Recent Submissions

  • On strong infinite Sidon and Bh sets and random sets of integers 

    Fabian, David; Rué Perna, Juan José; Spiegel, Christoph (2021-04-21)
    Article
    Restricted access - publisher's policy
    A set of integers S ¿ N is an a–strong Sidon set if the pairwise sums of its elements are far apart by a certain measure depending on a, more specifically if (x + w) - (y + z) = max{xa, ya, za, wa} for every x, y, z, ...
  • Degrees of compression and inertia for free-abelian times free groups 

    Roy, Mallika; Ventura Capell, Enric (Elsevier, 2021-02-15)
    Article
    Restricted access - publisher's policy
    We introduce the concepts of degree of inertia, diG(H), and degree of compression,dcG(H), of a finitely generated subgroupHof a given groupG. For the case of direct productsof free-abelian and free groups, we compute the ...
  • A removal lemma for systems of linear equations over finite fields 

    Král, Daniel; Serra Albó, Oriol; Vena Cros, Lluís (2012-01)
    Article
    Open Access
    We prove a removal lemma for systems of linear equations over finite fields: let X1, . . . , Xm be subsets of the finite field Fq and let A be a (k × m) matrix with coefficients in Fq and rank k; if the linear system Ax = ...
  • Triangulations and a discrete Brunn–Minkowski inequality in the plane 

    Böröczky, Károly J.; Matolcsi, Máté; Ruzsa, Imre Z.; Santos Leal, Francisco; Serra Albó, Oriol (2019-08-29)
    Article
    Open Access
    For a set A of points in the plane, not all collinear, we denote by tr(A) the number of triangles in a triangulation of A, that is, tr(A)=2i+b-2 , where b and i are the numbers of boundary and interior points of the convex ...
  • Product of primes in arithmetic progressions 

    Ramaré, Olivier; Srivastav, Priyamvad; Serra Albó, Oriol (2020-05-01)
    Article
    Open Access
    We prove that, for all q=2 and for all invertible residue classes a modulo q, there exists a natural number n=(650q)9 that is congruent to a modulo q and that is the product of exactly three primes, all of which are below ...
  • Frozen (¿ + 1)-colourings of bounded degree graphs 

    Bonamy, Marthe; Bousquet, Nicolas; Perarnau Llobet, Guillem (2020-10-19)
    Article
    Restricted access - publisher's policy
    Let G be a graph on n vertices and with maximum degree ¿, and let k be an integer. The k-recolouring graph of G is the graph whose vertices are k-colourings of G and where two k-colourings are adjacent if they differ at ...
  • On a problem of Sárközy and Sós for multivariate linear forms 

    Rué Perna, Juan José; Spiegel, Christoph (2020-03-18)
    Article
    Open Access
    We prove that for pairwise co-prime numbers k1,…,kd=2 there does not exist any infinite set of positive integers A such that the representation function rA(n)=# {(a1,…,ad)¿Ad:k1a1+¿ +kdad=n} becomes constant for n large ...
  • An Erdös–Fuchs theorem for ordered representation functions 

    Cao Labora, Gonzalo; Rué Perna, Juan José; Spiegel, Christoph (2020-10-28)
    Article
    Open Access
    Letk=2 be a positive integer. We study concentration results for the ordered representationfunctionsr=k(A, n) = #{(a1= ··· =ak)¿ Ak:a1+···+ak=n}andr<k(A, n) = #{(a1<···<ak)¿ Ak:a1+···+ak=n}for any infinite set ...
  • Local convergence and stability of tight bridge-addable classes 

    Chapuy, G.; Perarnau Llobet, Guillem (Canadian Mathematical Society, 2020-06-01)
    Article
    Restricted access - publisher's policy
    A class of graphs is bridge-addable if given a graph G in the class, any graph obtained by adding an edge between two connected components of G is also in the class. The authors recently proved a conjecture of McDiarmid, ...
  • Structure and enumeration of K4-minor-free links and link-diagrams 

    Rué Perna, Juan José; Thilikos Touloupas, Dimitrios; Velona, Vasiliki (2020-10-01)
    Article
    Open Access
    We study the class of link-types that admit a -minor-free diagram, i.e., they can be projected on the plane so that the resulting graph does not contain any subdivision of . We prove that is the closure of a subclass of ...
  • On the number of coloured triangulations of d-manifolds 

    Chapuy, G.; Perarnau Llobet, Guillem (2020-03-11)
    Article
    Open Access
    We give superexponential lower and upper bounds on the number of coloured d-dimensional triangulations whose underlying space is an oriented manifold, when the number of simplices goes to infinity and d=3 is fixed. In the ...
  • On varieties defined by large sets of quadrics and their application to error-correcting codes 

    Ball, Simeon Michael; Pepe, Valentina (2020-10-01)
    Article
    Restricted access - publisher's policy
    Let U be a ( k-1 2 - 1)-dimensional subspace of quadratic forms defined on F k with the property that U does not contain any reducible quadratic form. Let V (U) be the points of PG(k - 1, F) which are zeros of all quadratic ...

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