科研之友
微信
新浪微博
Facebook
分享链接
摘要
Let G = (V, E) be a nonseparable plane graph on n vertices with at least two edges. Suppose that G has outer face C and that every 2-vertex-cut of G contains at least one vertex of C. Let P-G(q) denote the chromatic polynomial of G. We show that (-1)P-n(G)(q) > 0 for all 1 < q <= 1.2040.... This result is a corollary of a more general result that (-1)(n)Z(G)(q, w) > 0 for all 1 < q <= 1.2040 ..., where Z(G)(q, w) is the multivariate Tutte polynomial of G, w = {w(e)}(e is an element of E), w(e) = -1 for all e which are not incident to a vertex of C, w(e) is an e
- 出版日期2011
- 单位南阳理工学院
