3 papers
math.CO2008
Transitive orientations in bull-reducible Berge graphs
Celina de Figueiredo, Frederic Maffray, Claudia Villela Maciel
A bull is a graph with five vertices and five edges , , , , . A graph is bull-reducible if no vertex of lies in two bulls. We prove that…
cs.DM2007
On b-perfect chordal graphs
Frédéric Maffray, Meriem Mechebbek
The b-chromatic number of a graph G is the largest integer k such that G has a coloring of the vertices in k color classes such that every color class contains a vertex that has a…
cs.DM2007
Maximum directed cuts in digraphs with degree restriction
Jenö Lehel, Frédéric Maffray, Myriam Preissmann
For integers m,k >= 1, we investigate the maximum size of a directed cut in directed graphs in which there are m edges and each vertex has either indegree at most k or outdegree at…