Exploració per autor "Fiol Mora, Miquel Àngel"
Ara es mostren els items 21-40 de 139
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An algebraic approach to lifts of digraphs
(2019-09)
Article
Accés obertWe study the relationship between two key concepts in the theory of (di)graphs: the quotient digraph, and the lift Ga of a base (voltage) digraph. These techniques contract or expand a given digraph in order to study its ... -
An algebraic model for the storage of data in parallel memories
(Springer, 1989)
Capítol de llibre
Accés obertThe use of SIMD computers requires efficient schemes of storage of data in order to have conflict-free acces in parallel computation. In this paper we restate the problem of finding such chemes in an algebraic context. ... -
An eigenvalue characterization of antipodal distance-regular graphs
(1997-11)
Article
Accés obertLet $\Gamma$ be a regular (connected) graph with $n$ vertices and $d+1$ distinct eigenvalues. As a main result, it is shown that $\Gamma$ is an $r$-antipodal distance-regular graph if and only if the distance graph $\Gamma_d$ ... -
An improved Moore bound and some new optimal families of mixed Abelian Cayley graphs
(2020-10)
Article
Accés obertWe consider the case in which mixed graphs (with both directed and undirected edges) are Cayley graphs of Abelian groups. In this case, some Moore bounds were derived for the maximum number of vertices that such graphs can ... -
An improved upper bound for the order of mixed graphs
(2018-07)
Article
Accés obertA mixed graph G can contain both (undirected) edges and arcs (directed edges). Here we derive an improved Moore-like bound for the maximum number of vertices of a mixed graph with diameter at least three. Moreover, a ... -
An interlacing approach for bounding the sum of Laplacian eigenvalues of graphs
(2014)
Text en actes de congrés
Accés obertWe apply eigenvalue interlacing techniques for obtaining lower and upper bounds for the sums of Laplacian eigenvalues of graphs, and characterize equality. This leads to generalizations of, and variations on theorems by ... -
Aplicaciones de la teoría de grafos al diseño de redes de interconexión de multiprocesadores
(Universitat Politècnica de Catalunya, 1982-01-01)
Tesi
Accés obertEn 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
Accés obertSe describen algunas aplicaciones de la teoría de matrices a diversos temas pertenecientes al ámbito de la matem\'atica discreta. -
Bipartite biregular Moore graphs
(2021-11)
Article
Accés obertA bipartite graph G = (V, E) with V = V1 ¿ V2 is biregular if all the vertices of a stable set Vi have the same degree ri for i = 1, 2. In this paper, we give an improved new Moore bound for an infinite family of such ... -
c-Critical graphs with maximum degree three
(Wiley, 1995-06)
Capítol de llibre
Accés restringit per política de l'editorialLet 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 ... -
c-Critical graphs with maximum degree three
(John Wiley and Sons, Inc., 1995)
Capítol de llibre
Accés restringit per política de l'editorialLet $G$ 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 ... -
Caracterizaciones combinatorias y algebraicas de grafos distancia-regulares
(Universitat Rovira i Virgili, 2014)
Text en actes de congrés
Accés obertLos 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
(Universidad de Cádiz, 2013)
Capítol de llibre
Accés restringit per política de l'editorialLos 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. ... -
Characterizing (l,m)-walk-regularity
(2009-05)
Article
Accés obertA 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
(Universidad de Barcelona, Departamento de Estadística Matemática;Universidad Politécnica de Barcelona, Escuela Técnica Superior de Arquitectura, Departamento de Matemáticas y Estadística, 1988)
Article
Accés obertFrom 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 ... -
Ciclos de Hamilton en redes de pasos commutativos y de paso fijo
(1988)
Article
Accés obertFrom a natural generalization to Z2 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 product ... -
Coloración de grafos
(2000-05)
Article
Accés obertEstudiamos 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)
Report de recerca
Accés obertGiven 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
Accés obertWe 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)
Capítol de llibre
Accés obertConnectivity 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, ...
