文摘
A graph has a perfect matching if and only if is not a root of its matching polynomial . Thus, Tutte¡¯s famous theorem asserts that is not a root of if and only if for all , where denotes the number of odd components of . Tutte¡¯s theorem can be proved using a characterization of the structure of maximal non-matchable graphs, that is, the edge-maximal graphs among those having no perfect matching. In this paper, we prove a generalized version of Tutte¡¯s theorem in terms of avoiding any given real number as a root of . We also extend maximal non-matchable graphs to maximal -non-matchable graphs and determine the structure of such graphs.