文摘
A graph is called super-Eulerian if it has a spanning closed trail. Let be a graph with vertices. Catlin in (1987)? proved that if for each edge , then has a spanning trail except for several defined graphs. In this work we prove that if for each edge , then is collapsible except for several special graphs, which strengthens the result of Catlin¡¯s, where for even and for odd. As corollaries, a characterization for graphs satisfying for each edge to be super-Eulerian is obtained; by using a theorem of Harary and Nash-Williams, the works here also imply the previous results in? by Brualdi and Shanny (1981), and in? by Clark (1984).