Displaying similar documents to “On the number of dissimilar pfaffian orientations of graphs”

Several results on chordal bipartite graphs

Mihály Bakonyi, Aaron Bono (1997)

Czechoslovak Mathematical Journal

Similarity:

The question of generalizing results involving chordal graphs to similar concepts for chordal bipartite graphs is addressed. First, it is found that the removal of a bisimplicial edge from a chordal bipartite graph produces a chordal bipartite graph. As consequence, occurance of arithmetic zeros will not terminate perfect Gaussian elimination on sparse matrices having associated a chordal bipartite graph. Next, a property concerning minimal edge separators is presented. Finally, it is...

On a generalization of perfect b -matching

Ľubica Šándorová, Marián Trenkler (1991)

Mathematica Bohemica

Similarity:

The paper is concerned with the existence of non-negative or positive solutions to A f = β , where A is the vertex-edge incidence matrix of an undirected graph. The paper gives necessary and sufficient conditions for the existence of such a solution.