Knowledge (XXG)

Bridge (graph theory)

Source 📝

31: 221:, vertices that belong to every path between some pair of other vertices. The two endpoints of a bridge are articulation vertices unless they have a degree of 1, although it may also be possible for a non-bridge edge to have two articulation vertices as endpoints. Analogously to bridgeless graphs being 2-edge-connected, graphs without articulation vertices are 39: 200:
on the vertices according to which two vertices are related to each other whenever there are two edge-disjoint paths connecting them. (Every vertex is related to itself via two length-zero paths, which are identical but nevertheless edge-disjoint.) The equivalence classes of this relation are called
97:
This type of bridge should be distinguished from an unrelated meaning of "bridge" in graph theory, a subgraph separated from the rest of the graph by a specified subset of vertices; see
904: 1012:, stopping at the first vertex that is marked as visited. During such a traversal, every traversed vertex is marked as visited. Thus, a traversal stops at the latest at 851: 431: 713: 644: 552: 463: 183: 157: 944: 924: 816: 796: 773: 753: 733: 684: 664: 612: 592: 572: 523: 503: 483: 396: 369: 346: 321: 131: 279:(1978 and 1979, independently), which states that every bridgeless graph admits a multi-set of simple cycles which contains each edge exactly twice. 981:), giving a general framework for testing 2-edge- and 2-vertex-connectivity (which extends to linear-time 3-edge- and 3-vertex-connectivity tests). 1380: 245: 75: 1318: 1244: 268: 272: 71: 1483: 646:, the highest preorder label reachable by a path for which all but the last edge stays within the subtree rooted at 222: 102: 98: 67: 253: 205:, and the bridges of the graph are exactly the edges whose endpoints belong to different components. The 1197: 974: 190: 1437: 856: 197: 79: 1045: 958: 326: 257: 218: 186: 1222: 1449: 1345: 1202: 997: 261: 83: 961:. Chain decompositions do not only allow to compute all bridges of a graph, they also allow to 1376: 1240: 1184: 1126: 291:
algorithm (linear in the number of edges) for finding the bridges in a graph was described by
249: 1459: 1408: 1368: 1335: 1327: 1284: 1232: 1226: 821: 1420: 1296: 1254: 404: 1416: 1313: 1292: 1250: 1016:
and forms either a directed path or cycle, beginning with v; we call this path or cycle a
992:
and can be computed very simply: Let every vertex be marked as unvisited. For each vertex
689: 620: 528: 439: 300: 276: 375:
and number the nodes. Parent nodes in the forest now have lower numbers than child nodes.
162: 136: 1268: 929: 909: 801: 781: 758: 738: 718: 669: 649: 597: 577: 557: 508: 488: 468: 381: 372: 354: 331: 306: 209:
of the graph has a vertex for every nontrivial component and an edge for every bridge.
116: 1372: 1231:, Graduate Texts in Mathematics, vol. 184, New York: Springer-Verlag, p. 6, 1477: 1412: 1396: 1272: 292: 1316:(1939), "A theorem on graphs, with an application to a problem of traffic control", 1004:, traverse every backedge (i.e. every edge not in the DFS tree) that is incident to 159:
bridges, since adding additional edges must create a cycle. The graphs with exactly
47: 288: 229: 17: 244:
is a graph that does not have any bridges. Equivalent conditions are that each
1463: 1340: 1236: 966: 78:. Equivalently, an edge is a bridge if and only if it is not contained in any 30: 485:
by a path for which all but the last edge stays within the subtree rooted at
984:
Chain decompositions are special ear decompositions depending on a DFS-tree
1275:(1992), "Maintaining bridge-connected and biconnected components on-line", 1349: 1288: 38: 433:
for this node, by adding one to the sum of its children's descendants.
666:. This is the maximum of the set consisting of the preorder label of 505:. This is the minimum of the set consisting of the preorder label of 1363:
Jaeger, F. (1985), "A survey of the cycle double cover conjecture",
1331: 1454: 1367:, North-Holland Mathematics Studies, vol. 27, pp. 1–12, 37: 29: 189:, and the graphs in which every edge is a bridge are exactly the 398:
in preorder (denoting each node using its preorder number), do:
27:
Edge in node-link graph whose removal would disconnect the graph
1440:(2013), "A Simple Test on 2-Vertex- and 2-Edge-Connectivity", 34:
A graph with 16 vertices and six bridges (highlighted in red)
82:. For a connected graph, a bridge can uniquely determine a 232:, every cut vertex is an endpoint of at least one bridge. 1008:
and follow the path of tree-edges back to the root of
1076:
be a chain decomposition of a simple connected graph
932: 912: 859: 824: 804: 784: 761: 741: 721: 692: 672: 652: 623: 600: 580: 560: 531: 511: 491: 471: 442: 407: 384: 357: 334: 309: 165: 139: 119: 1399:(1974), "A note on finding the bridges of a graph", 1365:
Annals of Discrete Mathematics 27 – Cycles in Graphs
1024:th chain found by this procedure is referred to as 735:and of the preorder labels of nodes reachable from 574:and of the preorder labels of nodes reachable from 267:An important open problem involving bridges is the 938: 918: 898: 845: 810: 790: 767: 747: 727: 707: 678: 658: 638: 606: 586: 566: 546: 517: 497: 477: 457: 425: 390: 363: 340: 315: 177: 151: 125: 42:An undirected connected graph with no bridge edges 1087:is 2-edge-connected if and only if the chains in 74:whose deletion increases the graph's number of 1056:The following characterizations then allow to 217:Bridges are closely related to the concept of 8: 957:A very simple bridge-finding algorithm uses 1308: 1306: 465:, the lowest preorder label reachable from 295:in 1974. It performs the following steps: 1453: 1432: 1430: 1339: 931: 911: 858: 823: 803: 783: 760: 740: 720: 691: 671: 651: 622: 599: 579: 559: 530: 510: 490: 470: 441: 406: 401:Compute the number of forest descendants 383: 356: 333: 308: 164: 138: 118: 953:Bridge-finding with chain decompositions 282: 1214: 260:) that every connected component has a 196:In every undirected graph, there is an 1068:efficiently, including all bridges of 1135:is 2-vertex-connected if and only if 7: 252:, that each connected component is 1165:is the first vertex of a cycle in 25: 1319:The American Mathematical Monthly 1110:is not contained in any chain in 283:Tarjan's bridge-finding algorithm 1161:is a cut vertex if and only if 899:{\displaystyle H(w)<w+ND(w)} 755:by edges that do not belong to 594:by edges that do not belong to 213:Relation to vertex connectivity 1442:Information Processing Letters 1401:Information Processing Letters 893: 887: 869: 863: 834: 828: 702: 696: 633: 627: 541: 535: 452: 446: 420: 414: 1: 1373:10.1016/S0304-0208(08)72993-1 269:cycle double cover conjecture 1413:10.1016/0020-0190(74)90003-9 1157:in a 2-edge-connected graph 1106:is a bridge if and only if 203:2-edge-connected components 94:if it contains no bridges. 1500: 133:nodes can contain at most 1464:10.1016/j.ipl.2013.01.016 1237:10.1007/978-1-4612-0619-4 1139:has minimum degree 2 and 348:from the spanning forest 185:bridges are exactly the 103:Glossary of graph theory 86:. A graph is said to be 1179:is 2-vertex-connected, 1185:open ear decomposition 1060:several properties of 940: 920: 900: 847: 846:{\displaystyle L(w)=w} 812: 792: 769: 749: 729: 709: 680: 660: 640: 608: 588: 568: 548: 519: 499: 479: 459: 427: 392: 365: 342: 317: 250:open ear decomposition 179: 153: 127: 43: 35: 1198:Biconnected component 1146:is the only cycle in 1121:is 2-edge-connected, 941: 921: 901: 848: 813: 793: 770: 750: 730: 710: 681: 661: 641: 609: 589: 569: 549: 520: 500: 480: 460: 428: 426:{\displaystyle ND(v)} 393: 366: 343: 318: 219:articulation vertices 180: 154: 128: 41: 33: 959:chain decompositions 930: 910: 857: 822: 802: 782: 759: 739: 719: 708:{\displaystyle H(w)} 690: 670: 650: 639:{\displaystyle H(v)} 621: 598: 578: 558: 547:{\displaystyle L(w)} 529: 509: 489: 469: 458:{\displaystyle L(v)} 440: 405: 382: 355: 351:Traverse the forest 332: 307: 248:of the graph has an 198:equivalence relation 163: 137: 117: 76:connected components 1228:Modern Graph Theory 1046:chain decomposition 906:then the edge from 686:, of the values of 617:Similarly, compute 525:, of the values of 246:connected component 178:{\displaystyle n-1} 152:{\displaystyle n-1} 1484:Graph connectivity 1341:10338.dmlcz/101517 1289:10.1007/BF01758773 1269:Westbrook, Jeffery 1203:Cut (graph theory) 936: 916: 896: 843: 808: 788: 765: 745: 725: 715:at child nodes of 705: 676: 656: 636: 604: 584: 564: 554:at child nodes of 544: 515: 495: 475: 455: 423: 388: 361: 338: 313: 262:strong orientation 223:2-vertex-connected 175: 149: 123: 44: 36: 1382:978-0-444-87803-8 1273:Tarjan, Robert E. 1127:ear decomposition 939:{\displaystyle w} 919:{\displaystyle v} 811:{\displaystyle v} 798:with parent node 791:{\displaystyle w} 768:{\displaystyle F} 748:{\displaystyle v} 728:{\displaystyle v} 679:{\displaystyle v} 659:{\displaystyle v} 607:{\displaystyle F} 587:{\displaystyle v} 567:{\displaystyle v} 518:{\displaystyle v} 498:{\displaystyle v} 478:{\displaystyle v} 391:{\displaystyle v} 364:{\displaystyle F} 341:{\displaystyle F} 316:{\displaystyle G} 236:Bridgeless graphs 207:bridge-block tree 126:{\displaystyle n} 109:Trees and forests 16:(Redirected from 1491: 1468: 1466: 1457: 1438:Schmidt, Jens M. 1434: 1425: 1423: 1397:Tarjan, R. Endre 1393: 1387: 1385: 1360: 1354: 1352: 1343: 1310: 1301: 1299: 1283:(5–6): 433–464, 1265: 1259: 1257: 1219: 945: 943: 942: 937: 925: 923: 922: 917: 905: 903: 902: 897: 852: 850: 849: 844: 817: 815: 814: 809: 797: 795: 794: 789: 774: 772: 771: 766: 754: 752: 751: 746: 734: 732: 731: 726: 714: 712: 711: 706: 685: 683: 682: 677: 665: 663: 662: 657: 645: 643: 642: 637: 613: 611: 610: 605: 593: 591: 590: 585: 573: 571: 570: 565: 553: 551: 550: 545: 524: 522: 521: 516: 504: 502: 501: 496: 484: 482: 481: 476: 464: 462: 461: 456: 432: 430: 429: 424: 397: 395: 394: 389: 370: 368: 367: 362: 347: 345: 344: 339: 322: 320: 319: 314: 258:Robbins' theorem 254:2-edge-connected 242:bridgeless graph 184: 182: 181: 176: 158: 156: 155: 150: 132: 130: 129: 124: 21: 18:Bridgeless graph 1499: 1498: 1494: 1493: 1492: 1490: 1489: 1488: 1474: 1473: 1472: 1471: 1436: 1435: 1428: 1395: 1394: 1390: 1383: 1362: 1361: 1357: 1332:10.2307/2303897 1312: 1311: 1304: 1267: 1266: 1262: 1247: 1221: 1220: 1216: 1211: 1194: 1170: 1144: 1040: 1036: 1029: 955: 928: 927: 908: 907: 855: 854: 820: 819: 800: 799: 780: 779: 757: 756: 737: 736: 717: 716: 688: 687: 668: 667: 648: 647: 619: 618: 596: 595: 576: 575: 556: 555: 527: 526: 507: 506: 487: 486: 467: 466: 438: 437: 403: 402: 380: 379: 353: 352: 330: 329: 305: 304: 301:spanning forest 285: 238: 215: 161: 160: 135: 134: 115: 114: 111: 28: 23: 22: 15: 12: 11: 5: 1497: 1495: 1487: 1486: 1476: 1475: 1470: 1469: 1448:(7): 241–244, 1426: 1407:(6): 160–161, 1388: 1381: 1355: 1326:(5): 281–283, 1314:Robbins, H. E. 1302: 1260: 1245: 1223:Bollobás, Béla 1213: 1212: 1210: 1207: 1206: 1205: 1200: 1193: 1190: 1189: 1188: 1173: 1168: 1151: 1142: 1130: 1115: 1096: 1038: 1034: 1027: 975:block-cut tree 954: 951: 950: 949: 948: 947: 935: 915: 895: 892: 889: 886: 883: 880: 877: 874: 871: 868: 865: 862: 842: 839: 836: 833: 830: 827: 807: 787: 778:For each node 776: 764: 744: 724: 704: 701: 698: 695: 675: 655: 635: 632: 629: 626: 615: 603: 583: 563: 543: 540: 537: 534: 514: 494: 474: 454: 451: 448: 445: 434: 422: 419: 416: 413: 410: 387: 378:For each node 376: 360: 349: 337: 323: 312: 284: 281: 237: 234: 214: 211: 174: 171: 168: 148: 145: 142: 122: 110: 107: 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 1496: 1485: 1482: 1481: 1479: 1465: 1461: 1456: 1451: 1447: 1443: 1439: 1433: 1431: 1427: 1422: 1418: 1414: 1410: 1406: 1402: 1398: 1392: 1389: 1384: 1378: 1374: 1370: 1366: 1359: 1356: 1351: 1347: 1342: 1337: 1333: 1329: 1325: 1321: 1320: 1315: 1309: 1307: 1303: 1298: 1294: 1290: 1286: 1282: 1278: 1274: 1270: 1264: 1261: 1256: 1252: 1248: 1246:0-387-98488-7 1242: 1238: 1234: 1230: 1229: 1224: 1218: 1215: 1208: 1204: 1201: 1199: 1196: 1195: 1191: 1186: 1182: 1178: 1174: 1171: 1164: 1160: 1156: 1152: 1149: 1145: 1138: 1134: 1131: 1128: 1124: 1120: 1116: 1113: 1109: 1105: 1101: 1097: 1094: 1090: 1086: 1083: 1082: 1081: 1079: 1075: 1071: 1067: 1063: 1059: 1054: 1052: 1048: 1047: 1042: 1030: 1023: 1019: 1015: 1011: 1007: 1003: 1000:-numbers 1... 999: 996:in ascending 995: 991: 987: 982: 980: 976: 972: 968: 964: 960: 952: 933: 913: 890: 884: 881: 878: 875: 872: 866: 860: 840: 837: 831: 825: 805: 785: 777: 762: 742: 722: 699: 693: 673: 653: 630: 624: 616: 601: 581: 561: 538: 532: 512: 492: 472: 449: 443: 435: 417: 411: 408: 400: 399: 385: 377: 374: 358: 350: 335: 328: 327:Rooted forest 324: 310: 302: 298: 297: 296: 294: 293:Robert Tarjan 290: 280: 278: 274: 270: 265: 263: 259: 255: 251: 247: 243: 235: 233: 231: 226: 224: 220: 212: 210: 208: 204: 199: 194: 192: 188: 172: 169: 166: 146: 143: 140: 120: 113:A graph with 108: 106: 104: 100: 95: 93: 89: 85: 81: 77: 73: 69: 65: 61: 57: 53: 49: 40: 32: 19: 1445: 1441: 1404: 1400: 1391: 1364: 1358: 1323: 1317: 1280: 1277:Algorithmica 1276: 1263: 1227: 1217: 1180: 1176: 1166: 1162: 1158: 1154: 1147: 1140: 1136: 1132: 1122: 1118: 1111: 1107: 1103: 1099: 1092: 1088: 1084: 1077: 1073: 1069: 1065: 1061: 1057: 1055: 1050: 1044: 1032: 1025: 1021: 1017: 1013: 1009: 1005: 1001: 993: 989: 985: 983: 978: 970: 962: 956: 946:is a bridge. 286: 266: 241: 239: 227: 216: 206: 202: 195: 112: 96: 92:isthmus-free 91: 87: 63: 59: 55: 51: 48:graph theory 45: 289:linear time 230:cubic graph 1091:partition 1043:is then a 967:cut vertex 287:The first 88:bridgeless 1455:1209.0700 1153:A vertex 973:(and the 325:Create a 271:, due to 256:, or (by 170:− 144:− 1478:Category 1225:(1998), 1192:See also 1098:An edge 1058:read off 963:read off 436:Compute 373:preorder 277:Szekeres 60:cut-edge 1421:0349483 1350:2303897 1297:1154584 1255:1633290 1078:G=(V,E) 299:Find a 273:Seymour 191:forests 101:in the 64:cut arc 56:isthmus 1419:  1379:  1348:  1295:  1253:  1243:  1183:is an 1125:is an 1072:. Let 1020:. The 965:every 99:bridge 66:is an 52:bridge 1450:arXiv 1346:JSTOR 1209:Notes 1167:C - C 1064:from 1018:chain 818:, if 228:In a 187:trees 80:cycle 72:graph 70:of a 62:, or 1377:ISBN 1241:ISBN 1041:,... 873:< 853:and 275:and 68:edge 50:, a 1460:doi 1446:113 1409:doi 1369:doi 1336:hdl 1328:doi 1285:doi 1233:doi 1175:If 1117:If 1102:in 1049:of 1033:C=C 998:DFS 988:of 977:of 969:of 926:to 371:in 303:of 90:or 84:cut 46:In 1480:: 1458:, 1444:, 1429:^ 1417:MR 1415:, 1403:, 1375:, 1344:, 1334:, 1324:46 1322:, 1305:^ 1293:MR 1291:, 1279:, 1271:; 1251:MR 1249:, 1239:, 1080:. 1053:. 1037:,C 1031:. 264:. 240:A 225:. 193:. 105:. 58:, 54:, 1467:. 1462:: 1452:: 1424:. 1411:: 1405:2 1386:. 1371:: 1353:. 1338:: 1330:: 1300:. 1287:: 1281:7 1258:. 1235:: 1187:. 1181:C 1177:G 1172:. 1169:1 1163:v 1159:G 1155:v 1150:. 1148:C 1143:1 1141:C 1137:G 1133:G 1129:. 1123:C 1119:G 1114:. 1112:C 1108:e 1104:G 1100:e 1095:. 1093:E 1089:C 1085:G 1074:C 1070:G 1066:C 1062:G 1051:G 1039:2 1035:1 1028:i 1026:C 1022:i 1014:v 1010:T 1006:v 1002:n 994:v 990:G 986:T 979:G 971:G 934:w 914:v 894:) 891:w 888:( 885:D 882:N 879:+ 876:w 870:) 867:w 864:( 861:H 841:w 838:= 835:) 832:w 829:( 826:L 806:v 786:w 775:. 763:F 743:v 723:v 703:) 700:w 697:( 694:H 674:v 654:v 634:) 631:v 628:( 625:H 614:. 602:F 582:v 562:v 542:) 539:w 536:( 533:L 513:v 493:v 473:v 453:) 450:v 447:( 444:L 421:) 418:v 415:( 412:D 409:N 386:v 359:F 336:F 311:G 173:1 167:n 147:1 141:n 121:n 20:)

Index

Bridgeless graph


graph theory
edge
graph
connected components
cycle
cut
bridge
Glossary of graph theory
trees
forests
equivalence relation
articulation vertices
2-vertex-connected
cubic graph
connected component
open ear decomposition
2-edge-connected
Robbins' theorem
strong orientation
cycle double cover conjecture
Seymour
Szekeres
linear time
Robert Tarjan
spanning forest
Rooted forest
preorder

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