English

Maximum diameter of $3$- and $4$-colorable graphs

Combinatorics 2021-09-29 v1

Abstract

P. Erd\H{o}s, J. Pach, R. Pollack, and Z. Tuza [J. Combin. Theory, B 47 (1989), 279--285] made conjectures for the maximum diameter of connected graphs without a complete subgraph Kk+1K_{k+1}, which have order nn and minimum degree δ\delta. Settling a weaker version of a problem, by strengthening the Kk+1K_{k+1}-free condition to kk-colorable, we solve the problem for k=3k=3 and k=4k=4 using a unified linear programming duality approach. The case k=4k=4 is a substantial simplification of the result of \'E. Czabarka, P. Dankelmann, and L. A. Sz\'ekely [Europ. J. Comb., 30 (2009), 1082--1089].

Keywords

Cite

@article{arxiv.2109.13887,
  title  = {Maximum diameter of $3$- and $4$-colorable graphs},
  author = {Éva Czabarka and Stephen J. Smith and László Székely},
  journal= {arXiv preprint arXiv:2109.13887},
  year   = {2021}
}

Comments

8 pages. arXiv admin note: text overlap with arXiv:2009.02611

R2 v1 2026-06-24T06:27:02.359Z