La comparaison des hiérarchies : indices et métriques
On considère un graphe complet dont les arêtes sont totalement préordonnées. En analyse de similitude, plutôt que de procéder à un ordonnancement des arêtes ex oequo par une méthode lexicographique sur leurs intitulés, l'auteur propose de rechercher la réunion des arbres maximaux (RAM).
The main focus of combinatorial dynamics is put on the structure of periodic points (and the corresponding orbits) of topological dynamical systems. The first result in this area is the famous Sharkovsky's theorem which completely describes the coexistence of periods of periodic points for a continuous map from the closed unit interval to itself. One feature of this theorem is that it can be proved using digraphs of a special type (the so-called periodic graphs). In this paper we use Markov graphs...
We prove admissible convergence to the boundary of functions that are harmonic on a subset of a non-homogeneous tree equipped with a transition operator that satisfies uniform bounds suitable for transience. The approach is based on a discrete Green formula, suitable estimates for the Green and Poisson kernel and an analogue of the Lusin area function.
>We prove that the domination number γ(T) of a tree T on n ≥ 3 vertices and with n₁ endvertices satisfies inequality γ(T) ≥ (n+2-n₁)/3 and we characterize the extremal graphs.
The open neighborhood of an edge in a graph is the set consisting of all edges having a common end-vertex with . Let be a function on , the edge set of , into the set . If for each , then is called a signed edge total dominating function of . The minimum of the values , taken over all signed edge total dominating function of , is called the signed edge total domination number of and is denoted by . Obviously, is defined only for graphs which have no connected components...