Einige Bemerkungen über freie Kategorien und freie Gruppoide
Either tournaments or algebras? (Preliminary communication)
El diámetro de ciertos digrafos circulantes de triple paso.
This paper studies some diameter-related properties of the 3-step circulant digraphs with set of vertices V≡ZN and steps (± a,b). More precisely, it concentrates upon maximizing their order N for any fixed value of their diameter k. In the proposed geometrical approach, each digraph is fully represented by a T-shape tile which tessellates periodically the plane. The study of these tiles leads to the optimal solutions.
Encadrement de l'indice de slater d'un tournoi à l'aide de ses scores
Dans cet article, nous définissons un paramètre à partir des scores d’un tournoi . Ce paramètre évalue un éloignement entre le tournoi et les tournois transitifs de même ordre. Appelant le nombre minimum d’arcs à inverser pour rendre transitif, nous montrons que l’on a . Nous déterminons ensuite des bornes sur la valeur maximum de pour les tournois à donné. Nous en déduisons enfin, en fonction du nombre de sommets de et de , un encadrement de l’indice de Slater d’un tournoi quelconque....
Ensembles libres de chemins dans un graphe
Enumeration of hamiltonian paths in Caley diagrams.
Équilibre, équivalence, ordre et préordre à distance minimum d'un graphe complet
Les problèmes que nous traitons ici sont en partie familiers aux lecteurs de la revue. L'apport original consiste selon nous dans le fait d'avoir rapproché des problèmes classiques (équilibre d'un graphe, ordre à distance minimum) pour en souligner les analogies profondes et, du coup, plonger de manière féconde ces problèmes dans un ensemble plus large, en particulier en posant le problème de l'équivalence et du préordre à distance minimum d'un graphe complet. Notre exposé se présente donc comme...
Establishing Order in Planar Subdivisions.
Even and odd tournament matrices with minimum rank over finite fields.
Even circuits of prescribed clockwise parity.
Every connected acyclic digraph of height 1 is neighbourhood-realizable
Explicit Cayley covers of Kautz digraphs.
Exponents of two-colored digraphs
We consider the primitive two-colored digraphs whose uncolored digraph has vertices and consists of one -cycle and one -cycle. We give bounds on the exponents and characterizations of extremal two-colored digraphs.
Extremum degree sets of irregular oriented graphs and pseudodigraphs
A digraph in which any two vertices have distinct degree pairs is called irregular. Sets of degree pairs for all irregular oriented graphs (also loopless digraphs and pseudodigraphs) with minimum and maximum size are determined. Moreover, a method of constructing corresponding irregular realizations of those sets is given.
Factoring directed graphs with respect to the cardinal product in polynomial time
By a result of McKenzie [4] finite directed graphs that satisfy certain connectivity and thinness conditions have the unique prime factorization property with respect to the cardinal product. We show that this property still holds under weaker connectivity and stronger thinness conditions. Furthermore, for such graphs the factorization can be determined in polynomial time.
Factoring directed graphs with respect to the cardinal product in polynomial time II
By a result of McKenzie [7] all finite directed graphs that satisfy certain connectivity conditions have unique prime factorizations with respect to the cardinal product. McKenzie does not provide an algorithm, and even up to now no polynomial algorithm that factors all graphs satisfying McKenzie's conditions is known. Only partial results [1,3,5] have been published, all of which depend on certain thinness conditions of the graphs to be factored. In this paper we weaken the...
Factoring polynomials in finite fields: an application of Lang-Weil to a problem in graph theory.
Families of -symplectic metrics on full flag manifolds.
Finding a Minimum-Weight k-Link Path in Graphs with the Concave Monge Property and Applications.
Finding Minimal Branchings With a Given Number of Arcs