给G=(V,E)的每个顶点分配一个色列表L={L(v)|v∈V},若G有一个正常顶点染色φ,使得对每个顶点v∈V,都有φ(v)∈L(v),则称G是L可染的。若对G的每一个满足|L(v)|≥k,v∈V的L,G都是L可染的,则称G是k可选择的。本文通过权转移方法证明了每个不含4,6,8,10圈的可平面图是3可选择的。
Assigning each vertex of G=(V,E) a list L={L(v)|v∈V},if G has a proper coloring φ such that φ(v)∈L(v) for every vertex v,then we say that G is L-colorable.A graph G is k-choosable,if it is L-colorable for every list assignment L with |L(v)|≥k for all v∈V.According to the discharging,it is shown that every planar graph without 4-,6-,8-or 10-cycles is 3-choosable.