On Structure of Some Plane Graphs with Application to Choosability

نویسندگان

  • Peter Che Bor Lam
  • Wai Chee Shiu
  • Baogang Xu
چکیده

A graph G=(V, E) is (x, y)-choosable for integers x> y 1 if for any given family [A(v) | v # V] of sets A(v) of cardinality x, there exists a collection [B(v) | v # V] of subsets B(v)/A(v) of cardinality y such that B(u) & B(v)=< whenever uv # E(G). In this paper, structures of some plane graphs, including plane graphs with minimum degree 4, are studied. Using these results, we may show that if G is free of k-cycles for some k # [3, 4, 5, 6], or if any two triangles in G have distance at least 2, then G is (4m, m)-choosable for all nonnegative integers m. When m=1, (4m, m)-choosable is simply 4-choosable. So these conditions are also sufficient for a plane graph to be 4-choosable. 2001 Academic Press

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عنوان ژورنال:
  • J. Comb. Theory, Ser. B

دوره 82  شماره 

صفحات  -

تاریخ انتشار 2001