Now showing items 21-40 of 112

• #### Aplicaciones de la teoría de grafos al diseño de redes de interconexión de multiprocesadores ﻿

(Universitat Politècnica de Catalunya, 1982-01-01)
Doctoral thesis
Open Access
En este trabajo se estudia, mediante la Teoría de Grafos, el diseño de redes de interconexión para sistemas distribuidos. Los principales temas tratados son: 1. Se propone una metodología general para la obtención de redes ...
• #### Aplicaciones de la Teoría de Matrices en Matemática Discreta ﻿

(1999-07)
Working paper
Open Access
Se describen algunas aplicaciones de la teoría de matrices a diversos temas pertenecientes al ámbito de la matem\'atica discreta.
• #### A simple proof of the spectral excess theorem for distance-regular graphs ﻿

(Elsevier, 2010-04-15)
Article
Restricted access - publisher's policy
The spectral excess theorem provides a quasi-spectral characterization for a (regular) graph Γ with d+1 distinct eigenvalues to be distance-regular graph, in terms of the excess (number of vertices at distance d) of each ...
• #### Caracterizaciones combinatorias y algebraicas de grafos distancia-regulares ﻿

(Universitat Rovira i Virgili, 2014)
Conference report
Open Access
Los grafos distancia-regulares aparecen a menudo en el estudio de es- tructuras matemáticas con un alto grado de simetría y/o regularidad. Un ejemplo bien conocido de tales grafos son los esqueletos ...
• #### Caracterizaciones combinatorias y algebraicas de grafos distancia-regulares ﻿

Part of book or chapter of book
Restricted access - publisher's policy
Los grafos distancia-regulares aparecen a menudo en el estudio de estructuras matemáticas con un alto grado de simetría y/o regularidad. Un ejemplo bien conocido de tales grafos son los esqueletos de los sólidos platónicos. ...
• #### c-Critical graphs with maximum degree three ﻿

(John Wiley and Sons, Inc., 1995)
Part of book or chapter of book
Restricted access - publisher's policy
Let $G$ be a (simple) gtoph with maximum degree three and chromatic index four. A 3-edge-coloring of G is a coloring of its edges in which only three colors are used. Then a vertex is conflicting when some edges incident ...
• #### c-Critical graphs with maximum degree three ﻿

(Wiley, 1995-06)
Part of book or chapter of book
Restricted access - publisher's policy
Let G be a (simple) graph with maximum degree three and chromatic index four. A 3-edge-coloring of G is a coloring of its edges in which only three colors are used. Then a vertex is conflicting when some edges incident to ...
• #### Characterizing (l,m)-walk-regularity ﻿

(2009-05)
Article
Open Access
A graph $\G$ with diameter $D$ and $d+1$ distinct eigenvalues is said to be {\it $(\ell,m)$-walk-regular}, for some integers $\ell\in[0,d]$ and $m\in[0,D]$, $\ell\ge m$, if the number of walks of length $i\in [0,\ell]$ ...
• #### Ciclos de Hamilton en redes de paso commutativo y de paso fijo ﻿

Article
Open Access
From a natural generalization to $Z^2$ of the concept of congruence, it is possible to define a family of $2$-regular digraphs that we call "commutative-step networks". Particular examples of such digraphs are the Cartesian ...
• #### Coloración de grafos ﻿

(2000-05)
Article
Open Access
Estudiamos algunos resultados sobre rama-coloración de grafos y su relación con el teorema del mapa de cuatro colores. A tal fin, se introduce la noción de “coloración” de una conjunto de ramas y se estudian sus propiedades ...
• #### Combinatorial vs. algebraic characterizations of pseudo-distance-regularity around a set ﻿

(2009-06)
External research report
Open Access
Given a simple connected graph $\Gamma$ and a subset of its vertices $C$, the pseudo-distance-regularity around $C$ generalizes, for not necessarily regular graphs, the notion of completely regular code. Up to now, most ...
• #### Comments on “Extremal Cayley Digraphs of Finite Abelian Groups” [Intercon. Networks 12 (2011), no. 1-2, 125–135] ﻿

(2013-12)
Article
Open Access
We comment on the paper “Extremal Cayley digraphs of finite Abelian groups” [Intercon. Networks 12 (2011), no. 1-2, 125–135]. In particular, we give some counterexamples to the results presented there, and provide a correct ...
• #### Connectivity: properties and structure ﻿

(CRC Press Taylor & Francis Group, 2013-12-05)
Part of book or chapter of book
Open Access
Connectivity is one of the central concepts of graph theory, from both a theoret- ical and a practical point of view. Its theoretical implications are mainly based on the existence of nice max-min characterization results, ...

(2014)
Article
Open Access
• #### Cospectral digraphs from locally line digraphs ﻿

(Elsevier, 2016-07-01)
Article
Restricted access - publisher's policy
A digraph Gamma = (V, E) is a line digraph when every pair of vertices u, v is an element of V have either equal or disjoint in -neighborhoods. When this condition only applies for vertices in a given subset (with at least ...
• #### Deterministic hierarchical networks ﻿

(2007-11-20)
Article
Open Access
Recently it has been shown that many networks associated with complex systems are small-world (they have both a large local clustering and a small diameter) and they are also scale-free (the degrees are distributed according ...
• #### Deterministic hierarchical networks ﻿

(2016)
Article
Open Access
It has been shown that many networks associated with complex systems are small-world (they have both a large local clustering coefficient and a small diameter) and also scale-free (the degrees are distributed according ...
• #### Digraphs with walks of equal length between vertices ﻿

(1984)
Conference report
Open Access
• #### Distance mean-regular graphs ﻿

(2016)
Article
Open Access
We introduce the concept of distance mean-regular graph, which can be seen as a generalization of both vertex-transitive and distance-regular graphs. Let G be a graph with vertex set V , diameter D, adjacency matrix A, and ...
• #### Distance-regular graphs where the distance-d graph has fewer distinct eigenvalues ﻿

(Elsevier, 2015)
Article
Open Access
Let the Kneser graph K of a distance-regular graph $\Gamma$ be the graph on the same vertex set as $\Gamma$, where two vertices are adjacent when they have maximal distance in $\Gamma$. We study the situation where the ...