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Approximate max-flow min-cut theorem

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It is helpful to find a layout of minimum size when designing a VLSI circuit. Such a problem can often be modeled as a graph embedding problem. The objective is to find an embedding for which the layout area is minimized. Finding the minimum layout area is also NP-hard. An approximation algorithm has
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The research on the relationship between the max-flow and min-cut of multicommodity flow problem has obtained great interest since Ford and Fulkerson's result for 1-commodity flow problems. Hu showed that the max-flow and min-cut are always equal for two commodities. Okamura and Seymour illustrated a
287:, such that the total amount of all commodities passing through any edge is no greater than its capacity. (In the case of undirected edges, the sum of the flows in both directions cannot exceed the capacity of the edge). Specially, a 1-commodity (or single commodity) flow problem is also known as a 769:
To prove Theorem 2, both the max-flow and the min-cut should be discussed. For the max-flow, the techniques from duality theory of linear programming have to be employed. According to the duality theory of linear programming, an optimal distance function results in a total weight that is equal to
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In a uniform multicommodity flow problem, there is a commodity for every pair of nodes and the demand for every commodity is the same. (Without loss of generality, the demand for every commodity is set to one.) The underlying network and capacities are arbitrary.
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also proved that the max-flow and min-cut are equal provided the dual of the flow problem satisfies a certain cut condition in a uniform multicommodity flow problem. Many other researchers also showed concrete research results in similar problems
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is a partition for which the ratio of the number of edges connecting the two partitioned components over the product of the numbers of nodes of both components is minimized. This is a NP-hard problem, and it can be approximated to within
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The major difference in the proof methodology compared to Theorem 2 is that, now the edge directions need to be considered when defining distance labels in stage 1 and for growing the regions in stage 2, more details can be found in.
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In a directed multicommodity flow problem, each edge has a direction, and the flow is restricted to move in the specified direction. In a directed uniform multicommodity flow problem, the demand is set to 1 for every directed edge.
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Leighton, Tom; Rao, Satish (1988). "An approximate max-flow min-cut theorem for uniform multicommodity flow problems with applications to approximation algorithms".
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There are two theorems first introduced by Tom Leighton and Satish Rao in 1988 and then extended in 1999. Theorem 2 gives a tighter bound compared to Theorem 1.
1005: 904: 798: 686: 1988: 474:. The uniform multicommodity flow problem is a special case of the product multicommodity flow problem for which the weight is set to 1 for all nodes 1105:
problem and its variations. Here below we briefly introduce a few examples, and the in-depth elaborations can be found in Leighton and Rao (1999).
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Stage 2: Starting from a source or a sink, grow a region in the graph until find a cut of small enough capacity separating the root from its mate.
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Stage 1: Consider the dual of uniform commodity flow problem and use the optimal solution to define a graph with distance labels on the edges.
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Leighton, Tom; Rao, Satish (November 1999). "Multicommodity Max-Flow Min-Cut Theorems and Their Use in Designing Approximation Algorithms".
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factor using Theorem 2. Also, a sparsest cut problem with weighted edges, weighted nodes or directed edges can be approximated within an
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of the capacity of the cut to the demand of the cut. Max-flow is always upper bounded by the min-cut for a multicommodity flow problem.
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Klein, P.; Plotkin, S.; Rao, S.; Tardos, E. (1997). "Bounds on the max-flow min-cut ratio for directed multicommodity flows".
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The proof methodology is similar to that for Theorem 2; the major difference is to take node weights into consideration.
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is the problem of apportioning a fixed amount of weight (where weights can be considered as distances) to the edges of
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Garg, N.; Vazarani, V.; Yannakakis, M. (1996). "Approximate max-flow min-(multi)cut theorems and their applications".
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Chung, F. K.; Coffman, E. G.; Reiman, M. I.; Simon, B. E. (1987). "The forwarding index of communication networks".
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the max-flow of the uniform multicommodity flow problem. For the min-cut, a 3-stage process has to be followed:
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of the capacity of each edge. This is not a good result especially in case of large numbers of commodities.
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Plitkin, S.; Tardos, E. (1993). "Improved bounds on the max-flow min-cut ratio for multicommodity flows".
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problem. An approximation algorithm has been designed for this problem, and the core idea is that
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VLSI partitioning approximation algorithms based on multicommodity flows and other techniques
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Similarly, for product multicommodity flow problem, we have the following extended theorem:
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Stage 3: Remove the region and repeat the process of stage 2 until all nodes get processed.
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4-commodity flow problem with max-flow equals to 3/4 and min-cut equals 1. Shahrokhi and
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In a product multicommodity flow problem, there is a nonnegative weight for each node
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Tragoudas uses the approximation algorithm for balanced separators to find a set of
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of the embedding to be the maximum number of paths (each corresponding to an edge of
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such that to maximize the cumulative distance between the source and sink pairs.
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that partitions the graph into nearly equal-size pieces. We usually call a cut
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Okamura, H.; Seymour, P. D. (1981). "Multicommodity flows in planar graphs".
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is the number of nodes with nonzero weight according to Theorem 3, 4 and 5.
2178:(Ph.D. dissertation). Department of Computer Sciences, University of Texas. 295:, the max-flow and min-cut are always equal in a 1-commodity flow problem. 1972: 1932: 2132:
Proceedings of the 29th IEEE Symposium on Foundations of Computer Science
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For a general network flow problem, the max-flow is within a factor of
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of the min-cut since each commodity can be optimized separately using
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deal with the relationship between maximum flow rate ("max-flow") and
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A "commodity" in a network flow problem is a pair of source and sink
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before it becomes planar. It remains an open question if there is a
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Proceedings of the 25th Annual ACM Symposium on Theory of Computing
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is the directed min-cut of the product multicommodity flow problem.
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is the common fraction of each commodity that is routed, such that
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In general, the dual of a multicommodity flow problem for a graph
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In some applications, we want to find a small cut in a graph
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is the minimum number of edges that need to be removed from
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For any directed product multicommodity flow problem with
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is the min-cut of the uniform multicommodity flow problem.
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For any directed uniform multicommodity flow problem with
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is the min-cut of the product multicommodity flow problem.
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is the min-cut of the uniform multicommodity flow problem.
599:-node uniform multicommodity flow problem with max-flow 39: 1761: 1714: 1683: 1648: 1590: 1568:{\displaystyle O\left({\frac {S\log n}{b-b'}}\right)} 1519: 1485:{\displaystyle O\left(S\log {\frac {n}{b}}-b'\right)} 1438: 1382: 1369:{\displaystyle b\pi (V)\leq \pi (U)\leq (1-b)\pi (V)} 1305: 1240: 1193: 1158: 1119: 1070: 1008: 969: 907: 863: 801: 751: 689: 629: 609: 549: 480: 426: 400: 363: 321: 262: 235: 204: 177: 150: 123: 34:
may be too technical for most readers to understand
1824: 1735: 1696: 1661: 1618: 1567: 1484: 1397: 1368: 1264: 1214: 1179: 1143: 1076: 1052: 975: 951: 869: 845: 783:Generalized to product multicommodity flow problem 757: 733: 667: 615: 563: 492: 450: 412: 369: 337: 275: 248: 217: 190: 163: 136: 791:For any product multicommodity flow problem with 1832:edges whose removal from a bounded-degree graph 885:Extended to directed multicommodity flow problem 580:Theorems of uniform multicommodity flow problems 16:Mathematical propositions in network flow theory 113:. In a multi-commodity flow problem, there are 93:. The theorems have enabled the development of 1902: 1900: 1898: 1896: 1894: 1892: 1890: 1888: 1093:The above theorems are very useful to design 683:For any uniform multicommodity flow problem, 458:. The demand for the commodity between nodes 8: 1886: 1884: 1882: 1880: 1878: 1876: 1874: 1872: 1870: 1868: 353:without violating any capacity constraints. 198:. The objective is to simultaneously route 1851:times optimal approximation algorithm for 2038: 1989:Journal of Combinatorial Theory, Series B 1922: 1807: 1788: 1760: 1713: 1688: 1682: 1653: 1647: 1601: 1589: 1527: 1518: 1456: 1437: 1381: 1304: 1239: 1192: 1157: 1118: 1069: 1016: 1007: 968: 915: 906: 862: 809: 800: 750: 697: 688: 643: 628: 608: 553: 548: 479: 425: 399: 362: 329: 320: 267: 261: 240: 234: 209: 203: 182: 176: 155: 149: 128: 122: 62:Learn how and when to remove this message 46:, without removing the technical details. 2081: 2079: 1957:(1963). "Multicommodity network flows". 1089:Applications to approximation algorithms 357:is the minimum of all cuts of the ratio 2148:IEEE Transactions on Information Theory 1864: 466:is the product of the weights of node 349:can be simultaneously routed for each 117:commodities, each with its own source 2021:"The maximum concurrent flow problem" 575:Approximate max-flow min-cut theorems 75:Approximate max-flow min-cut theorems 44:make it understandable to non-experts 7: 390:Product multicommodity flow problem 381:Uniform multicommodity flow problem 1584:been introduced and the result is 1405:is the sum of the node weights in 1009: 908: 802: 690: 303:In a multicommodity flow problem, 14: 1836:results in a planar graph, where 77:are mathematical propositions in 1704:) that pass through any node of 23: 1798: 1770: 1730: 1718: 1613: 1594: 1392: 1386: 1363: 1357: 1351: 1339: 1333: 1327: 1318: 1312: 1259: 1247: 1209: 1197: 1174: 1162: 1138: 1126: 445: 433: 1: 2002:10.1016/S0095-8956(81)80012-3 1619:{\displaystyle O(\log ^{6}n)} 504:Duality of linear programming 338:{\displaystyle fD_{\text{i}}} 1230:Balanced cuts and separators 218:{\displaystyle D_{\text{i}}} 91:multi-commodity flow problem 1673:, Chung et al. defined the 105:Multicommodity flow problem 2217: 1113:A sparsest cut of a graph 507: 2102:10.1137/s0097539793243016 2089:SIAM Journal on Computing 1736:{\displaystyle O(\log n)} 1215:{\displaystyle O(\log p)} 1180:{\displaystyle O(\log n)} 83:max-flow min-cut theorems 2161:10.1109/tit.1987.1057290 1743:-factor for every graph 1630:Forwarding index problem 1095:approximation algorithms 1077:{\displaystyle \varphi } 976:{\displaystyle \varphi } 870:{\displaystyle \varphi } 758:{\displaystyle \varphi } 616:{\displaystyle \varphi } 370:{\displaystyle \varphi } 307:is the maximum value of 293:Ford–Fulkerson algorithm 95:approximation algorithms 1511:′ â‰¤ 1/3 1501:′ <  1398:{\displaystyle \pi (U)} 1265:{\displaystyle G=(V,E)} 1144:{\displaystyle G=(V,E)} 451:{\displaystyle G=(V,E)} 2174:Tragoudas, S. (1990). 1826: 1737: 1698: 1663: 1620: 1569: 1486: 1432:-balanced cut of size 1421:-balanced cut of size 1399: 1370: 1266: 1216: 1181: 1145: 1101:problems, such as the 1078: 1054: 977: 953: 871: 847: 759: 735: 669: 617: 565: 494: 493:{\displaystyle u\in V} 452: 414: 413:{\displaystyle v\in V} 371: 339: 277: 250: 219: 192: 165: 138: 101:and related problems. 2201:Mathematical theorems 1973:10.1287/opre.11.3.344 1933:10.1145/331524.331526 1827: 1738: 1699: 1697:{\displaystyle K_{n}} 1664: 1662:{\displaystyle K_{n}} 1621: 1570: 1487: 1400: 1371: 1282:,1 −  1267: 1217: 1182: 1146: 1079: 1055: 978: 954: 872: 848: 760: 736: 670: 618: 566: 495: 453: 415: 372: 340: 278: 276:{\displaystyle t_{i}} 251: 249:{\displaystyle s_{i}} 220: 193: 191:{\displaystyle D_{i}} 166: 164:{\displaystyle t_{i}} 139: 137:{\displaystyle s_{i}} 2196:Network flow problem 1759: 1751:Planar edge deletion 1712: 1681: 1646: 1642:and an embedding of 1588: 1579:VLSI layout problems 1517: 1436: 1380: 1303: 1238: 1191: 1156: 1117: 1068: 1064:is the max-flow and 1006: 967: 963:is the max-flow and 905: 861: 857:is the max-flow and 799: 749: 745:is the max-flow and 687: 627: 607: 547: 478: 424: 398: 361: 319: 299:Max-flow and min-cut 289:maximum flow problem 260: 233: 202: 175: 148: 121: 81:theory. Approximate 2040:10.1145/77600.77620 1960:Operations Research 564:{\displaystyle 1/k} 345:units of commodity 291:. According to the 225:units of commodity 2026:Journal of the ACM 1910:Journal of the ACM 1822: 1733: 1694: 1659: 1616: 1565: 1482: 1409:. This is also an 1395: 1366: 1262: 1212: 1177: 1141: 1074: 1050: 973: 949: 867: 843: 755: 731: 665: 613: 561: 510:Linear programming 490: 448: 410: 367: 335: 273: 246: 215: 188: 161: 134: 1815: 1796: 1559: 1464: 1425:, then we find a 1032: 931: 825: 713: 659: 332: 212: 89:("min-cut") in a 72: 71: 64: 2208: 2180: 2179: 2171: 2165: 2164: 2142: 2136: 2135: 2127: 2121: 2120: 2112: 2106: 2105: 2083: 2074: 2073: 2059: 2053: 2052: 2042: 2017:Matula, David W. 2012: 2006: 2005: 1983: 1977: 1976: 1951: 1945: 1944: 1926: 1904: 1854: 1850: 1843: 1839: 1835: 1831: 1829: 1828: 1823: 1821: 1817: 1816: 1808: 1797: 1789: 1746: 1742: 1740: 1739: 1734: 1707: 1703: 1701: 1700: 1695: 1693: 1692: 1675:forwarding index 1672: 1668: 1666: 1665: 1660: 1658: 1657: 1641: 1637: 1625: 1623: 1622: 1617: 1606: 1605: 1574: 1572: 1571: 1566: 1564: 1560: 1558: 1557: 1542: 1528: 1512: 1505: 1495: 1491: 1489: 1488: 1483: 1481: 1477: 1476: 1465: 1457: 1431: 1424: 1420: 1416: 1408: 1404: 1402: 1401: 1396: 1375: 1373: 1372: 1367: 1298: 1297: â‰¤ 1/2 1287: 1271: 1269: 1268: 1263: 1225: 1221: 1219: 1218: 1213: 1186: 1184: 1183: 1178: 1150: 1148: 1147: 1142: 1083: 1081: 1080: 1075: 1063: 1059: 1057: 1056: 1051: 1037: 1033: 1031: 1017: 1001: 982: 980: 979: 974: 962: 958: 956: 955: 950: 936: 932: 930: 916: 900: 876: 874: 873: 868: 856: 852: 850: 849: 844: 830: 826: 824: 810: 794: 764: 762: 761: 756: 744: 740: 738: 737: 732: 718: 714: 712: 698: 674: 672: 671: 666: 664: 660: 658: 644: 622: 620: 619: 614: 602: 598: 594: 570: 568: 567: 562: 557: 542: 521: 517: 499: 497: 496: 491: 473: 469: 465: 461: 457: 455: 454: 449: 419: 417: 416: 411: 376: 374: 373: 368: 352: 348: 344: 342: 341: 336: 334: 333: 330: 314: 310: 286: 282: 280: 279: 274: 272: 271: 255: 253: 252: 247: 245: 244: 228: 224: 222: 221: 216: 214: 213: 210: 197: 195: 194: 189: 187: 186: 170: 168: 167: 162: 160: 159: 143: 141: 140: 135: 133: 132: 116: 67: 60: 56: 53: 47: 27: 26: 19: 2216: 2215: 2211: 2210: 2209: 2207: 2206: 2205: 2186: 2185: 2184: 2183: 2173: 2172: 2168: 2144: 2143: 2139: 2129: 2128: 2124: 2114: 2113: 2109: 2085: 2084: 2077: 2061: 2060: 2056: 2015:Shahrokri, F.; 2014: 2013: 2009: 1985: 1984: 1980: 1953: 1952: 1948: 1924:10.1.1.640.2995 1906: 1905: 1866: 1861: 1852: 1848: 1841: 1837: 1833: 1769: 1765: 1757: 1756: 1753: 1744: 1710: 1709: 1705: 1684: 1679: 1678: 1670: 1649: 1644: 1643: 1639: 1635: 1632: 1626:times optimal. 1597: 1586: 1585: 1581: 1550: 1543: 1529: 1523: 1515: 1514: 1507: 1497: 1493: 1469: 1446: 1442: 1434: 1433: 1426: 1422: 1418: 1414: 1406: 1378: 1377: 1301: 1300: 1293: 1277: 1236: 1235: 1232: 1223: 1189: 1188: 1154: 1153: 1115: 1114: 1111: 1103:graph partition 1091: 1066: 1065: 1061: 1021: 1012: 1004: 1003: 999: 965: 964: 960: 920: 911: 903: 902: 898: 887: 859: 858: 854: 814: 805: 797: 796: 792: 785: 747: 746: 742: 702: 693: 685: 684: 648: 639: 625: 624: 605: 604: 600: 596: 592: 582: 577: 545: 544: 540: 528: 519: 515: 512: 506: 476: 475: 471: 467: 463: 459: 422: 421: 396: 395: 392: 383: 359: 358: 350: 346: 325: 317: 316: 312: 308: 301: 284: 263: 258: 257: 236: 231: 230: 226: 205: 200: 199: 178: 173: 172: 151: 146: 145: 124: 119: 118: 114: 107: 99:graph partition 68: 57: 51: 48: 40:help improve it 37: 28: 24: 17: 12: 11: 5: 2214: 2212: 2204: 2203: 2198: 2188: 2187: 2182: 2181: 2166: 2155:(2): 224–232. 2137: 2122: 2107: 2096:(2): 235–251. 2075: 2054: 2033:(2): 318–334. 2007: 1978: 1967:(3): 344–360. 1946: 1917:(6): 787–832. 1863: 1862: 1860: 1857: 1820: 1814: 1811: 1806: 1803: 1800: 1795: 1792: 1787: 1784: 1781: 1778: 1775: 1772: 1768: 1764: 1752: 1749: 1732: 1729: 1726: 1723: 1720: 1717: 1691: 1687: 1656: 1652: 1631: 1628: 1615: 1612: 1609: 1604: 1600: 1596: 1593: 1580: 1577: 1563: 1556: 1553: 1549: 1546: 1541: 1538: 1535: 1532: 1526: 1522: 1480: 1475: 1472: 1468: 1463: 1460: 1455: 1452: 1449: 1445: 1441: 1394: 1391: 1388: 1385: 1365: 1362: 1359: 1356: 1353: 1350: 1347: 1344: 1341: 1338: 1335: 1332: 1329: 1326: 1323: 1320: 1317: 1314: 1311: 1308: 1261: 1258: 1255: 1252: 1249: 1246: 1243: 1231: 1228: 1211: 1208: 1205: 1202: 1199: 1196: 1176: 1173: 1170: 1167: 1164: 1161: 1140: 1137: 1134: 1131: 1128: 1125: 1122: 1110: 1107: 1090: 1087: 1073: 1049: 1046: 1043: 1040: 1036: 1030: 1027: 1024: 1020: 1015: 1011: 972: 948: 945: 942: 939: 935: 929: 926: 923: 919: 914: 910: 886: 883: 866: 842: 839: 836: 833: 829: 823: 820: 817: 813: 808: 804: 784: 781: 754: 730: 727: 724: 721: 717: 711: 708: 705: 701: 696: 692: 663: 657: 654: 651: 647: 642: 638: 635: 632: 612: 595:, there is an 581: 578: 576: 573: 560: 556: 552: 527: 524: 505: 502: 489: 486: 483: 447: 444: 441: 438: 435: 432: 429: 409: 406: 403: 391: 388: 382: 379: 366: 328: 324: 300: 297: 270: 266: 243: 239: 208: 185: 181: 158: 154: 131: 127: 106: 103: 70: 69: 31: 29: 22: 15: 13: 10: 9: 6: 4: 3: 2: 2213: 2202: 2199: 2197: 2194: 2193: 2191: 2177: 2170: 2167: 2162: 2158: 2154: 2150: 2149: 2141: 2138: 2133: 2126: 2123: 2118: 2111: 2108: 2103: 2099: 2095: 2091: 2090: 2082: 2080: 2076: 2071: 2067: 2066: 2065:J. Algorithms 2058: 2055: 2050: 2046: 2041: 2036: 2032: 2028: 2027: 2022: 2018: 2011: 2008: 2003: 1999: 1995: 1991: 1990: 1982: 1979: 1974: 1970: 1966: 1962: 1961: 1956: 1950: 1947: 1942: 1938: 1934: 1930: 1925: 1920: 1916: 1912: 1911: 1903: 1901: 1899: 1897: 1895: 1893: 1891: 1889: 1887: 1885: 1883: 1881: 1879: 1877: 1875: 1873: 1871: 1869: 1865: 1858: 1856: 1847: 1818: 1812: 1809: 1804: 1801: 1793: 1790: 1785: 1782: 1779: 1776: 1773: 1766: 1762: 1750: 1748: 1727: 1724: 1721: 1715: 1689: 1685: 1676: 1654: 1650: 1629: 1627: 1610: 1607: 1602: 1598: 1591: 1578: 1576: 1561: 1554: 1551: 1547: 1544: 1539: 1536: 1533: 1530: 1524: 1520: 1510: 1504: 1500: 1478: 1473: 1470: 1466: 1461: 1458: 1453: 1450: 1447: 1443: 1439: 1429: 1412: 1389: 1383: 1360: 1354: 1348: 1345: 1342: 1336: 1330: 1324: 1321: 1315: 1309: 1306: 1296: 1291: 1285: 1281: 1275: 1256: 1253: 1250: 1244: 1241: 1229: 1227: 1222:factor where 1206: 1203: 1200: 1194: 1171: 1168: 1165: 1159: 1135: 1132: 1129: 1123: 1120: 1109:Sparsest cuts 1108: 1106: 1104: 1100: 1096: 1088: 1086: 1085: 1071: 1047: 1044: 1041: 1038: 1034: 1028: 1025: 1022: 1018: 1013: 1002:commodities, 996: 992: 989: 985: 984: 970: 946: 943: 940: 937: 933: 927: 924: 921: 917: 912: 895: 891: 884: 882: 879: 878: 864: 840: 837: 834: 831: 827: 821: 818: 815: 811: 806: 795:commodities, 789: 782: 780: 777: 774: 771: 767: 766: 752: 728: 725: 722: 719: 715: 709: 706: 703: 699: 694: 681: 677: 676: 661: 655: 652: 649: 645: 640: 636: 633: 630: 610: 589: 585: 579: 574: 572: 558: 554: 550: 537: 534: 525: 523: 511: 503: 501: 487: 484: 481: 442: 439: 436: 430: 427: 407: 404: 401: 389: 387: 380: 378: 364: 356: 326: 322: 306: 298: 296: 294: 290: 268: 264: 241: 237: 206: 183: 179: 171:, and demand 156: 152: 129: 125: 112: 104: 102: 100: 96: 92: 88: 84: 80: 76: 66: 63: 55: 45: 41: 35: 32:This article 30: 21: 20: 2175: 2169: 2152: 2146: 2140: 2131: 2125: 2116: 2110: 2093: 2087: 2069: 2063: 2057: 2030: 2024: 2010: 1993: 1987: 1981: 1964: 1958: 1949: 1914: 1908: 1754: 1674: 1638:-node graph 1633: 1582: 1508: 1502: 1498: 1427: 1294: 1289: 1283: 1279: 1273: 1233: 1112: 1092: 997: 994: 993: 990: 986: 896: 893: 892: 888: 880: 790: 787: 786: 778: 775: 772: 768: 682: 679: 678: 603:and min-cut 590: 587: 586: 583: 538: 529: 513: 393: 384: 354: 304: 302: 108: 79:network flow 74: 73: 58: 52:January 2016 49: 33: 97:for use in 87:minimum cut 2190:Categories 2134:: 422–431. 2119:: 691–697. 2072:: 241–269. 1859:References 1274:b-balanced 995:Theorem 5. 894:Theorem 4. 788:Theorem 3. 680:Theorem 2. 623:for which 588:Theorem 1. 508:See also: 1996:: 75–81. 1955:Hu, T. C. 1919:CiteSeerX 1805:⁡ 1780:⁡ 1725:⁡ 1634:Given an 1608:⁡ 1548:− 1537:⁡ 1467:− 1454:⁡ 1384:π 1355:π 1346:− 1337:≤ 1325:π 1322:≤ 1310:π 1290:separator 1204:⁡ 1169:⁡ 1072:φ 1048:φ 1045:≤ 1039:≤ 1026:⁡ 1019:φ 1010:Ω 971:φ 947:φ 944:≤ 938:≤ 925:⁡ 918:φ 909:Ω 865:φ 841:φ 838:≤ 832:≤ 819:⁡ 812:φ 803:Ω 753:φ 729:φ 726:≤ 720:≤ 707:⁡ 700:φ 691:Ω 653:⁡ 646:φ 634:≤ 611:φ 485:∈ 470:and node 420:in graph 405:∈ 365:φ 283:for each 2019:(1990). 1941:18527968 1555:′ 1492:for any 1474:′ 1060:, where 959:, where 853:, where 741:, where 591:For any 311:, where 305:max-flow 2049:4469579 1846:polylog 1430:′ 1411:NP-hard 1099:NP-hard 901:nodes, 526:History 355:min-cut 144:, sink 38:Please 2047:  1939:  1921:  1496:where 1417:has a 1376:where 533:Matula 2045:S2CID 1937:S2CID 1299:) if 1292:(for 1276:or a 229:from 111:nodes 1506:and 1097:for 462:and 2157:doi 2098:doi 2035:doi 1998:doi 1969:doi 1929:doi 1802:log 1777:log 1722:log 1669:in 1599:log 1534:log 1451:log 1201:log 1166:log 1023:log 922:log 816:log 704:log 650:log 256:to 115:k≥1 42:to 2192:: 2153:33 2151:. 2094:25 2092:. 2078:^ 2070:22 2068:. 2043:. 2031:37 2029:. 2023:. 1994:31 1992:. 1965:11 1963:. 1935:. 1927:. 1915:46 1913:. 1867:^ 1855:. 1747:. 1575:. 1494:b' 500:. 2163:. 2159:: 2104:. 2100:: 2051:. 2037:: 2004:. 2000:: 1975:. 1971:: 1943:. 1931:: 1853:R 1849:n 1842:G 1838:R 1834:G 1819:) 1813:R 1810:n 1799:) 1794:R 1791:n 1786:+ 1783:n 1774:R 1771:( 1767:( 1763:O 1745:G 1731:) 1728:n 1719:( 1716:O 1706:G 1690:n 1686:K 1671:G 1655:n 1651:K 1640:G 1636:n 1614:) 1611:n 1603:6 1595:( 1592:O 1562:) 1552:b 1545:b 1540:n 1531:S 1525:( 1521:O 1509:b 1503:b 1499:b 1479:) 1471:b 1462:b 1459:n 1448:S 1444:( 1440:O 1428:b 1423:S 1419:b 1415:G 1407:U 1393:) 1390:U 1387:( 1364:) 1361:V 1358:( 1352:) 1349:b 1343:1 1340:( 1334:) 1331:U 1328:( 1319:) 1316:V 1313:( 1307:b 1295:b 1288:- 1286:) 1284:b 1280:b 1278:( 1260:) 1257:E 1254:, 1251:V 1248:( 1245:= 1242:G 1224:p 1210:) 1207:p 1198:( 1195:O 1175:) 1172:n 1163:( 1160:O 1139:) 1136:E 1133:, 1130:V 1127:( 1124:= 1121:G 1062:f 1042:f 1035:) 1029:k 1014:( 1000:k 961:f 941:f 934:) 928:n 913:( 899:n 855:f 835:f 828:) 822:k 807:( 793:k 743:f 723:f 716:) 710:n 695:( 675:. 662:) 656:n 641:( 637:O 631:f 601:f 597:n 593:n 559:k 555:/ 551:1 541:k 520:G 516:G 488:V 482:u 472:v 468:u 464:v 460:u 446:) 443:E 440:, 437:V 434:( 431:= 428:G 408:V 402:v 351:i 347:i 331:i 327:D 323:f 313:f 309:f 285:i 269:i 265:t 242:i 238:s 227:i 211:i 207:D 184:i 180:D 157:i 153:t 130:i 126:s 65:) 59:( 54:) 50:( 36:.

Index

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network flow
max-flow min-cut theorems
minimum cut
multi-commodity flow problem
approximation algorithms
graph partition
nodes
maximum flow problem
Ford–Fulkerson algorithm
Linear programming
Matula
approximation algorithms
NP-hard
graph partition
NP-hard
polylog










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