Tutte polynomial, subgraphs, orientations and sandpile model: new connections via embeddings.
Underlying Graphs of 3-Quasi-Transitive Digraphs and 3-Transitive Digraphs
A digraph is 3-quasi-transitive (resp. 3-transitive), if for any path x0x1 x2x3 of length 3, x0 and x3 are adjacent (resp. x0 dominates x3). C´esar Hern´andez-Cruz conjectured that if D is a 3-quasi-transitive digraph, then the underlying graph of D, UG(D), admits a 3-transitive orientation. In this paper, we shall prove that the conjecture is true.
Undirected strict gammoids
Uniquely realizable score lists in bipartite tournaments
Universality of directed graphs of a given height
Unordered love in infinite directed graphs.
Upper signed total domination number of directed graphs
Utilisation des scores dans des méthodes exactes déterminant les ordres médians de tournois
Dans cet article, nous utilisons un paramètre défini à partir des scores d’un tournoi pour déterminer les ordres médians de . Ce paramètre évalue un éloignement entre le tournoi et les tournois transitifs ayant le même nombre de sommets. Appelant le nombre minimum d’arcs à inverser pour rendre transitif, et le nombre de sommets de , nous proposons d’abord deux algorithmes linéaires en n calculant et un ordre médian de pour les tournois tels que soit égal à ou . Puis nous...
Vertex-oriented Hamilton cycles in directed graphs.
Which directed graphs have a solution?
Zerlegung total gerichteter Graphen in Kreise.
Zyklische Orientierungen endlicher bewerteter Graphen.
γ-Cycles And Transitivity By Monochromatic Paths In Arc-Coloured Digraphs
We call the digraph D an m-coloured digraph if its arcs are coloured with m colours. If D is an m-coloured digraph and a ∈ A(D), colour(a) will denote the colour has been used on a. A path (or a cycle) is called monochromatic if all of its arcs are coloured alike. A γ-cycle in D is a sequence of vertices, say γ = (u0, u1, . . . , un), such that ui ≠ uj if i ≠ j and for every i ∈ 0, 1, . . . , n there is a uiui+1-monochromatic path in D and there is no ui+1ui-monochromatic path in D (the indices...
γ-Cycles In Arc-Colored Digraphs
We call a digraph D an m-colored digraph if the arcs of D are colored with m colors. A directed path (or a directed cycle) is called monochromatic if all of its arcs are colored alike. A subdigraph H in D is called rainbow if all of its arcs have different colors. A set N ⊆ V (D) is said to be a kernel by monochromatic paths of D if it satisfies the two following conditions: for every pair of different vertices u, v ∈ N there is no monochromatic path in D between them, and for every vertex x ∈ V...
Информационные графы.
Комбинаторная характеристика конечных базисоов чистых свободных полугрупп
Об одном соотношении в конечных топологиях
Обобщенное соответствие Робинсона-Шенстеда-Кнута
Представление поликолчанов ручного типа
Свободные произведения сеток и свободные симметризаторы графов