Enviaments recents

  • Abelian Cayley digraphs with asymptotically large order for any given degree 

    Aguiló Gost, Francisco de Asis L.; Fiol Mora, Miquel Àngel; Pérez Mansilla, Sonia (2016-04-29)
    Article
    Accés obert
    Abelian Cayley digraphs can be constructed by using a generalization to Z(n) of the concept of congruence in Z. Here we use this approach to present a family of such digraphs, which, for every fixed value of the degree, ...
  • Sequence mixed graphs 

    Dalfó Simó, Cristina; Fiol Mora, Miquel Àngel; López, Nacho (2016-12)
    Article
    Accés obert
    A mixed graph can be seen as a type of digraph containing some edges (or two opposite arcs). Here we introduce the concept of sequence mixed graphs, which is a generalization of both sequence graphs and literated line ...
  • Algorithmic recognition of infinite cyclic extensions 

    Cavallo, Bren; Delgado Rodríguez, Jordi; Kahrobaei, Delaram; Ventura Capell, Enric (2016-10-25)
    Article
    Accés restringit per política de l'editorial
    We prove that one cannot algorithmically decide whether a finitely presented Z-extension admits a finitely generated base group, and we use this fact to prove the undecidability of the BNS invariant. Furthermore, we show ...
  • Distance mean-regular graphs 

    Fiol Mora, Miquel Àngel; Diego, Victor (2016)
    Article
    Accés restringit per política de l'editorial
    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 ...
  • José Gómez Martí 1968-2014: in memoriam 

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

    Dalfó Simó, Cristina; Fiol Mora, Miquel Àngel (Wiley, 2016-07-27)
    Article
    Accés restringit per política de l'editorial
    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
    Accés restringit per política de l'editorial
    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
    Accés restringit per política de l'editorial
    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
    Accés obert
    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
    Accés obert
    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 ...

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