Recent Submissions

  • José Gómez Martí 1968-2014: in memoriam 

    Fiol Mora, Miquel Àngel (Societat Catalana de Matemàtiques (SCM), 2015)
    Article
    Open Access
  • A note on the order of iterated line digraphs 

    Dalfó Simó, Cristina; Fiol Mora, Miquel Àngel (Wiley, 2016-07-27)
    Article
    Restricted access - publisher's policy
    Given a digraph G, we propose a new method to find the recurrence equation for the number of vertices n_k of the k-iterated line digraph L_k(G), for k>= 0, where L_0(G) = G. We obtain this result by using the minimal polynomial ...
  • Deterministic hierarchical networks 

    Barrière Figueroa, Eulalia; Comellas Padró, Francesc de Paula; Dalfó Simó, Cristina; Fiol Mora, Miquel Àngel (2016)
    Article
    Restricted access - publisher's policy
    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 ...
  • Cospectral digraphs from locally line digraphs 

    Dalfó Simó, Cristina; Fiol Mora, Miquel Àngel (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 ...
  • The degree/diameter problem in maximal planar bipartite graphs 

    Dalfó Simó, Cristina; Huemer, Clemens; Salas Piñon, Julián (2016)
    Article
    Open Access
    The (Δ,D)(Δ,D) (degree/diameter) problem consists of finding the largest possible number of vertices nn among all the graphs with maximum degree ΔΔ and diameter DD. We consider the (Δ,D)(Δ,D) problem for maximal planar ...
  • Perfect and quasiperfect domination in trees 

    Cáceres, José; Hernando Martín, María del Carmen; Mora Giné, Mercè; Pelayo Melero, Ignacio Manuel; Puertas, Maria Luz (2016-04-25)
    Article
    Open Access
    A k quasip erfect dominating set of a connected graph G is a vertex subset S such that every vertex not in S is adjacent to at least one and at most k vertices in S . The cardinality of a minimum k-quasip erfect dominating ...
  • On sets of vectors of a finite vector space in which every subset of basis size is a basis II 

    Ball, Simeon Michael; De Beule, Jan (2012-10)
    Article
    Open Access
    This article contains a proof of the MDS conjecture for k = 2p - 2. That is, that if S is a set of vectors of F k q in which every subset of S of size k is a basis, where q = p h, p is prime and q is not and k = 2p - 2, ...
  • Langford sequences and a product of digraphs 

    López Masip, Susana Clara; Muntaner Batle, Francesc Antoni (2015-12-07)
    Article
    Restricted access - publisher's policy
    Skolem and Langford sequences and their many generalizations have applications in numerous areas. The ¿h-product is a generalization of the direct product of digraphs. In this paper we use the ¿h-product and super edge-magic ...
  • Conjugacy in houghton's groups 

    Antolin, Yago; Burillo Puig, José; Martino, Armando (2015)
    Article
    Open Access
    Let n ∈ N. Houghton’s group Hn is the group of permutations of {1, . . . , n} × N, that eventually act as a translation in each copy of N. We prove the solvability of the conjugacy problem and conjugator search problem for ...
  • The diameter of cyclic Kautz digraphs 

    Böhmová, Katerina; Dalfó Simó, Cristina; Huemer, Clemens (2015-11-12)
    Article
    Restricted access - publisher's policy
    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 ...

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