Prohlížení dle autora "Volec J."

Zobrazují se záznamy 1-12 z 12

    • The codegree threshold of K_4- 

      Autor: Falgas-Ravry V.; Pikhurko O.; Vaughan E.; Volec J.
      (London Mathematical Society, 2023)
      The codegree threshold ex_2(n, F) of a 3-graph F is the minimum d = d(n) such that every 3-graph on n vertices in which every pair of vertices is contained in at least d + 1 edges contains a copy of F as a subgraph. We ...

    • Counterexamples to a Conjecture of Harris on Hall Ratio 

      Autor: Blumenthal A.; Lidický B.; Martin R.R.; Norin S.; Pfender F.; Volec J.
      (SIAM, 2022)
      In this work, we refute a conjecture of Harris by constructing various graphs whose fractional chromatic number grows much faster than their Hall ratio. The Hall ratio of a graph G is the maximum value of the ratio between ...

    • Cycles of a given length in tournaments 

      Autor: Grzesik A.; Král' D.; Lovász L.M.; Volec J.
      (Elsevier B.V., 2023)

    • Degree Conditions Forcing Directed Cycles 

      Autor: Grzesik A.; Volec J.
      (Oxford University Press, 2023)
      Caccetta-Haggkvist conjecture is a longstanding open problem on degree conditions that force an oriented graph to contain a directed cycle of a bounded length. Motivated by this conjecture, Kelly, Kuhn, and Osthus initiated ...

    • Large Multipartite Subgraphs in H-free Graphs 

      Autor: Hu P.; Lidický B.; Martins T.; Norin S.; Volec J.
      (Springer Nature Switzerland AG, 2021)
      In this work, we discuss a strengthening of a result of Füredi that every n-vertex K_{r+1}-free graph can be made r-partite by removing at most T(n, r) - e(G) edges, where T(n,r)=(r-1)/(2r) * n^2 denotes the number of edges ...

    • No additional tournaments are quasirandom-forcing 

      Autor: Hancock R.; Kabela A.; Kraľ D.; Martins T.; Parente R.; Skerman F.; Volec J.
      (Elsevier, 2023)
      A tournament H is quasirandom-forcing if the following holds for every sequence (G_n) is an element of N of tournaments of growing orders: if the density of H in G_n converges to the expected density of H in a random ...

    • Non-Bipartite K-Common Graphs 

      Autor: Kráľ D.; Noel J.A.; Norin S.; Volec J.; Wei F.
      (Akadémiai Kiadó, 2022)
      In this work, we construct the first examples of non-bipartite k-common graphs for k at least 3, which resolves a problem of Jagger, Stovícek and Thomason from 1996. A graph H is said to be "k-common" if the number of ...

    • On tripartite common graphs 

      Autor: Grzesik A.; Lee J.; Lidický B.; Volec J.
      (Cambridge University Press, 2022)
      This work provides several new classes of tripartite common graphs. A graph H is common if the number of monochromatic copies of H in a 2-edge-colouring of the complete graph K-n is asymptotically minimised by the random ...

    • Sharp bounds for decomposing graphs into edges and triangles 

      Autor: Blumenthal A.; Lidický B.; Pehova Y.; Pfender F.; Pikhurko O.; Volec J.
      (Cambridge University Press, 2021)
      In 1966, Erdos, Goodman and Posa proved that the edges of an n-vertex graph can be decomposed into at most n^2/4 cliques. Moreover, such a decomposition may consist of edges and triangles only. In 1980s, Gyori and Kostochka ...

    • THE SPECTRUM OF TRIANGLE-FREE GRAPHS 

      Autor: Balogh J.; Clemen F.; Lidický B.; Norin S.; Volec J.
      (SIAM, 2023)
      Denote by q_n(G) the smallest eigenvalue of the signless Laplacian matrix of an n vertex graph G. Brandt conjectured in 1997 that for regular triangle-free graphs q_n(G)<= 4n/25. We prove a stronger result: If G is a ...

    • A tight lower bound on the minimal dispersion 

      Autor: Trödler M.; Volec J.; Vybíral J.
      (Elsevier, 2024)

    • Toward characterizing locally common graphs 

      Autor: Hancock R.; Kráľ D.; Krnc M.; Volec J.
      (John Wiley & Sons, Ltd., 2023)
      A graph H is common if the number of monochromatic copies of H in a 2-edge-coloring of the complete graph is asymptotically minimized by the random coloring. The classification of common graphs is one of the most intriguing ...