Calcul du centralisateur d'un groupe de permutations
Canonical decomposition of outerplanar maps and application to enumeration, coding and generation.
Centrally-symmetric tight surfaces and graph embeddings.
Certain cubic multigraphs and their upper embeddability
Characteristic polynomials of some weighted graph bundles and its application to links.
Characterization of semientire graphs with crossing number 2
The purpose of this paper is to give characterizations of graphs whose vertex-semientire graphs and edge-semientire graphs have crossing number 2. In addition, we establish necessary and sufficient conditions in terms of forbidden subgraphs for vertex-semientire graphs and edge-semientire graphs to have crossing number 2.
Characterizations of planar plick graphs
In this paper we present characterizations of graphs whose plick graphs are planar, outerplanar and minimally nonouterplanar.
Characterizing the maximum genus of a connected graph
Chiral hypermaps of small genus.
Chiral hypermaps with few hyperfaces
Circularity of graphs and continua: topology
Classification of -dipoles on nonorientable surfaces.
Classification of rings with toroidal Jacobson graph
Let be a commutative ring with nonzero identity and the Jacobson radical of . The Jacobson graph of , denoted by , is defined as the graph with vertex set such that two distinct vertices and are adjacent if and only if is not a unit of . The genus of a simple graph is the smallest nonnegative integer such that can be embedded into an orientable surface . In this paper, we investigate the genus number of the compact Riemann surface in which can be embedded and explicitly...
Clique-connecting forest and stable set polytopes
Let G = (V,E) be a simple undirected graph. A forest F ⊆ E of G is said to be clique-connecting if each tree of F spans a clique of G. This paper adresses the clique-connecting forest polytope. First we give a formulation and a polynomial time separation algorithm. Then we show that the nontrivial nondegenerate facets of the stable set polytope are facets of the clique-connecting polytope. Finally we introduce a family of rank inequalities which are facets, and which generalize the clique inequalities. ...
Clopen graphs
A graph G on a topological space X as its set of vertices is clopen if the edge relation of G is a clopen subset of X² without the diagonal. We study clopen graphs on Polish spaces in terms of their finite induced subgraphs and obtain information about their cochromatic numbers. In this context we investigate modular profinite graphs, a class of graphs obtained from finite graphs by taking inverse limits. This continues the investigation of continuous colorings on Polish spaces and their homogeneity...
Colorings and orientations of matrices and graphs.
Colouring vertices of plane graphs under restrictions given by faces
We consider a vertex colouring of a connected plane graph G. A colour c is used k times by a face α of G if it appears k times along the facial walk of α. We prove that every connected plane graph with minimum face degree at least 3 has a vertex colouring with four colours such that every face uses some colour an odd number of times. We conjecture that such a colouring can be done using three colours. We prove that this conjecture is true for 2-connected cubic plane graphs. Next we consider other...
Combinatorial aspects of an exact sequence that is related to a graphs.
Combinatorics of orientation reversing polygons.
Compact compatible topologies for graphs with small cycles.