English

Singular Tur\'an numbers and WORM-colorings

Combinatorics 2019-09-12 v1

Abstract

A subgraph HH of GG is \textit{singular} if the vertices of HH either have the same degree in GG or have pairwise distinct degrees in GG. The largest number of edges of a graph on nn vertices that does not contain a singular copy of HH is denoted by TS(n,H)T_S(n,H). Caro and Tuza [Theory and Applications of Graphs, 6 (2019), 1--32] obtained the asymptotics of TS(n,H)T_S(n,H) for every graph HH, but determined the exact value of this function only in the case H=K3H=K_3 and n2n\equiv 2 (mod 4). We determine TS(n,K3)T_S(n,K_3) for all n0n\equiv 0 (mod 4) and n1n\equiv 1 (mod 4), and also TS(n,Kr+1)T_S(n,K_{r+1}) for large enough nn that is divisible by rr. We also explore the connection to the so-called HH-WORM colorings (colorings without rainbow or monochromatic copies of HH) and obtain new results regarding the largest number of edges that a graph with an HH-WORM coloring can have.

Keywords

Cite

@article{arxiv.1909.04980,
  title  = {Singular Tur\'an numbers and WORM-colorings},
  author = {Dániel Gerbner and Balázs Patkós and Zsolt Tuza and Máté Vizer},
  journal= {arXiv preprint arXiv:1909.04980},
  year   = {2019}
}