本刊英文版Vol.27(2011),No.3论文摘要(英文)

<正>Group Connectivity and Group Colorings of Graphs—A Survey Hong-Jian LAI Xiangwen LI Yehong SHAO Mingquan ZHAN Abstract In 1950s,Tutte introduced the theory of nowhere-zero flows as a tool to investigate the coloring problem of maps,together with his most fascinating conjectures on nowhere-zero flows.These have been extended by Jaeger et al.in 1992 to group connectivity,the nonhomogeneous form of nowhere-zero flows.Let G be a 2-edge-connected undirected graph,A be an (additive) abelian group and A* = A - {0}.The graph G is A-connected if G has an orientation D(G) such that for every map b:V(G)(?) A satisfying∑_(v∈V(G)) b(v) = 0,there is a function f:E(G)(?) A* such that for each vertex v∈V(G),the total amount of f-values on the edges directed out from v minus the total amount of f-values on the edges directed into v is equal to