English

Oriented discrepancy of Hamilton cycles

Combinatorics 2023-03-13 v2

Abstract

We propose the following conjecture extending Dirac's theorem: if GG is a graph with n3n\ge 3 vertices and minimum degree δ(G)n/2\delta(G)\ge n/2, then in every orientation of GG there is a Hamilton cycle with at least δ(G)\delta(G) edges oriented in the same direction. We prove an approximate version of this conjecture, showing that minimum degree n/2+O(k)n/2 + O(k) guarantees a Hamilton cycle with at least (n+k)/2(n+k)/2 edges oriented in the same direction. We also study the analogous problem for random graphs, showing that if the edge probability p=p(n)p = p(n) is above the Hamiltonicity threshold, then, with high probability, in every orientation of GG(n,p)G \sim G(n,p) there is a Hamilton cycle with (1o(1))n(1-o(1))n edges oriented in the same direction.

Keywords

Cite

@article{arxiv.2203.07148,
  title  = {Oriented discrepancy of Hamilton cycles},
  author = {Lior Gishboliner and Michael Krivelevich and Peleg Michaeli},
  journal= {arXiv preprint arXiv:2203.07148},
  year   = {2023}
}
R2 v1 2026-06-24T10:12:28.035Z