Ara es mostren els items 14-33 de 41

    • Existence of spanning F-free subgraphs with large minimum degree 

      Perarnau Llobet, Guillem; Reed, Bruce (2016-12-07)
      Article
      Accés restringit per política de l'editorial
      Let F be a family of graphs and let d be large enough. For every d-regular graph G, we study the existence of a spanning F-free subgraph of G with large minimum degree. This problem is well understood if F does not contain ...
    • Fast recoloring of sparse graphs 

      Bousquet, Nicolas; Perarnau Llobet, Guillem (2015-09-07)
      Article
      Accés obert
      In this paper, we show that for every graph of maximum average degree bounded away from d and any two (d + 1)-colorings of it, one can transform one coloring into the other one within a polynomial number of vertex recolorings ...
    • Frozen (¿ + 1)-colourings of bounded degree graphs 

      Bonamy, Marthe; Bousquet, Nicolas; Perarnau Llobet, Guillem (2020-10-19)
      Article
      Accés restringit per política de l'editorial
      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 ...
    • How to determine if a random graph with a fixed degree sequence has a giant component 

      Joos, Felix; Perarnau Llobet, Guillem; Rautenbach, Dieter; Reed, Bruce (2017-01-26)
      Article
      Accés obert
      For a fixed degree sequence D=(d1,…,dn) , let G(D) be a uniformly chosen (simple) graph on {1,…,n} where the vertex i has degree di . In this paper we determine whether G(D) has a giant component with high probability, ...
    • How to determine if a random graph with a fixed degree sequence has a giant component 

      Joos, Felix; Perarnau Llobet, Guillem; Rautenbach, Dieter; Reed, Bruce (Institute of Electrical and Electronics Engineers (IEEE), 2016)
      Text en actes de congrés
      Accés obert
      The traditional Erdos-Renyi model of a random network is of little use in modelling the type of complex networks which modern researchers study. In this graph, every pair of vertices is equally likely to be connected by ...
    • Improved bounds for randomly sampling colorings via linear programming 

      Chen, Sitan; Delcourt, Michelle; Moitra, Ankur; Perarnau Llobet, Guillem; Postle, Luke (2019)
      Text en actes de congrés
      Accés restringit per política de l'editorial
      A well-known conjecture in computer science and statistical physics is that Glauber dynamics on the set of k-colorings of a graph G on n vertices with maximum degree ¿ is rapidly mixing for k = ¿ + 2. In FOCS 1999, Vigoda ...
    • Large subgraphs without short cycles 

      Foucaud, Florent; Krivelevich, Michael; Perarnau Llobet, Guillem (2015-01-06)
      Article
      Accés obert
      We study two extremal problems about subgraphs excluding a family F of graphs. i) Among all graphs with m edges, what is the smallest size f(m, F) of a largest F–free subgraph? ii) Among all graphs with minimum degree d ...
    • Local convergence and stability of tight bridge-addable classes 

      Chapuy, G.; Perarnau Llobet, Guillem (Canadian Mathematical Society, 2020-06-01)
      Article
      Accés restringit per política de l'editorial
      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, ...
    • Matchings in random biregular bipartite graphs 

      Perarnau Llobet, Guillem; Petridis, Georgios (2013-03-24)
      Article
      Accés obert
      We study the existence of perfect matchings in suitably chosen induced subgraphs of random biregular bipartite graphs. We prove a result similar to a classical theorem of Erdös and Rényi about perfect matchings in random ...
    • On the number of coloured triangulations of d-manifolds 

      Chapuy, G.; Perarnau Llobet, Guillem (2020-03-11)
      Article
      Accés obert
      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 the relation between graph distance and Euclidean distance in random geometric graphs 

      Díaz Cort, Josep; Dieter Wilhelm, Mitsche; Perarnau Llobet, Guillem; Pérez Giménez, Xavier (2016-09-01)
      Article
      Accés obert
      Given any two vertices u, v of a random geometric graph G(n, r), denote by dE(u, v) their Euclidean distance and by dE(u, v) their graph distance. The problem of finding upper bounds on dG(u, v) conditional on dE(u, v) ...
    • On the tree depth of random graphs 

      Perarnau Llobet, Guillem; Serra Albó, Oriol (2010)
      Text en actes de congrés
      Accés restringit per política de l'editorial
      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 ...
    • On the treewidth and related parameters of random geometric graphs 

      Mitsche, Dieter; Perarnau Llobet, Guillem (2017-06-22)
      Article
      Accés restringit per política de l'editorial
      We give asymptotically exact values for the treewidth tw(G) of a random geometric graph G ¿ G(n, r) in [0, v n] 2 . More precisely, let rc denote the threshold radius for the appearance of the giant component in G(n, r). ...
    • Overlapping community search for social networks 

      Padrol Sureda, Arnau; Perarnau Llobet, Guillem; Pfeifle, Julián; Muntés Mulero, Víctor (IEEE Press. Institute of Electrical and Electronics Engineers, 2010)
      Text en actes de congrés
      Accés obert
      Finding decompositions of a graph into a family of clusters is crucial to understanding its underlying structure. While most existing approaches focus on partitioning the nodes, real-world datasets suggest the presence ...
    • Percolation on random graphs with a fixed degree sequence 

      Fountoulakis, Nikolaos; Joos, Felix; Perarnau Llobet, Guillem (2022-01-04)
      Article
      Accés obert
      We consider bond percolation on random graphs with given degrees and bounded average degree. In particular, we consider the order of the largest component after the random deletion of the edges of such a random graph. We ...
    • Probabilistic methods and coloring problems in graphs 

      Perarnau Llobet, Guillem (Universitat Politècnica de Catalunya, 2010-06)
      Projecte Final de Màster Oficial
      Accés obert
      Aquest projecte està dedicat a estudiar el k-èssim nombre cromàtic generalitzat que sorgeix de les descomposicions Low Tree--Depth en grafs usant mètodes probabilístics.. Una extensió natural del nombre cromàtic d'un graf ...
    • Rainbow factors in hypergraphs 

      Coulson, Matthew John; Keevash, Peter; Perarnau Llobet, Guillem; Yepremyan, Liana (2020-05-01)
      Article
      Accés obert
      For any r-graph H, we consider the problem of finding a rainbow H-factor in an r-graph G with large minimum l-degree and an edge-colouring that is suitably bounded. We show that the asymptotic degree threshold is the same ...
    • Rainbow matchings in Dirac bipartite graphs 

      Coulson, Matthew John; Perarnau Llobet, Guillem (2019-01-15)
      Article
      Accés obert
      We show the existence of rainbow perfect matchings in µn-bounded edge colorings of Dirac bipartite graphs, for a sufficiently small µ¿>¿0. As an application of our results, we obtain several results on the existence of ...
    • Rainbow perfect matchings in r-partite graph structures 

      Cano Vila, María del Pilar; Perarnau Llobet, Guillem; Serra Albó, Oriol (2016-10-03)
      Article
      Accés obert
      A matching M in an edge–colored (hyper)graph is rainbow if each pair of edges in M have distinct colors. We extend the result of Erdos and Spencer on the existence of rainbow perfect matchings in the complete bipartite ...
    • Rainbow spanning subgraphs in bounded edge–colourings of graphs with large minimum degree 

      Cano Vila, María del Pilar; Perarnau Llobet, Guillem; Serra Albó, Oriol (2017-08-01)
      Article
      Accés obert
      We study the existence of rainbow perfect matching and rainbow Hamiltonian cycles in edge–colored graphs where every color appears a bounded number of times. We derive asymptotically tight bounds on the minimum degree of ...