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Conformally flat manifold

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provides a coordinate system for the sphere in which conformal flatness is explicit, as the metric is proportional to the flat one.
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the angles by moving from one to the other, as well as keeping the null geodesics unchanged, that means there exists a function
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Garat, Alcides; Price, Richard H. (2000-05-18). "Nonexistence of conformally flat slices of the Kerr spacetime".
177: 1831: 1129:{\displaystyle ds^{2}=d\theta ^{2}+\sin ^{2}\theta \,d\phi ^{2}\,={\frac {4}{(1+r^{2})^{2}}}(dx^{2}+dy^{2})} 2063: 736: 259: 2058: 1725: 1712:{\displaystyle g_{ik}={\begin{bmatrix}1-{\frac {2GM}{r}}&0\\0&-1+{\frac {2GM}{r}}\end{bmatrix}}} 1400:{\displaystyle g_{ik}={\begin{bmatrix}0&1-{\frac {2GM}{r}}\\1-{\frac {2GM}{r}}&0\end{bmatrix}}} 915: 36: 1773: 2013: 1183: 909: 522: 52: 475: 232: 148: 1879:
Garecki, Janusz (2008). "On Energy of the Friedman Universes in Conformally Flat Coordinates".
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Spherical coordinate system - Integration and differentiation in spherical coordinates
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The upper manifold is flat. The lower one is not, but it is conformal to the first one
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A 3-dimensional pseudo-Riemannian manifold is conformally flat if and only if the
901:{\displaystyle g_{ik}={\begin{bmatrix}1&0\\0&sin^{2}\theta \end{bmatrix}}} 430: 2009: 1947: 1783: 1202: 2052: 1955: 1201:. However it was also shown that there are no conformally flat slices of the 1171:, conformally Euclidean Riemannian manifold is conformally equivalent to the 1164: 1142: 518: 59: 48: 1997: 732: 1157: 1865: 735:
of the two dimensional spherical coordinates, like the one used in the
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conformally flat manifolds can often be used, for example to describe
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Every 2-dimensional pseudo-Riemannian manifold is conformally flat.
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Kuiper, N. H. (1949). "On conformally flat spaces in the large".
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is the distance from the origin of the flat space, obtaining
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can be mapped to a flat space using the conformal factor
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if each point has a neighborhood that can be mapped to
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which is the flat metric times the conformal factor
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for the case in which the relation is valid for all
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Then 1832:Stereographic projection - Properties 1992: 1801: 1799: 908: and is not flat but with the 621:Some authors use the definition of 24: 1756:{\displaystyle 1-{\frac {2GM}{r}}} 25: 2085: 1979:Introducing Einstein's Relativity 1808:Introducing Einstein's Relativity 1796: 951:{\displaystyle 2 \over (1+r^{2})} 625:when referred to just some point 1996: 1970: 1909: 1872: 1837: 1825: 1814: 1592: 1560: 1478: 1466: 1432: 1420: 1123: 1091: 1079: 1059: 944: 925: 665:and reserve the definition of 598:need not be defined on all of 504: 479: 389:, there exists a neighborhood 336: 324: 304: 292: 245: 239: 212: 206: 190: 184: 161: 155: 13: 1: 1789: 2012:. You can help Knowledge by 1212:Kruskal-Szekeres coordinates 737:geographic coordinate system 282:is a point on the manifold. 7: 1843: 1767: 712: 510:{\displaystyle (U,e^{2f}g)} 251:{\displaystyle \lambda (x)} 167:{\displaystyle \lambda (x)} 10: 2090: 1991: 1948:10.1103/PhysRevD.61.124011 125:maintain in all points of 2074:Riemannian geometry stubs 1492:{\displaystyle x=(v-u)/2} 1446:{\displaystyle t=(v+u)/2} 1184:stereographic projection 910:stereographic projection 623:locally conformally flat 53:conformal transformation 18:Locally conformally flat 1881:Acta Physica Polonica B 1834:. The Riemann's formula 551:{\displaystyle e^{2f}g} 2008:-related article is a 1757: 1713: 1599: 1493: 1447: 1401: 1290: 1130: 972: 952: 902: 817: 703: 683: 659: 639: 612: 592: 572: 552: 511: 466: 446: 423: 403: 383: 363: 343: 311: 276: 252: 223: 168: 139: 115: 95: 75: 32: 1846:Annals of Mathematics 1774:Weyl–Schouten theorem 1758: 1714: 1600: 1494: 1448: 1402: 1291: 1131: 973: 953: 903: 818: 704: 684: 660: 640: 613: 593: 573: 553: 512: 467: 447: 424: 404: 384: 364: 344: 342:{\displaystyle (M,g)} 312: 310:{\displaystyle (M,g)} 277: 253: 224: 169: 140: 116: 114:{\displaystyle \eta } 96: 76: 30: 1726: 1609: 1507: 1457: 1411: 1300: 1220: 984: 962: 916: 827: 823:, has metric tensor 747: 725:is conformally flat. 718:Every manifold with 693: 673: 649: 629: 602: 582: 562: 529: 476: 456: 436: 413: 393: 373: 353: 321: 289: 266: 233: 178: 149: 129: 105: 85: 65: 2064:Riemannian geometry 2006:Riemannian geometry 1981:. pp. 230–231. 1940:2000PhRvD..61l4011G 1903:2008AcPPB..39..781G 1605:with metric tensor 1296:with metric tensor 723:sectional curvature 285:More formally, let 41:Riemannian manifold 2059:Conformal geometry 1779:conformal geometry 1753: 1709: 1703: 1595: 1489: 1443: 1397: 1391: 1286: 1195:general relativity 1126: 968: 923: 898: 892: 813: 699: 679: 655: 635: 608: 588: 568: 548: 507: 462: 442: 419: 399: 379: 359: 339: 307: 272: 248: 219: 164: 135: 111: 91: 71: 33: 2021: 2020: 1918:Physical Review D 1810:. pp. 88–89. 1751: 1699: 1658: 1553: 1382: 1354: 1266: 1214:have line element 1210:For example, the 1089: 971:{\displaystyle r} 948: 702:{\displaystyle M} 682:{\displaystyle x} 658:{\displaystyle M} 638:{\displaystyle x} 611:{\displaystyle M} 591:{\displaystyle f} 571:{\displaystyle U} 465:{\displaystyle U} 445:{\displaystyle f} 422:{\displaystyle x} 402:{\displaystyle U} 382:{\displaystyle M} 362:{\displaystyle x} 275:{\displaystyle x} 138:{\displaystyle M} 94:{\displaystyle M} 74:{\displaystyle g} 58:In practice, the 16:(Redirected from 2081: 2042: 2035: 2028: 2000: 1993: 1983: 1982: 1974: 1968: 1967: 1933: 1913: 1907: 1906: 1896: 1876: 1870: 1869: 1841: 1835: 1829: 1823: 1818: 1812: 1811: 1803: 1762: 1760: 1759: 1754: 1752: 1747: 1736: 1718: 1716: 1715: 1710: 1708: 1707: 1700: 1695: 1684: 1659: 1654: 1643: 1624: 1623: 1604: 1602: 1601: 1596: 1591: 1590: 1575: 1574: 1559: 1555: 1554: 1549: 1538: 1522: 1521: 1498: 1496: 1495: 1490: 1485: 1452: 1450: 1449: 1444: 1439: 1406: 1404: 1403: 1398: 1396: 1395: 1383: 1378: 1367: 1355: 1350: 1339: 1315: 1314: 1295: 1293: 1292: 1287: 1272: 1268: 1267: 1262: 1251: 1235: 1234: 1169:simply connected 1135: 1133: 1132: 1127: 1122: 1121: 1106: 1105: 1090: 1088: 1087: 1086: 1077: 1076: 1054: 1048: 1047: 1028: 1027: 1015: 1014: 999: 998: 977: 975: 974: 969: 957: 955: 954: 949: 947: 943: 942: 918: 907: 905: 904: 899: 897: 896: 886: 885: 842: 841: 822: 820: 819: 814: 811: 810: 791: 790: 778: 777: 762: 761: 708: 706: 705: 700: 688: 686: 685: 680: 667:conformally flat 664: 662: 661: 656: 644: 642: 641: 636: 617: 615: 614: 609: 597: 595: 594: 589: 578:). The function 577: 575: 574: 569: 557: 555: 554: 549: 544: 543: 516: 514: 513: 508: 500: 499: 471: 469: 468: 463: 451: 449: 448: 443: 428: 426: 425: 420: 408: 406: 405: 400: 388: 386: 385: 380: 368: 366: 365: 360: 348: 346: 345: 340: 316: 314: 313: 308: 281: 279: 278: 273: 260:conformal factor 258:is known as the 257: 255: 254: 249: 228: 226: 225: 220: 205: 204: 173: 171: 170: 165: 144: 142: 141: 136: 120: 118: 117: 112: 100: 98: 97: 92: 81:of the manifold 80: 78: 77: 72: 45:conformally flat 21: 2089: 2088: 2084: 2083: 2082: 2080: 2079: 2078: 2049: 2048: 2047: 2046: 1989: 1987: 1986: 1975: 1971: 1914: 1910: 1877: 1873: 1858:10.2307/1969587 1842: 1838: 1830: 1826: 1819: 1815: 1804: 1797: 1792: 1770: 1737: 1735: 1727: 1724: 1723: 1702: 1701: 1685: 1683: 1672: 1666: 1665: 1660: 1644: 1642: 1629: 1628: 1616: 1612: 1610: 1607: 1606: 1586: 1582: 1570: 1566: 1539: 1537: 1530: 1526: 1517: 1513: 1508: 1505: 1504: 1481: 1458: 1455: 1454: 1435: 1412: 1409: 1408: 1390: 1389: 1384: 1368: 1366: 1357: 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781–797. 1871: 1852:(4): 916–924. 1836: 1824: 1813: 1794: 1793: 1791: 1788: 1787: 1786: 1784:Yamabe problem 1781: 1776: 1769: 1766: 1765: 1764: 1750: 1746: 1743: 1740: 1734: 1731: 1720: 1706: 1698: 1694: 1691: 1688: 1682: 1679: 1676: 1673: 1671: 1668: 1667: 1664: 1661: 1657: 1653: 1650: 1647: 1641: 1638: 1635: 1634: 1632: 1627: 1622: 1619: 1615: 1594: 1589: 1585: 1581: 1578: 1573: 1569: 1565: 1562: 1558: 1552: 1548: 1545: 1542: 1536: 1533: 1529: 1525: 1520: 1516: 1512: 1502: 1499: 1488: 1484: 1480: 1477: 1474: 1471: 1468: 1465: 1462: 1442: 1438: 1434: 1431: 1428: 1425: 1422: 1419: 1416: 1394: 1388: 1385: 1381: 1377: 1374: 1371: 1365: 1362: 1359: 1358: 1353: 1349: 1346: 1343: 1337: 1334: 1331: 1329: 1326: 1325: 1323: 1318: 1313: 1310: 1306: 1285: 1282: 1278: 1275: 1271: 1265: 1261: 1258: 1255: 1249: 1246: 1242: 1238: 1233: 1229: 1225: 1215: 1207: 1206: 1203:Kerr spacetime 1190: 1189: 1188: 1187: 1177: 1176: 1161: 1146: 1139: 1138: 1137: 1125: 1120: 1116: 1112: 1109: 1104: 1100: 1096: 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1036: 1032: 1029: 1024: 1020: 1016: 1011: 1007: 1003: 1000: 995: 991: 987: 980: 965: 939: 935: 931: 928: 920: 911: 893: 887: 882: 878: 874: 871: 866: 859: 854: 848: 843: 838: 835: 831: 807: 803: 799: 795: 792: 787: 783: 779: 774: 770: 766: 763: 758: 754: 750: 743: 742: 738: 734: 730: 729: 727: 724: 721: 717: 716: 710: 696: 676: 668: 652: 632: 624: 619: 605: 585: 565: 545: 540: 537: 533: 524: 520: 501: 496: 493: 489: 485: 482: 459: 439: 432: 416: 396: 376: 356: 333: 330: 327: 301: 298: 295: 283: 269: 261: 242: 236: 216: 209: 201: 197: 193: 187: 181: 158: 152: 132: 124: 108: 88: 68: 61: 56: 54: 50: 46: 42: 38: 29: 19: 2014:expanding it 2003: 1988: 1978: 1972: 1921: 1917: 1911: 1884: 1880: 1874: 1849: 1845: 1839: 1827: 1816: 1807: 1173:round sphere 1153: 1149: 733:line element 666: 622: 620: 558:vanishes on 284: 121:, i.e., the 57: 44: 34: 1158:Weyl tensor 452:defined on 2053:Categories 1790:References 521:(i.e. the 472:such that 174:such that 49:flat space 2069:Manifolds 1964:119452751 1956:0556-2821 1894:0708.2783 1733:− 1675:− 1640:− 1577:− 1535:− 1473:− 1364:− 1336:− 1248:− 1160:vanishes. 1145:vanishes. 1041:ϕ 1033:θ 1030:⁡ 1008:θ 888:θ 804:ϕ 796:θ 793:⁡ 771:θ 523:curvature 237:λ 217:η 198:λ 153:λ 123:geodesics 109:η 1768:See also 958:, where 720:constant 713:Examples 229:, where 1936:Bibcode 1899:Bibcode 1866:1969587 1501:becomes 1165:compact 1962:  1954:  1864:  1163:Every 429:and a 60:metric 37:pseudo 2004:This 1960:S2CID 1926:arXiv 1889:arXiv 1862:JSTOR 51:by a 2010:stub 1952:ISSN 1453:and 1182:The 731:The 519:flat 262:and 1944:doi 1854:doi 1193:In 1148:An 1021:sin 784:sin 689:on 645:on 525:of 517:is 409:of 369:in 43:is 35:A ( 2055:: 1958:. 1950:. 1942:. 1934:. 1922:61 1920:. 1897:. 1885:39 1883:. 1860:. 1850:50 1848:. 1798:^ 1167:, 709:. 618:. 55:. 39:-) 2041:e 2034:t 2027:v 2016:. 1966:. 1946:: 1938:: 1928:: 1905:. 1901:: 1891:: 1868:. 1856:: 1763:. 1749:r 1745:M 1742:G 1739:2 1730:1 1719:, 1705:] 1697:r 1693:M 1690:G 1687:2 1681:+ 1678:1 1670:0 1663:0 1656:r 1652:M 1649:G 1646:2 1637:1 1631:[ 1626:= 1621:k 1618:i 1614:g 1593:) 1588:2 1584:x 1580:d 1572:2 1568:t 1564:d 1561:( 1557:) 1551:r 1547:M 1544:G 1541:2 1532:1 1528:( 1524:= 1519:2 1515:s 1511:d 1487:2 1483:/ 1479:) 1476:u 1470:v 1467:( 1464:= 1461:x 1441:2 1437:/ 1433:) 1430:u 1427:+ 1424:v 1421:( 1418:= 1415:t 1393:] 1387:0 1380:r 1376:M 1373:G 1370:2 1361:1 1352:r 1348:M 1345:G 1342:2 1333:1 1328:0 1322:[ 1317:= 1312:k 1309:i 1305:g 1284:u 1281:d 1277:v 1274:d 1270:) 1264:r 1260:M 1257:G 1254:2 1245:1 1241:( 1237:= 1232:2 1228:s 1224:d 1205:. 1175:. 1154:n 1150:n 1136:. 1124:) 1119:2 1115:y 1111:d 1108:+ 1103:2 1099:x 1095:d 1092:( 1084:2 1080:) 1074:2 1070:r 1066:+ 1063:1 1060:( 1056:4 1051:= 1045:2 1037:d 1025:2 1017:+ 1012:2 1004:d 1001:= 996:2 992:s 988:d 966:r 945:) 940:2 936:r 932:+ 929:1 926:( 921:2 894:] 883:2 879:n 875:i 872:s 867:0 860:0 855:1 849:[ 844:= 839:k 836:i 832:g 808:2 800:d 788:2 780:+ 775:2 767:d 764:= 759:2 755:s 751:d 739:, 697:M 677:x 653:M 633:x 606:M 586:f 566:U 546:g 541:f 538:2 534:e 505:) 502:g 497:f 494:2 490:e 486:, 483:U 480:( 460:U 440:f 417:x 397:U 377:M 357:x 337:) 334:g 331:, 328:M 325:( 305:) 302:g 299:, 296:M 293:( 270:x 246:) 243:x 240:( 213:) 210:x 207:( 202:2 194:= 191:) 188:x 185:( 182:g 162:) 159:x 156:( 133:M 89:M 69:g 20:)

Index

Locally conformally flat

pseudo
Riemannian manifold
flat space
conformal transformation
metric
geodesics
conformal factor
smooth function
flat
curvature
constant
sectional curvature
line element
geographic coordinate system
stereographic projection
Cotton tensor
Weyl tensor
compact
simply connected
round sphere
stereographic projection
general relativity
Friedmann–Lemaître–Robertson–Walker metric
Kerr spacetime
Kruskal-Szekeres coordinates
Weyl–Schouten theorem
conformal geometry
Yamabe problem

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