Knowledge (XXG)

Homotopy principle

Source đź“ť

28: 884: 876:
A non-holonomic solution to this relation would consist in the data of two functions, a differentiable function f(x), and a continuous function g(x), with g(x) nowhere vanishing. A holonomic solution gives rise to a non-holonomic solution by taking g(x) = f'(x). The space of non-holonomic solutions
791:
into a holonomic one in the class of non-holonomic solutions. Thus in the presence of h-principle, a differential topological problem reduces to an algebraic topological problem. More explicitly this means that apart from the topological obstruction there is no other obstruction to the existence of a
1152:
to holonomic ones but also can be arbitrarily well approximated by the holonomic ones (by going back and forth, like parallel parking in a limited space) – note that this approximates both the position and the angle of the car arbitrarily closely. This implies that, theoretically, it is possible to
799:
Many underdetermined partial differential equations satisfy the h-principle. However, the falsity of an h-principle is also an interesting statement, intuitively this means the objects being studied have non-trivial geometry that cannot be reduced to topology. As an example, embedded
969:
in complex numbers). Note that here there are no immersions of order 0, as those would need to turn back on themselves. Extending this to circles immersed in the plane – the immersion condition is precisely the condition that the derivative does not vanish – the
779:
In order to check whether a solution to our original equation exists, one can first check if there is a non-holonomic solution. Usually this is quite easy, and if there is no non-holonomic solution, then our original equation did not have any solutions.
632: 868:
A holonomic solution to this relation is a function whose derivative is nowhere vanishing, i.e. a strictly monotone differentiable function, either increasing or decreasing. The space of such functions consists of two disjoint
763: 529: 1346:-embedding (respectively, immersion). This is also a dense h-principle, and can be proven by an essentially similar "wrinkling" – or rather, circling – technique to the car in the plane, though it is much more involved. 997:
which requires the partial derivatives in each direction to not vanish and to be linearly independent, and the resulting analog of the Gauss map is a map to the Stiefel manifold, or more generally between frame bundles.
1132: 264: 1547: 169: 401: 934: 1317: 859: 1700: 967: 1148:
A non-holonomic solution in this case, roughly speaking, corresponds to a motion of the car by sliding in the plane. In this case the non-holonomic solutions are not only
1255: 339: 299: 1488: 1452: 1064: 1887: 1851: 1785: 1758: 1727: 1671: 1644: 1610: 1583: 1419: 1344: 1282: 1209: 1178: 1508: 1044: 1024: 540: 1898:
David Spring, Convex integration theory - solutions to the h-principle in geometry and topology, Monographs in Mathematics 92, Birkhauser-Verlag, 1998
643: 409: 1006:
As another simple example, consider a car moving in the plane. The position of a car in the plane is determined by three parameters: two coordinates
2028: 993:
are much further-reaching generalizations, and much more involved, but similar in principle – immersion requires the derivative to have rank
899:
This trivial example has nontrivial generalizations: extending this to immersions of a circle into itself classifies them by order (or
1968: 1946: 1072: 2033: 177: 1956: 71: 971: 888: 79: 1153:
parallel park in any space longer than the length of your car. It also implies that, in a contact 3 manifold, any curve is
52: 1729:
because a small oscillating sphere would provide a large lower bound for the principal curvatures, and therefore for the
56: 27: 1513: 989:, and Hirsch's generalization of this to immersions of manifolds being classified as homotopy classes of maps of 907:
and applying the above analysis to the resulting monotone map – the linear map corresponds to multiplying angle:
109: 904: 804:
in a symplectic manifold do not satisfy an h-principle, to prove this one needs to find invariants coming from
344: 1223: 910: 805: 63:
PDEs or PDRs, such as the immersion problem, isometric immersion problem, fluid dynamics, and other areas.
1219: 1142: 801: 60: 1287: 74:
and Anthony V. Phillips. It was based on earlier results that reduced partial differential relations to
1676: 1046:
for the location (a good choice is the location of the midpoint between the back wheels) and an angle
1817:
S. Smale, The classification of immersions of spheres in Euclidean spaces. Ann. of Math(2) 69 (1959)
939: 1616: 796:
is much easier to handle and can be addressed with the obstruction theory for topological bundles.
824: 1995: 1233: 1552:
Any open manifold admits a (non-complete) Riemannian metric of positive (or negative) curvature.
1370:
Here we list a few counter-intuitive results which can be proved by applying the h-principle:
312: 272: 1964: 1942: 1788: 1457: 883: 1424: 1049: 2005: 986: 67: 1865: 1829: 1763: 1736: 1705: 1649: 1622: 1588: 1561: 1397: 1322: 1260: 1187: 1156: 1730: 1555: 1181: 32: 1066:
which describes the orientation of the car. The motion of the car satisfies the equation
880:
Thus the inclusion of holonomic into non-holonomic solutions satisfies the h-principle.
877:
again consists of two disjoint convex sets, according as g(x) is positive or negative.
627:{\displaystyle y_{j}={\partial ^{k}f \over \partial u_{j_{1}}\ldots \partial u_{j_{k}}}.} 982:
and showing that this satisfies an h-principle; here again order 0 is more complicated.
873:: the increasing ones and the decreasing ones, and has the homotopy type of two points. 821:
Perhaps the simplest partial differential relation is for the derivative to not vanish:
1493: 1029: 1009: 975: 900: 892: 891:
shows that immersions of the circle in the plane satisfy an h-principle, expressed by
772:, and a solution of the system which is also solution of our original PDE is called a 2022: 1184:
curve. This last property is stronger than the general h-principle; it is called the
2010: 1979: 990: 1932: 1924: 78:, particularly for immersions. The first evidence of h-principle appeared in the 758:{\displaystyle \Psi _{}^{}(u_{1},u_{2},\dots ,u_{m},y_{1},y_{2},\dots ,y_{N})=0} 524:{\displaystyle \Psi _{}^{}(u_{1},u_{2},\dots ,u_{m},y_{1},y_{2},\dots ,y_{N})=0} 40: 870: 1227: 1149: 979: 17: 1760:
this has to be equal to 1 everywhere, the Gauss curvature of the standard
985:
Smale's classification of immersions of spheres as the homotopy groups of
1889:
Isometric Imbeddings I, II. Nederl. Acad. Wetensch. Proc. Ser A 58 (1955)
1138: 788: 75: 1808:
M. W. Hirsch, Immersions of manifold. Trans. Amer. Math. Soc. 93 (1959)
1137:
since a non-skidding car must move in the direction of its wheels. In
1355:
Removal of Singularities technique developed by Gromov and Eliashberg
31:
The homotopy principle generalizes such results as Smale's proof of
2000: 1733:
of the immersed sphere, but on the other hand if the immersion is
882: 26: 1394:|. Then there is a continuous one-parameter family of functions 1319:
or larger can be arbitrarily well approximated by an isometric
865:
differential relation, as this is a function in one variable.
1127:{\displaystyle {\dot {x}}\sin \alpha ={\dot {y}}\cos \alpha .} 1909:
Mathematical Omnibus: Thirty Lectures on Classic Mathematics
259:{\displaystyle \Psi (u_{1},u_{2},\dots ,u_{m},J_{f}^{k})=0} 102:
which satisfies a partial differential equation of degree
86:
embedding theorem and the Smale–Hirsch immersion theorem.
792:
holonomic solution. The topological problem of finding a
403:
Then our original equation can be thought as a system of
1361:
Convex integration based on the work of Nash and Kuiper.
1358:
Sheaf technique based on the work of Smale and Hirsch.
1868: 1832: 1766: 1739: 1708: 1679: 1652: 1625: 1591: 1564: 1516: 1496: 1460: 1427: 1400: 1325: 1290: 1263: 1236: 1190: 1159: 1075: 1052: 1032: 1012: 942: 913: 827: 646: 543: 412: 347: 315: 275: 180: 112: 1978:
De Lellis, Camillo; Székelyhidi, László Jr. (2012).
534:and some number of equations of the following type 1881: 1845: 1779: 1752: 1721: 1694: 1665: 1638: 1604: 1577: 1541: 1502: 1482: 1446: 1413: 1338: 1311: 1276: 1249: 1203: 1172: 1126: 1058: 1038: 1018: 961: 928: 853: 757: 626: 523: 395: 333: 293: 258: 163: 1931:Eliashberg, Y.; Mishachev, N.; Ariki, S. (2002). 82:. This was followed by the Nash–Kuiper isometric 1984:-principle and the equations of fluid dynamics" 1853:Isometric Imbedding. Ann. of Math(2) 60 (1954) 1558:without creasing or tearing can be done using 1218:While this example is simple, compare to the 8: 1542:{\displaystyle \operatorname {grad} (f_{t})} 1141:terms, not all paths in the task space are 164:{\displaystyle (u_{1},u_{2},\dots ,u_{m})} 2009: 1999: 1873: 1867: 1837: 1831: 1771: 1765: 1744: 1738: 1713: 1707: 1686: 1682: 1681: 1678: 1657: 1651: 1630: 1624: 1617:Nash-Kuiper C isometric embedding theorem 1596: 1590: 1569: 1563: 1530: 1515: 1495: 1465: 1459: 1432: 1426: 1405: 1399: 1330: 1324: 1297: 1292: 1289: 1268: 1262: 1241: 1235: 1195: 1189: 1164: 1158: 1101: 1100: 1077: 1076: 1074: 1051: 1031: 1011: 978:by considering the homotopy class of the 953: 941: 912: 826: 740: 721: 708: 695: 676: 663: 653: 651: 645: 610: 605: 587: 582: 564: 557: 548: 542: 506: 487: 474: 461: 442: 429: 419: 417: 411: 396:{\displaystyle y_{1},y_{2},\dots ,y_{N}.} 384: 365: 352: 346: 325: 320: 314: 285: 280: 274: 241: 236: 223: 204: 191: 179: 152: 133: 120: 111: 1619:, in particular implies that there is a 1801: 929:{\displaystyle \theta \mapsto n\theta } 301:stands for all partial derivatives of 787:if any non-holonomic solution can be 59:(PDRs). The h-principle is good for 7: 309:. Let us exchange every variable in 1673:into an arbitrarily small ball of 1374:Cone eversion. Consider functions 1312:{\displaystyle \mathbf {R} ^{m+1}} 1242: 648: 598: 575: 561: 414: 181: 94:Assume we want to find a function 25: 1941:. American Mathematical Society. 1646:isometric immersion of the round 51:) is a very general way to solve 1695:{\displaystyle \mathbb {R} ^{3}} 1293: 2011:10.1090/S0273-0979-2012-01376-9 2029:Partial differential equations 1961:Partial differential relations 1536: 1523: 962:{\displaystyle z\mapsto z^{n}} 946: 917: 842: 836: 746: 656: 512: 422: 341:for new independent variables 247: 184: 158: 113: 57:partial differential relations 53:partial differential equations 1: 1350:Ways to prove the h-principle 903:), by lifting the map to the 1257:) embedding or immersion of 854:{\displaystyle f'(x)\neq 0.} 1702:. This immersion cannot be 1250:{\displaystyle C^{\infty }} 55:(PDEs), and more generally 2050: 1907:D. Fuchs, S. Tabachnikov, 66:The theory was started by 1927:, translation Kiki Hudson 1925:Embeddings and immersions 1549:is not zero at any point. 972:Whitney–Graustein theorem 889:Whitney–Graustein theorem 806:pseudo-holomorphic curves 785:satisfies the h-principle 334:{\displaystyle J_{f}^{k}} 294:{\displaystyle J_{f}^{k}} 80:Whitney–Graustein theorem 1483:{\displaystyle f_{1}=-f} 905:universal covering space 171:. One can rewrite it as 2034:Mathematical principles 1447:{\displaystyle f_{0}=f} 1059:{\displaystyle \alpha } 1883: 1847: 1781: 1754: 1723: 1696: 1667: 1640: 1606: 1579: 1543: 1504: 1484: 1448: 1415: 1340: 1313: 1278: 1251: 1226:, which says that any 1220:Nash embedding theorem 1205: 1174: 1128: 1060: 1040: 1020: 963: 930: 896: 855: 794:non-holonomic solution 770:non-holonomic solution 759: 628: 525: 397: 335: 295: 260: 165: 36: 1988:Bull. Amer. Math. Soc 1884: 1882:{\displaystyle C^{1}} 1848: 1846:{\displaystyle C^{1}} 1782: 1780:{\displaystyle S^{2}} 1755: 1753:{\displaystyle C^{2}} 1724: 1722:{\displaystyle C^{2}} 1697: 1668: 1666:{\displaystyle S^{2}} 1641: 1639:{\displaystyle C^{1}} 1607: 1605:{\displaystyle S^{2}} 1580: 1578:{\displaystyle C^{1}} 1544: 1505: 1485: 1449: 1416: 1414:{\displaystyle f_{t}} 1341: 1339:{\displaystyle C^{1}} 1314: 1279: 1277:{\displaystyle M^{m}} 1252: 1206: 1204:{\displaystyle C^{0}} 1175: 1173:{\displaystyle C^{0}} 1129: 1061: 1041: 1021: 964: 931: 886: 861:Properly, this is an 856: 760: 629: 526: 398: 336: 296: 261: 166: 30: 1934:Introduction to the 1866: 1830: 1764: 1737: 1706: 1677: 1650: 1623: 1589: 1562: 1514: 1494: 1458: 1425: 1398: 1323: 1288: 1261: 1234: 1188: 1157: 1073: 1050: 1030: 1010: 974:classified these by 940: 911: 825: 644: 541: 410: 345: 313: 273: 178: 110: 1224:Nash–Kuiper theorem 1222:, specifically the 655: 421: 330: 290: 246: 1879: 1843: 1777: 1750: 1719: 1692: 1663: 1636: 1602: 1575: 1539: 1500: 1480: 1444: 1411: 1336: 1309: 1274: 1247: 1201: 1170: 1124: 1056: 1036: 1016: 1002:A car in the plane 959: 926: 897: 851: 817:Monotone functions 774:holonomic solution 755: 647: 624: 521: 413: 393: 331: 316: 291: 276: 256: 232: 161: 106:, in co-ordinates 45:homotopy principle 37: 1923:Masahisa Adachi, 1789:Theorema Egregium 1503:{\displaystyle t} 1213:dense h-principle 1109: 1085: 1039:{\displaystyle y} 1019:{\displaystyle x} 987:Stiefel manifolds 619: 305:up to order  16:(Redirected from 2041: 2015: 2013: 2003: 1974: 1952: 1911: 1905: 1899: 1896: 1890: 1888: 1886: 1885: 1880: 1878: 1877: 1860: 1854: 1852: 1850: 1849: 1844: 1842: 1841: 1824: 1818: 1815: 1809: 1806: 1786: 1784: 1783: 1778: 1776: 1775: 1759: 1757: 1756: 1751: 1749: 1748: 1728: 1726: 1725: 1720: 1718: 1717: 1701: 1699: 1698: 1693: 1691: 1690: 1685: 1672: 1670: 1669: 1664: 1662: 1661: 1645: 1643: 1642: 1637: 1635: 1634: 1611: 1609: 1608: 1603: 1601: 1600: 1584: 1582: 1581: 1576: 1574: 1573: 1548: 1546: 1545: 1540: 1535: 1534: 1509: 1507: 1506: 1501: 1489: 1487: 1486: 1481: 1470: 1469: 1453: 1451: 1450: 1445: 1437: 1436: 1420: 1418: 1417: 1412: 1410: 1409: 1345: 1343: 1342: 1337: 1335: 1334: 1318: 1316: 1315: 1310: 1308: 1307: 1296: 1283: 1281: 1280: 1275: 1273: 1272: 1256: 1254: 1253: 1248: 1246: 1245: 1210: 1208: 1207: 1202: 1200: 1199: 1179: 1177: 1176: 1171: 1169: 1168: 1133: 1131: 1130: 1125: 1111: 1110: 1102: 1087: 1086: 1078: 1065: 1063: 1062: 1057: 1045: 1043: 1042: 1037: 1025: 1023: 1022: 1017: 968: 966: 965: 960: 958: 957: 935: 933: 932: 927: 860: 858: 857: 852: 835: 764: 762: 761: 756: 745: 744: 726: 725: 713: 712: 700: 699: 681: 680: 668: 667: 654: 652: 633: 631: 630: 625: 620: 618: 617: 616: 615: 614: 594: 593: 592: 591: 573: 569: 568: 558: 553: 552: 530: 528: 527: 522: 511: 510: 492: 491: 479: 478: 466: 465: 447: 446: 434: 433: 420: 418: 402: 400: 399: 394: 389: 388: 370: 369: 357: 356: 340: 338: 337: 332: 329: 324: 300: 298: 297: 292: 289: 284: 265: 263: 262: 257: 245: 240: 228: 227: 209: 208: 196: 195: 170: 168: 167: 162: 157: 156: 138: 137: 125: 124: 68:Yakov Eliashberg 21: 2049: 2048: 2044: 2043: 2042: 2040: 2039: 2038: 2019: 2018: 1977: 1971: 1955: 1949: 1930: 1920: 1918:Further reading 1915: 1914: 1906: 1902: 1897: 1893: 1869: 1864: 1863: 1861: 1857: 1833: 1828: 1827: 1825: 1821: 1816: 1812: 1807: 1803: 1798: 1767: 1762: 1761: 1740: 1735: 1734: 1731:Gauss curvature 1709: 1704: 1703: 1680: 1675: 1674: 1653: 1648: 1647: 1626: 1621: 1620: 1592: 1587: 1586: 1565: 1560: 1559: 1556:Sphere eversion 1526: 1512: 1511: 1492: 1491: 1461: 1456: 1455: 1428: 1423: 1422: 1401: 1396: 1395: 1390:) = | 1382:without origin 1368: 1352: 1326: 1321: 1320: 1291: 1286: 1285: 1264: 1259: 1258: 1237: 1232: 1231: 1191: 1186: 1185: 1160: 1155: 1154: 1071: 1070: 1048: 1047: 1028: 1027: 1008: 1007: 1004: 949: 938: 937: 909: 908: 828: 823: 822: 819: 814: 812:Simple examples 736: 717: 704: 691: 672: 659: 642: 641: 606: 601: 583: 578: 574: 560: 559: 544: 539: 538: 502: 483: 470: 457: 438: 425: 408: 407: 380: 361: 348: 343: 342: 311: 310: 271: 270: 219: 200: 187: 176: 175: 148: 129: 116: 108: 107: 92: 61:underdetermined 33:sphere eversion 23: 22: 15: 12: 11: 5: 2047: 2045: 2037: 2036: 2031: 2021: 2020: 2017: 2016: 1975: 1969: 1953: 1947: 1928: 1919: 1916: 1913: 1912: 1900: 1891: 1876: 1872: 1862:N. Kuiper, On 1855: 1840: 1836: 1819: 1810: 1800: 1799: 1797: 1794: 1793: 1792: 1774: 1770: 1747: 1743: 1716: 1712: 1689: 1684: 1660: 1656: 1633: 1629: 1613: 1599: 1595: 1585:immersions of 1572: 1568: 1553: 1550: 1538: 1533: 1529: 1525: 1522: 1519: 1499: 1479: 1476: 1473: 1468: 1464: 1443: 1440: 1435: 1431: 1408: 1404: 1367: 1366:Some paradoxes 1364: 1363: 1362: 1359: 1356: 1351: 1348: 1333: 1329: 1306: 1303: 1300: 1295: 1271: 1267: 1244: 1240: 1198: 1194: 1167: 1163: 1135: 1134: 1123: 1120: 1117: 1114: 1108: 1105: 1099: 1096: 1093: 1090: 1084: 1081: 1055: 1035: 1015: 1003: 1000: 976:turning number 956: 952: 948: 945: 925: 922: 919: 916: 901:winding number 893:turning number 850: 847: 844: 841: 838: 834: 831: 818: 815: 813: 810: 766: 765: 754: 751: 748: 743: 739: 735: 732: 729: 724: 720: 716: 711: 707: 703: 698: 694: 690: 687: 684: 679: 675: 671: 666: 662: 658: 650: 637:A solution of 635: 634: 623: 613: 609: 604: 600: 597: 590: 586: 581: 577: 572: 567: 563: 556: 551: 547: 532: 531: 520: 517: 514: 509: 505: 501: 498: 495: 490: 486: 482: 477: 473: 469: 464: 460: 456: 453: 450: 445: 441: 437: 432: 428: 424: 416: 392: 387: 383: 379: 376: 373: 368: 364: 360: 355: 351: 328: 323: 319: 288: 283: 279: 267: 266: 255: 252: 249: 244: 239: 235: 231: 226: 222: 218: 215: 212: 207: 203: 199: 194: 190: 186: 183: 160: 155: 151: 147: 144: 141: 136: 132: 128: 123: 119: 115: 91: 88: 72:Mikhail Gromov 24: 14: 13: 10: 9: 6: 4: 3: 2: 2046: 2035: 2032: 2030: 2027: 2026: 2024: 2012: 2007: 2002: 1997: 1993: 1989: 1985: 1983: 1976: 1972: 1970:3-540-12177-3 1966: 1962: 1958: 1954: 1950: 1948:9780821832271 1944: 1940: 1939: 1935: 1929: 1926: 1922: 1921: 1917: 1910: 1904: 1901: 1895: 1892: 1874: 1870: 1859: 1856: 1838: 1834: 1823: 1820: 1814: 1811: 1805: 1802: 1795: 1790: 1772: 1768: 1745: 1741: 1732: 1714: 1710: 1687: 1658: 1654: 1631: 1627: 1618: 1614: 1597: 1593: 1570: 1566: 1557: 1554: 1551: 1531: 1527: 1520: 1517: 1497: 1477: 1474: 1471: 1466: 1462: 1441: 1438: 1433: 1429: 1406: 1402: 1393: 1389: 1385: 1381: 1377: 1373: 1372: 1371: 1365: 1360: 1357: 1354: 1353: 1349: 1347: 1331: 1327: 1304: 1301: 1298: 1269: 1265: 1238: 1229: 1225: 1221: 1216: 1214: 1196: 1192: 1183: 1165: 1161: 1151: 1146: 1144: 1140: 1121: 1118: 1115: 1112: 1106: 1103: 1097: 1094: 1091: 1088: 1082: 1079: 1069: 1068: 1067: 1053: 1033: 1013: 1001: 999: 996: 992: 991:frame bundles 988: 983: 981: 977: 973: 954: 950: 943: 923: 920: 914: 906: 902: 894: 890: 885: 881: 878: 874: 872: 866: 864: 848: 845: 839: 832: 829: 816: 811: 809: 807: 803: 797: 795: 790: 786: 781: 777: 775: 771: 752: 749: 741: 737: 733: 730: 727: 722: 718: 714: 709: 705: 701: 696: 692: 688: 685: 682: 677: 673: 669: 664: 660: 640: 639: 638: 621: 611: 607: 602: 595: 588: 584: 579: 570: 565: 554: 549: 545: 537: 536: 535: 518: 515: 507: 503: 499: 496: 493: 488: 484: 480: 475: 471: 467: 462: 458: 454: 451: 448: 443: 439: 435: 430: 426: 406: 405: 404: 390: 385: 381: 377: 374: 371: 366: 362: 358: 353: 349: 326: 321: 317: 308: 304: 286: 281: 277: 253: 250: 242: 237: 233: 229: 224: 220: 216: 213: 210: 205: 201: 197: 192: 188: 174: 173: 172: 153: 149: 145: 142: 139: 134: 130: 126: 121: 117: 105: 101: 97: 89: 87: 85: 81: 77: 73: 69: 64: 62: 58: 54: 50: 46: 42: 34: 29: 19: 1991: 1987: 1981: 1963:. Springer. 1960: 1937: 1933: 1908: 1903: 1894: 1858: 1822: 1813: 1804: 1787:, by Gauss' 1490:and for any 1391: 1387: 1383: 1379: 1375: 1369: 1217: 1212: 1180:-close to a 1147: 1136: 1005: 994: 984: 898: 879: 875: 867: 862: 820: 798: 793: 784: 782: 778: 773: 769: 768:is called a 767: 636: 533: 306: 302: 268: 103: 99: 95: 93: 83: 65: 48: 44: 38: 1994:: 347–375. 1826:John Nash, 871:convex sets 802:Lagrangians 49:h-principle 41:mathematics 18:H-principle 2023:Categories 1957:Gromov, M. 1938:-principle 1796:References 1421:such that 1182:Legendrian 90:Rough idea 2001:1111.2700 1521:⁡ 1475:− 1243:∞ 1150:homotopic 1143:holonomic 1119:α 1116:⁡ 1107:˙ 1095:α 1092:⁡ 1083:˙ 1054:α 980:Gauss map 947:↦ 924:θ 918:↦ 915:θ 846:≠ 731:… 686:… 649:Ψ 599:∂ 596:… 576:∂ 562:∂ 497:… 452:… 415:Ψ 375:… 214:… 182:Ψ 143:… 1959:(1986). 1230:smooth ( 1139:robotics 863:ordinary 833:′ 789:deformed 76:homotopy 1967:  1945:  783:A PDE 303:ƒ 269:where 96:ƒ 43:, the 1996:arXiv 1980:"The 1228:short 1965:ISBN 1943:ISBN 1615:The 1518:grad 1026:and 887:The 47:(or 2006:doi 1378:on 1284:in 1113:cos 1089:sin 98:on 39:In 2025:: 2004:. 1992:49 1990:. 1986:. 1510:, 1454:, 1215:. 1145:. 995:k, 849:0. 808:. 776:. 70:, 2014:. 2008:: 1998:: 1982:h 1973:. 1951:. 1936:h 1875:1 1871:C 1839:1 1835:C 1791:. 1773:2 1769:S 1746:2 1742:C 1715:2 1711:C 1688:3 1683:R 1659:2 1655:S 1632:1 1628:C 1612:. 1598:2 1594:S 1571:1 1567:C 1537:) 1532:t 1528:f 1524:( 1498:t 1478:f 1472:= 1467:1 1463:f 1442:f 1439:= 1434:0 1430:f 1407:t 1403:f 1392:x 1388:x 1386:( 1384:f 1380:R 1376:f 1332:1 1328:C 1305:1 1302:+ 1299:m 1294:R 1270:m 1266:M 1239:C 1211:- 1197:0 1193:C 1166:0 1162:C 1122:. 1104:y 1098:= 1080:x 1034:y 1014:x 955:n 951:z 944:z 936:( 921:n 895:. 843:) 840:x 837:( 830:f 753:0 750:= 747:) 742:N 738:y 734:, 728:, 723:2 719:y 715:, 710:1 706:y 702:, 697:m 693:u 689:, 683:, 678:2 674:u 670:, 665:1 661:u 657:( 622:. 612:k 608:j 603:u 589:1 585:j 580:u 571:f 566:k 555:= 550:j 546:y 519:0 516:= 513:) 508:N 504:y 500:, 494:, 489:2 485:y 481:, 476:1 472:y 468:, 463:m 459:u 455:, 449:, 444:2 440:u 436:, 431:1 427:u 423:( 391:. 386:N 382:y 378:, 372:, 367:2 363:y 359:, 354:1 350:y 327:k 322:f 318:J 307:k 287:k 282:f 278:J 254:0 251:= 248:) 243:k 238:f 234:J 230:, 225:m 221:u 217:, 211:, 206:2 202:u 198:, 193:1 189:u 185:( 159:) 154:m 150:u 146:, 140:, 135:2 131:u 127:, 122:1 118:u 114:( 104:k 100:R 84:C 35:. 20:)

Index

H-principle

sphere eversion
mathematics
partial differential equations
partial differential relations
underdetermined
Yakov Eliashberg
Mikhail Gromov
homotopy
Whitney–Graustein theorem
deformed
Lagrangians
pseudo-holomorphic curves
convex sets

Whitney–Graustein theorem
turning number
winding number
universal covering space
Whitney–Graustein theorem
turning number
Gauss map
Stiefel manifolds
frame bundles
robotics
holonomic
homotopic
Legendrian
Nash embedding theorem

Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.

↑