Exploració per autor "Vena Cros, Lluís"
Ara es mostren els items 1-11 de 11
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A removal lemma for systems of linear equations over finite fields
Král, Daniel; Serra Albó, Oriol; Vena Cros, Lluís (2012-01)
Article
Accés obertWe 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 = ... -
Big Ramsey degrees of 3-uniform hypergraphs
Balko, Martin; Chodounsky, David; Hubicka, Jan; Konecny, Matej; Vena Cros, Lluís (2019)
Text en actes de congrés
Accés obertGiven a countably infinite hypergraph $\mathcal R$ and a finite hypergraph $\mathcal A$, the \emph{big Ramsey degree} of $\mathcal A$ in $\mathcal R$ isthe least number $L$ such that, for every finite $k$ and every ... -
Caracteritzant els codis de Gauss: només cal girar la cantonada
Vena Cros, Lluís (2020-02-05)
Article
Accés obertAquest document està dedicat a la història, les motivacions i algunes solu-cions alproblema dels codis de Gauss.Una corba tancada al pla pot contenir punts d’autointersecció; en suposem unnombre finit, suposem els talls ... -
Counting configuration-free sets in groups
Rué Perna, Juan José; Serra Albó, Oriol; Vena Cros, Lluís (2017-01-01)
Article
Accés obert© 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)
Comunicació de congrés
Accés restringit per política de l'editorialWe 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 ... -
Extremal families for Kruskal-Katona Theorem
Serra Albó, Oriol; Vena Cros, Lluís (2019)
Text en actes de congrés
Accés obertGiven a set of size $n$ and a positive integer $k<n$, Kruskal--Katona theorem gives the minimum size of the shadow of a family $S$ of $k$-sets of $[n]$ in terms of the cardinality of $S$. We give a characterization of the ... -
Homomorphisms between graphs embedded in surfaces
Garijo Royo, Delia; Goodall, Andrew; Vena Cros, Lluís (Elsevier, 2024-05)
Article
Accés obertWe extend the notion of graph homomorphism to cellularly embedded graphs (maps) by designing operations on vertices and edges that respect the surface topology; we thus obtain the first definition of map homomorphism that ... -
Irreducibility of the Tutte polynomial of an embedded graph
Ellis Monaghan, Joanna A.; Goodall, Andrew; Moffatt, Iain; Noble, Steven D.; Vena Cros, Lluís (2022-12-19)
Article
Accés obertWe prove that the ribbon graph polynomial of a graph embedded in an orientable surface is irreducible if and only if the embedded graph is neither the disjoint union nor the join of embedded graphs. This result is analogous ... -
The canonical Tutte polynomial for signed graphs
Goodall, Andrew; Litjens, Bart; Regts, Guus; Vena Cros, Lluís (2019)
Text en actes de congrés
Accés obertWe construct a new polynomial invariant for signed graphs, the trivariate Tutte polynomial, which contains among its evaluations the number of proper colorings and the number of nowhere-zero flows. In this, it parallels ... -
The regularity Lemma in additive combinatorics
Vena Cros, Lluís (Universitat Politècnica de Catalunya, 2007)
Projecte Final de Màster Oficial
Accés obertThe Szemerédi Regularity Lemma (SzRL) was introduced by Endré Szemerédi in his celebrated proof of the density version of Van der Waerden Theorem, namely, that a set of integers with positive density contains arbitrarily ... -
The Removal Lemma: algebraic versions and applications
Vena Cros, Lluís (Universitat Politècnica de Catalunya, 2012-07-02)
Tesi
Accés obertThis thesis presents some contributions in additive combinatorics and arithmetic Ramsey theory. More specifically, it deals with the interaction between combinatorics, number theory and additive combinatorics. This area ...