Recent Submissions

  • Green operators of networks with a new vertex 

    Carmona Mejías, Ángeles; Encinas Bachiller, Andrés Marcos; Gago Álvarez, Silvia; Mitjana Riera, Margarida (Elsevier, 2016-02)
    Article
    Open Access
    Any elliptic operator defines an automorphism on the orthogonal subspace to the eigenfunctions associated with the lowest eigenvalue, whose inverse is the orthogonal Green operator. In this study, we show that elliptic ...
  • Completion and decomposition of hypergraphs into dominating sets of graphs 

    Martí Farré, Jaume; Mora Giné, Mercè; Ruiz Muñoz, José Luis (2015-11)
    Article
    Restricted access - publisher's policy
    The collection of the vertex dominating sets of a graph defines a hypergraph on the set of vertices of the graph. However, there are hypergraphs H that are not the collection of the vertex dominating sets of any graph. ...
  • Inversa de matrices circulantes con tres parámetros 

    Mitjana Riera, Margarida (2015)
    Conference report
    Open Access
    Utilizando técnicas relacionadas con la resolución de problemas de contorno para ecuaciones en diferencias de segundo orden, se dan condiciones necesarias y suficientes cientes para la invertibilidad de matrices circulantes ...
  • Connectivity and other invariants of generalized products of graphs 

    López Masip, Susana Clara; Muntaner Batle, Francesc Antoni (2015-02-24)
    Article
    Restricted access - publisher's policy
    Figueroa-Centeno et al. [4] introduced the following product of digraphs let D be a digraph and let G be a family of digraphs such that V (F) = V for every F¿G. Consider any function h:E(D)¿G. Then the product D¿hG is the ...
  • José Gómez Martí: in memoriam 1958-2014 

    Fiol Mora, Miquel Àngel (Societat Catalana de Matemàtiques (SCM), 2015-12)
    Other
    Restricted access - publisher's policy
    La vida és el que ens passa mentre fem altres plans (John Lennon)
  • On the spectrum of the normalized Laplacian of iterated triangulations of graphs 

    Xie, Pinchen; Zhang, Zhongzhi; Comellas Padró, Francesc de Paula (2016-01-15)
    Article
    Open Access
    The eigenvalues of the normalized Laplacian of a graph provide information on its topological and structural characteristics and also on some relevant dynamical aspects, specifically in relation to random walks. In this ...
  • The inverses of some circulant matrices 

    Carmona Mejías, Ángeles; Encinas Bachiller, Andrés Marcos; Gago Álvarez, Silvia; Jiménez Jiménez, M. Jose; Mitjana Riera, Margarida (2015-11-01)
    Article
    Open Access
    We present here necessary and su cient conditions for the invertibility of circulant and symmetric matrices that depend on three parameters and moreover, we explicitly compute the inverse. The techniques we use are related ...
  • On cyclic Kautz digraphs 

    Böhmová, Katerina; Dalfó Simó, Cristina; Huemer, Clemens (2015)
    External research report
    Open Access
    A prominent problem in Graph Theory is to find extremal graphs or digraphs with restrictions in their diameter, degree and number of vertices. Here we obtain a new family of digraphs with minimal diameter, that is, given ...
  • Caracterizaciones combinatorias y algebraicas de grafos distancia-regulares 

    Fiol Mora, Miquel Àngel (Universidad de Cádiz, 2013)
    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. ...
  • Quotient-polynomial graphs 

    Fiol Mora, Miquel Àngel (Elsevier, 2016-01-01)
    Article
    Restricted access - publisher's policy
    As a generalization of orbit-polynomial and distance-regular graphs, we introduce the concept of a quotient-polynomial graph. In these graphs every vertex uinduces the same regular partition around u, where all vertices ...

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