证明了每个围长至少是4且不合6-圈,9-圈和10-圈的平面图是3-可选择的.
lain proved that every planar graph with girth at least 4 and without 5-and 6- cycle is 3-choosable. It is shown that if G is of girth 4 and contains no 6-, 9-, and 10-cycles, then G is 3-choosable.