mbox{Diff}}\to {\mbox{Top}}} 79:Different categories and additional structure 1265: 958:, all but hyperbolic are quite constrained. 595:): for instance, orientable 3-manifolds are 1271:1-dimensional: homeomorphisms of the circle 228:For instance, for orientable surfaces, the 53:discussion of "low" versus "high" dimension 1575: 1561: 1238: 904:classical theorems in Riemannian geometry 101:and a different classification question. 1582: 1155: 961: 943:), and likewise for zero curvature (the 232:enumerates them as the connected sum of 1168:The reason for dimension 5 is that the 2432: 1447: 1370:Key tools in studying these maps are: 1103: 887:{\displaystyle f'h\sim f\colon N\to M} 1556: 1525: 1478: 1441: 1011: 1502: 1251:. The other question is classifying 1126:exotic differentiable structures on 987:exotic differentiable structures on 70:: given two manifolds (presented as 2450:Mathematical classification systems 1235:. This is discussed further below. 1098:Solution of the PoincarĂ© conjecture 13: 1519: 1330: 1285: 954:Similarly for 3-manifolds: of the 347:Modern algebraic topology (beyond 14: 2461: 1053:Dimensions 2 and 3: geometrizable 202:In more general categories, this 1100:) is analytic, not topological. 568: 215:reduction of the structure group 186:Which manifolds of a given type 104:These categories are related by 1133:generalized PoincarĂ© conjecture 994:generalized PoincarĂ© conjecture 841:{\displaystyle h\colon N\to N'} 1615:Differentiable/Smooth manifold 1487: 1472: 1338:Geometrically interesting are 878: 827: 798: 776: 756: 744: 724:{\displaystyle f\colon N\to M} 715: 682: 670: 573:The Euler characteristic is a 552: 540: 520: 508: 461: 449: 384: 378: 159: 122: 31: 1: 1434: 1218:Geometric topology: Dimension 1139:Dimension 5 and more: surgery 326:, and characteristic numbers) 221:Enumeration versus invariants 209:Many of these structures are 93:is classifying objects up to 400: 7: 2321:Classification of manifolds 1417: 577:invariant, and thus can be 533:is an open manifold, while 36: 26:classification of manifolds 10: 2466: 1510:Bordism of diffeomorphisms 1342:and isometric immersions. 1243:From the point of view of 1220:for details on dimension. 1142: 1107: 1062: 1056: 1015: 908:1/4-pinched sphere theorem 593:complete set of invariants 501:is a closed manifold, and 404: 353:Extraordinary (co)homology 230:classification of surfaces 82: 2397:over commutative algebras 2354: 2313: 2246: 2143: 2039: 1986: 1977: 1813: 1736: 1675: 1595: 1536:10.1515/9781400865192-009 1424:The Berger classification 1355:Whitney immersion theorem 1350:Whitney embedding theorem 1266:Low-dimensional self-maps 1094:geometrization conjecture 390:{\displaystyle MO_{*}(M)} 2113:Riemann curvature tensor 1493:Apanasov, B..  1205:{\displaystyle 2+2<5} 601:low-dimensional topology 190:an additional structure? 1448:FrolĂ­k, Zdeněk (1962). 929:{\displaystyle n\geq 3} 804:{\displaystyle (N',f')} 650:word problem for groups 633:{\displaystyle n\geq 4} 599:(Steenrod's theorem in 474:is a compact manifold, 251:{\displaystyle n\geq 0} 85:Categories of manifolds 1905:Manifold with boundary 1620:Differential structure 1360:Nash embedding theorem 1239:Maps between manifolds 1206: 1165: 1071:uniformization theorem 930: 888: 842: 805: 763: 725: 689: 634: 610:classified: given two 589:Characteristic classes 559: 527: 495: 468: 391: 324:characteristic classes 252: 213:, and the question is 173: 136: 89:Formally, classifying 2440:Differential geometry 1207: 1159: 1143:Further information: 1108:Further information: 1063:Further information: 1057:Further information: 1016:Further information: 962:Overview by dimension 931: 889: 843: 806: 764: 762:{\displaystyle (N,f)} 726: 690: 688:{\displaystyle (N,f)} 635: 560: 558:{\displaystyle [0,1)} 528: 526:{\displaystyle (0,1)} 496: 494:{\displaystyle S^{1}} 469: 405:Further information: 397:) are generally not. 392: 253: 174: 137: 83:Further information: 22:geometry and topology 2052:Covariant derivative 1603:Topological manifold 1384:Calculus of functors 1365:Smale-Hirsch theorem 1233:calculus of functors 1184: 914: 852: 815: 773: 741: 734:homotopy equivalence 703: 667: 663:it classifies pairs 618: 579:effectively computed 537: 505: 478: 446: 362: 334:Reidemeister torsion 297:Euler characteristic 264:Euler characteristic 236: 149: 112: 2086:Exterior derivative 1688:Atiyah–Singer index 1637:Riemannian manifold 1276:mapping class group 1104:Dimension 4: exotic 318:normal invariants ( 2392:Secondary calculus 2346:Singularity theory 2301:Parallel transport 2069:De Rham cohomology 1708:Generalized Stokes 1466:10338.dmlcz/142137 1296:relative dimension 1202: 1166: 1079:algebraic geometry 1059:Surface (topology) 1012:Dimensions 0 and 1 926: 884: 838: 801: 759: 737:, two such pairs, 721: 685: 630: 565:is none of these. 555: 523: 491: 464: 387: 314:Geometric topology 292:algebraic topology 274:Point-set topology 248: 169: 167: 157: 132: 130: 120: 106:forgetful functors 2427: 2426: 2309: 2308: 2074:Differential form 1728:Whitney embedding 1662:Differential form 1545:978-1-4008-6519-2 654:fundamental group 351:theory), such as 302:Fundamental group 166: 156: 129: 119: 2457: 2419:Stratified space 2377:FrĂ©chet manifold 2091:Interior product 1984: 1983: 1681: 1577: 1570: 1563: 1554: 1553: 1549: 1513: 1506: 1500: 1491: 1485: 1484: 1476: 1470: 1469: 1445: 1211: 1209: 1208: 1203: 1178:general position 1075:complex analysis 1028:second countable 941:projective plane 935: 933: 932: 927: 893: 891: 890: 885: 862: 847: 845: 844: 839: 837: 810: 808: 807: 802: 797: 786: 768: 766: 765: 760: 730: 728: 727: 722: 694: 692: 691: 686: 639: 637: 636: 631: 564: 562: 561: 556: 532: 530: 529: 524: 500: 498: 497: 492: 490: 489: 473: 471: 470: 467:{\displaystyle } 465: 422:compact manifold 396: 394: 393: 388: 377: 376: 257: 255: 254: 249: 178: 176: 175: 170: 168: 164: 158: 154: 141: 139: 138: 133: 131: 127: 121: 117: 2465: 2464: 2460: 2459: 2458: 2456: 2455: 2454: 2430: 2429: 2428: 2423: 2362:Banach manifold 2355:Generalizations 2350: 2305: 2242: 2139: 2101:Ricci curvature 2057:Cotangent space 2035: 1973: 1815: 1809: 1768:Exponential map 1732: 1677: 1671: 1591: 1581: 1546: 1522: 1520:Further reading 1517: 1516: 1507: 1503: 1492: 1488: 1477: 1473: 1446: 1442: 1437: 1420: 1333: 1331:High dimensions 1288: 1286:Low codimension 1274:2-dimensional: 1268: 1245:category theory 1241: 1185: 1182: 1181: 1147: 1141: 1112: 1106: 1087:algebraic curve 1083:Riemann surface 1067: 1061: 1055: 1020: 1014: 964: 915: 912: 911: 900: 855: 853: 850: 849: 848:and a homotopy 830: 816: 813: 812: 790: 779: 774: 771: 770: 742: 739: 738: 704: 701: 700: 699:a manifold and 668: 665: 664: 640:) presented as 619: 616: 615: 571: 538: 535: 534: 506: 503: 502: 485: 481: 479: 476: 475: 447: 444: 443: 429:closed manifold 409: 407:closed manifold 403: 372: 368: 363: 360: 359: 330:Simple homotopy 307:Cohomology ring 237: 234: 233: 223: 162: 152: 150: 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1795:Lie derivative 1792: 1790:Integral curve 1787: 1782: 1777: 1776: 1775: 1765: 1760: 1759: 1758: 1751:Diffeomorphism 1748: 1742: 1740: 1734: 1733: 1731: 1730: 1725: 1720: 1715: 1710: 1705: 1700: 1695: 1690: 1684: 1682: 1673: 1672: 1670: 1669: 1664: 1659: 1654: 1649: 1644: 1639: 1634: 1629: 1628: 1627: 1622: 1612: 1611: 1610: 1599: 1597: 1596:Basic concepts 1593: 1592: 1580: 1579: 1572: 1565: 1557: 1551: 1550: 1544: 1521: 1518: 1515: 1514: 1501: 1486: 1471: 1439: 1438: 1436: 1433: 1432: 1431: 1419: 1416: 1412: 1411: 1406: 1401: 1396: 1387: 1386: 1381: 1368: 1367: 1362: 1357: 1352: 1332: 1329: 1328: 1327: 1324: 1321:covering space 1317: 1314: 1307: 1287: 1284: 1283: 1282: 1272: 1267: 1264: 1240: 1237: 1214:Casson handles 1201: 1198: 1195: 1192: 1189: 1151:surgery theory 1145:surgery theory 1140: 1137: 1105: 1102: 1054: 1051: 1050: 1049: 1042: 1013: 1010: 982: 981: 978:surgery theory 974: 971: 968: 963: 960: 925: 922: 919: 899: 896: 883: 880: 877: 874: 871: 868: 865: 861: 858: 836: 833: 829: 826: 823: 820: 800: 796: 793: 789: 785: 782: 778: 758: 755: 752: 749: 746: 720: 717: 714: 711: 708: 684: 681: 678: 675: 672: 629: 626: 623: 597:parallelizable 570: 567: 554: 551: 548: 545: 542: 522: 519: 516: 513: 510: 488: 484: 463: 460: 457: 454: 451: 442:For instance, 440: 439: 432: 425: 402: 399: 386: 383: 380: 375: 371: 367: 345: 344: 343: 342: 340:Surgery theory 337: 327: 311: 310: 309: 304: 299: 288: 287: 286: 281: 247: 244: 241: 222: 219: 200: 199: 195: 194: 191: 161: 124: 80: 77: 76: 75: 64: 61: 57: 56: 48: 47: 44:surgery theory 38: 35: 33: 30: 9: 6: 4: 3: 2: 2462: 2451: 2448: 2446: 2443: 2441: 2438: 2437: 2435: 2420: 2417: 2415: 2414:Supermanifold 2412: 2410: 2407: 2405: 2402: 2398: 2395: 2394: 2393: 2390: 2388: 2385: 2383: 2380: 2378: 2375: 2373: 2370: 2368: 2365: 2363: 2360: 2359: 2357: 2353: 2347: 2344: 2342: 2339: 2337: 2334: 2332: 2329: 2327: 2324: 2322: 2319: 2318: 2316: 2312: 2302: 2299: 2297: 2294: 2292: 2289: 2287: 2284: 2282: 2279: 2277: 2274: 2272: 2269: 2267: 2264: 2262: 2259: 2257: 2254: 2253: 2251: 2249: 2245: 2239: 2236: 2234: 2231: 2229: 2226: 2224: 2221: 2219: 2216: 2214: 2211: 2209: 2205: 2201: 2199: 2196: 2194: 2191: 2189: 2185: 2181: 2179: 2176: 2174: 2171: 2169: 2166: 2164: 2161: 2159: 2156: 2154: 2151: 2150: 2148: 2146: 2142: 2136: 2135:Wedge product 2133: 2131: 2128: 2124: 2121: 2120: 2119: 2116: 2114: 2111: 2107: 2104: 2103: 2102: 2099: 2097: 2094: 2092: 2089: 2087: 2084: 2080: 2079:Vector-valued 2077: 2076: 2075: 2072: 2070: 2067: 2063: 2060: 2059: 2058: 2055: 2053: 2050: 2048: 2045: 2044: 2042: 2038: 2032: 2029: 2027: 2024: 2022: 2019: 2015: 2012: 2011: 2010: 2009:Tangent space 2007: 2005: 2002: 2000: 1997: 1995: 1992: 1991: 1989: 1985: 1982: 1980: 1976: 1970: 1967: 1965: 1961: 1957: 1955: 1952: 1950: 1946: 1942: 1938: 1936: 1933: 1931: 1928: 1926: 1923: 1921: 1918: 1916: 1913: 1911: 1908: 1906: 1903: 1899: 1896: 1895: 1894: 1891: 1889: 1886: 1884: 1881: 1879: 1876: 1874: 1871: 1869: 1866: 1864: 1861: 1859: 1856: 1854: 1851: 1849: 1846: 1844: 1840: 1836: 1834: 1830: 1826: 1824: 1821: 1820: 1818: 1812: 1806: 1803: 1801: 1798: 1796: 1793: 1791: 1788: 1786: 1783: 1781: 1778: 1774: 1773:in Lie theory 1771: 1770: 1769: 1766: 1764: 1761: 1757: 1754: 1753: 1752: 1749: 1747: 1744: 1743: 1741: 1739: 1735: 1729: 1726: 1724: 1721: 1719: 1716: 1714: 1711: 1709: 1706: 1704: 1701: 1699: 1696: 1694: 1691: 1689: 1686: 1685: 1683: 1680: 1676:Main results 1674: 1668: 1665: 1663: 1660: 1658: 1657:Tangent space 1655: 1653: 1650: 1648: 1645: 1643: 1640: 1638: 1635: 1633: 1630: 1626: 1623: 1621: 1618: 1617: 1616: 1613: 1609: 1606: 1605: 1604: 1601: 1600: 1598: 1594: 1589: 1585: 1578: 1573: 1571: 1566: 1564: 1559: 1558: 1555: 1547: 1541: 1537: 1533: 1529: 1524: 1523: 1511: 1505: 1498: 1497: 1490: 1482: 1475: 1467: 1463: 1459: 1455: 1451: 1444: 1440: 1429: 1425: 1422: 1421: 1415: 1410: 1407: 1405: 1402: 1400: 1397: 1395: 1392: 1391: 1390: 1385: 1382: 1380: 1378: 1373: 1372: 1371: 1366: 1363: 1361: 1358: 1356: 1353: 1351: 1348: 1347: 1346: 1343: 1341: 1336: 1325: 1322: 1318: 1315: 1312: 1308: 1305: 1304: 1303: 1301: 1297: 1293: 1281: 1280:Torelli group 1277: 1273: 1270: 1269: 1263: 1261: 1256: 1254: 1250: 1246: 1236: 1234: 1230: 1226: 1221: 1219: 1215: 1199: 1196: 1193: 1190: 1187: 1179: 1175: 1174:Whitney disks 1171: 1170:Whitney trick 1163: 1162:Whitney trick 1158: 1154: 1152: 1146: 1136: 1134: 1130: 1129: 1122: 1120: 1119:topologically 1115: 1111: 1101: 1099: 1095: 1090: 1088: 1084: 1080: 1076: 1072: 1066: 1060: 1047: 1043: 1040: 1039: 1038: 1035: 1033: 1029: 1024: 1019: 1009: 1006: 1001: 997: 995: 991: 990: 979: 975: 972: 969: 966: 965: 959: 957: 952: 950: 946: 942: 937: 923: 920: 917: 909: 905: 895: 881: 875: 872: 869: 866: 863: 859: 856: 834: 831: 824: 821: 818: 794: 791: 787: 783: 780: 753: 750: 747: 736: 735: 718: 712: 709: 706: 698: 679: 676: 673: 662: 657: 655: 651: 647: 643: 627: 624: 621: 613: 609: 604: 602: 598: 594: 590: 586: 584: 580: 576: 569:Computability 566: 549: 546: 543: 517: 514: 511: 486: 482: 458: 455: 452: 437: 436:open manifold 433: 430: 426: 423: 419: 418: 417: 413: 408: 398: 381: 373: 369: 365: 356: 354: 350: 341: 338: 335: 331: 328: 325: 321: 320:orientability 317: 316: 315: 312: 308: 305: 303: 300: 298: 295: 294: 293: 289: 285: 284:Connectedness 282: 280: 277: 276: 275: 272: 271: 270: 267: 265: 261: 245: 242: 239: 231: 226: 218: 216: 212: 207: 205: 204:structure set 197: 196: 192: 189: 185: 184: 183: 180: 143: 107: 102: 100: 96: 92: 86: 73: 69: 65: 62: 59: 58: 54: 50: 49: 45: 41: 40: 29: 27: 23: 19: 2341:Moving frame 2336:Morse theory 2326:Gauge theory 2320: 2118:Tensor field 2047:Closed/Exact 2026:Vector field 1994:Distribution 1935:Hypercomplex 1930:Quaternionic 1667:Vector field 1625:Smooth atlas 1527: 1504: 1494: 1489: 1480: 1474: 1457: 1453: 1443: 1413: 1388: 1376: 1369: 1344: 1337: 1334: 1291: 1289: 1257: 1252: 1248: 1242: 1222: 1167: 1148: 1127: 1123: 1118: 1116: 1113: 1091: 1068: 1036: 1025: 1021: 1004: 1002: 998: 988: 983: 956:8 geometries 953: 949:Klein bottle 938: 901: 732: 696: 660: 658: 646:handlebodies 642:CW complexes 614:-manifolds ( 611: 605: 587: 583:CW structure 572: 441: 435: 428: 421: 414: 410: 357: 346: 268: 227: 224: 211:G-structures 208: 203: 201: 187: 181: 144: 103: 88: 72:CW complexes 25: 15: 2286:Levi-Civita 2276:Generalized 2248:Connections 2198:Lie algebra 2130:Volume form 2031:Vector flow 2004:Pushforward 1999:Lie bracket 1898:Lie algebra 1863:G-structure 1652:Pushforward 1632:Submanifold 1404:concordance 1379:-principles 1311:knot theory 1300:knot theory 1260:codimension 1229:knot theory 1225:codimension 1085:or complex 1046:knot theory 608:effectively 575:homological 279:Compactness 95:isomorphism 68:ineffective 32:Main themes 18:mathematics 2434:Categories 2409:Stratifold 2367:Diffeology 2163:Associated 1964:Symplectic 1949:Riemannian 1878:Hyperbolic 1805:Submersion 1713:Hopf–Rinow 1647:Submersion 1642:Smooth map 1508:M. Kreck, 1460:(1): 1–4. 1435:References 1340:isometries 1110:4-manifold 1065:3-manifold 2445:Manifolds 2291:Principal 2266:Ehresmann 2223:Subbundle 2213:Principal 2188:Fibration 2168:Cotangent 2040:Covectors 1893:Lie group 1873:Hermitian 1816:manifolds 1785:Immersion 1780:Foliation 1718:Noether's 1703:Frobenius 1698:De Rham's 1693:Darboux's 1584:Manifolds 1399:cobordism 1374:Gromov's 1032:long line 921:≥ 879:→ 873:: 867:∼ 828:→ 822:: 716:→ 710:: 625:≥ 401:Point-set 374:∗ 349:cobordism 243:≥ 160:→ 123:→ 91:manifolds 2387:Orbifold 2382:K-theory 2372:Diffiety 2096:Pullback 1910:Oriented 1888:Kenmotsu 1868:Hadamard 1814:Types of 1763:Geodesic 1588:Glossary 1428:holonomy 1418:See also 1394:homotopy 947:and the 860:′ 835:′ 795:′ 784:′ 581:given a 290:Classic 99:category 37:Overview 2331:History 2314:Related 2228:Tangent 2206:)  2186:)  2153:Adjoint 2145:Bundles 2123:density 2021:Torsion 1987:Vectors 1979:Tensors 1962:)  1947:)  1943:,  1941:Pseudo− 1920:Poisson 1853:Finsler 1848:Fibered 1843:Contact 1841:)  1833:Complex 1831:)  1800:Section 1430:groups. 1409:isotopy 1249:objects 1005:predict 2296:Vector 2281:Koszul 2261:Cartan 2256:Affine 2238:Vector 2233:Tensor 2218:Spinor 2208:Normal 2204:Stable 2158:Affine 2062:bundle 2014:bundle 1960:Almost 1883:KĂ€hler 1839:Almost 1829:Almost 1823:Closed 1723:Sard's 1679:(list) 1542:  1117:Since 24:, the 2404:Sheaf 2178:Fiber 1954:Rizza 1925:Prime 1756:Local 1746:Curve 1608:Atlas 1018:Curve 945:torus 902:Many 695:with 260:genus 188:admit 2271:Form 2173:Dual 2106:flow 1969:Tame 1945:Sub− 1858:Flat 1738:Maps 1540:ISBN 1278:and 1253:maps 1197:< 1160:The 1077:and 769:and 155:Diff 118:Diff 2193:Jet 1532:doi 1462:hdl 1426:of 1302:). 1262:". 644:or 434:An 262:or 165:Top 128:Top 16:In 2436:: 2184:Co 1538:. 1456:. 1452:. 1292:co 1153:. 1135:. 996:. 894:. 731:a 427:A 420:A 322:, 266:. 142:. 2202:( 2182:( 1958:( 1939:( 1837:( 1827:( 1590:) 1586:( 1576:e 1569:t 1562:v 1548:. 1534:: 1468:. 1464:: 1458:3 1377:h 1313:. 1200:5 1194:2 1191:+ 1188:2 1180:( 1128:R 1048:. 989:R 980:. 924:3 918:n 882:M 876:N 870:f 864:h 857:f 832:N 825:N 819:h 799:) 792:f 788:, 781:N 777:( 757:) 754:f 751:, 748:N 745:( 719:M 713:N 707:f 697:N 683:) 680:f 677:, 674:N 671:( 661:M 628:4 622:n 612:n 553:) 550:1 547:, 544:0 541:[ 521:) 518:1 515:, 512:0 509:( 487:1 483:S 462:] 459:1 456:, 453:0 450:[ 385:) 382:M 379:( 370:O 366:M 336:) 332:( 246:0 240:n 55:. 46:.

Index

mathematics
geometry and topology
surgery theory
discussion of "low" versus "high" dimension
ineffective
CW complexes
Categories of manifolds
manifolds
isomorphism
category
forgetful functors
G-structures
reduction of the structure group
classification of surfaces
genus
Euler characteristic
Point-set topology
Compactness
Connectedness
algebraic topology
Euler characteristic
Fundamental group
Cohomology ring
Geometric topology
orientability
characteristic classes
Simple homotopy
Reidemeister torsion
Surgery theory
cobordism

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