Now showing items 1-20 of 28

  • A mathematical model for dynamic memory networks 

    Fàbrega Canudas, José; Fiol Mora, Miquel Àngel; Serra Albó, Oriol; Andrés Yebra, José Luis (Iniciativa Digital Politècnica, 2011)
    Conference report
    Open Access
    The aim of this paper is to bring together the work done several years ago by M.A. Fiol and the other authors to formulate a quite general mathematical model for a kind of permutation networks known as dynamic memories. A ...
  • An algebraic model for the storage of data in parallel memories 

    Fiol Mora, Miquel Àngel; Serra Albó, Oriol (Springer, 1989)
    Part of book or chapter of book
    Open Access
    The 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 analogue of Vosper's theorem for extension fields 

    Bachoc, Christine; Serra Albó, Oriol; Zemor, Gilles (2017-11-01)
    Article
    Open Access
    We are interested in characterising pairs S, T of F-linear subspaces in a field extension L/F such that the linear span ST of the set of products of elements of S and of elements of T has small dimension. Our central result ...
  • Correlation among runners and some results on the lonely runner conjecture 

    Perarnau, Guillem; Serra Albó, Oriol (2016-10-03)
    Article
    Open Access
    The Lonely Runner Conjecture, posed independently by Wills and by Cusick, states that for any set of runners running along the unit circle with constant different speeds and starting at the same point, there is a time where ...
  • Counting configuration-free sets in groups 

    Rué Perna, Juan José; Serra Albó, Oriol; Vena Cros, Lluís (2017-01-01)
    Article
    Open Access
    © 2017 Elsevier Ltd. We provide asymptotic counting for the number of subsets of given size which are free of certain configurations in finite groups. Applications include sets without solutions to equations in non-abelian ...
  • Counting configuration–free sets in groups 

    Rué Perna, Juan José; Serra Albó, Oriol; Vena Cros, Lluís (2015)
    Conference lecture
    Restricted access - publisher's policy
    We present a unified framework to asymptotically count the number of sets, with a given cardinality, free of certain configurations. This is done by combining the hypergraph containers methodology joint with arithmetic ...
  • Cycle codes of graphs and MDS array codes 

    Serra Albó, Oriol; Zemor, Gilles (2009-07-30)
    Article
    Restricted access - publisher's policy
    We investigate how to colour edges of graph so that any two colours make up a spanning tree. This problem is equivalent to transforming the cycle code of a graph into a Maximum Distance Separable (MDS) array code. Adopting ...
  • General properties of c-circulant digraphs 

    Mora Giné, Mercè; Serra Albó, Oriol; Fiol Mora, Miquel Àngel (1988)
    Article
    Open Access
    A digraph is said to be a c-circulant if its adjacency matrix is c-circulant. This paper deals with general properties of this family of digraphs, as isomorphisms, regularity, strong connectivity, diameter and the relation ...
  • Memorial to Javier Cilleruelo: A Problem list 

    Candela, Pablo; Rué Perna, Juan José; Serra Albó, Oriol (2018-03-23)
    Article
    Open Access
    This is a list of problems in combinatorial number theory gathered on the occasion of the meeting The Music of Numbers to honor the memory of the late Javier Cilleruelo (1961-2016).
  • On a problem by Shapozenko on Johnson Graphs 

    Diego Gutiérrez, Victor; Serra Albó, Oriol (2018-09)
    Article
    Restricted access - publisher's policy
    The Johnson graph J(n, m) has the m-subsets of {1,2,…,n} as vertices and two subsets are adjacent in the graph if they share m-1 elements. Shapozenko asked about the isoperimetric function µn,m(k) of Johnson graphs, that ...
  • On doubling and volume: chains 

    Freiman, Gregory A.; Serra Albó, Oriol (\Institute of Mathematics, Polish Academy of Sciences\, 2018-10-01)
    Article
    Open Access
    The well-known Freiman–Ruzsa theorem provides a structural description of a set A of integers with |2A|=c|A| as a subset of a d–dimensional arithmetic progression P with |P|=c'|A|, where d and c' depend only on c. The ...
  • On monochromatic solutions of equations in groups 

    Cameron, Peter J.; Cilleruelo, Javier; Serra Albó, Oriol (2006-01-12)
    Article
    Open Access
    Resum no disponible
  • On some groups related to arc-colored digraphs 

    Serra Albó, Oriol; Fiol Mora, Miquel Àngel (Mediterranean press, 1988)
    Conference lecture
    Open Access
    An arc-coloring of a digraph G is an assignation of colors to its arcs in such a way that all arcs incident to each vertex, as well as all arcs incident from each vertex, have different colors. In an arc-colored d-regular ...
  • On sums of dilates 

    Javier, Cilleruelo; Hamidoune, Yahya ould; Serra Albó, Oriol (2009-10-05)
    Article
    Open Access
    For k prime and A a finite set of integers with |A| ≥ $3(k-1)^2$ (k-1)! we prove that |A+k·A| ≥ (k+1)|A| − ⌈k(k+2)/4⌉ where k·A = {ka:a∈A}. We also describe the sets for which equality holds.
  • On the number of monochromatic solutions of integer linear systems on Abelian groups 

    Serra Albó, Oriol; Vena, Lluis (2011-12-01)
    Article
    Restricted access - publisher's policy
    Let G be a finite cyclic group an let r be a positive integer. Let A be a k×m matrix with integer entries. We show that, if A satisfies some natural conditions, then the homogeneous linear system Ax=0 has Ω(|GN|m−k) ...
  • On the number of solutions of regular systems in sets with positive density in abelian groups 

    Král, Daniel; Serra Albó, Oriol; Vena, Lluis (2010)
    Conference report
    Restricted access - publisher's policy
    We prove a density version for the Ramsey statement that, for fixed r and sufficiently large n, every coloring of an abelian group of order n with r colors has nontrivial monochromatic solutions of the system Ax = 0, where ...
  • On the tree depth of random graphs 

    Perarnau Llobet, Guillem; Serra Albó, Oriol (2010)
    Conference report
    Restricted access - publisher's policy
    The tree-depth of a graph G is a parameter that plays a crucial role in the theory of bounded expansion classes and has been introduced under numerous names. We describe the asymptotic behaviour of this parameter in the ...
  • Perspectivas en combinatoria 

    Noy Serrano, Marcos; Serra Albó, Oriol (Real Sociedad Matemática Española, 2016-10-03)
    Article
    Open Access
  • Probabilitat i estadística 

    Burillo Puig, José; Miralles de la Asunción, Alicia; Serra Albó, Oriol (Edicions UPC, 2005)
    Book
    Restricted access to UB, UAB, UPC, UPF, UdG, UdL, URV, UOC, BC, UVic, UJI, URL, UIC users
    En aquest llibre s'ofereix una introducció a la probabilitat i a l'estadística adaptada a l'alumnat de primer curs d'una enginyeria tècnica, especialment les enginyeries relacionades amb les tecnologies de la informació. ...
  • Probabilitat i estadística 

    Burillo Puig, José; Miralles de la Asunción, Alicia; Serra Albó, Oriol (Edicions UPC, 2003)
    Book
    Restricted access to the UPC academic community
    En aquest llibre s'ofereix una introducció a la probabilitat i a l'estadística adaptada a l'alumnat de primer curs d'una enginyeria tècnica, especialment les enginyeries relacionades amb les tecnologies de la informació. ...