English

Toward \.Zak's conjecture on graph packing

Combinatorics 2015-08-18 v1

Abstract

Two graphs G1=(V1,E1)G_{1} = (V_{1}, E_{1}) and G2=(V2,E2)G_{2} = (V_{2}, E_{2}), each of order nn, pack if there exists a bijection ff from V1V_{1} onto V2V_{2} such that uvE1uv \in E_{1} implies f(u)f(v)E2f(u)f(v) \notin E_{2}. In 2014, \.{Z}ak proved that if Δ(G1),Δ(G2)n2\Delta (G_{1}), \Delta (G_{2}) \leq n-2 and E1+E2+max{Δ(G1),Δ(G2)}3n96n3/465|E_{1}| + |E_{2}| + \max \{ \Delta (G_{1}), \Delta (G_{2}) \} \leq 3n - 96n^{3/4} - 65, then G1G_{1} and G2G_{2} pack. In the same paper, he conjectured that if Δ(G1),Δ(G2)n2\Delta (G_{1}), \Delta (G_{2}) \leq n-2, then E1+E2+max{Δ(G1),Δ(G2)}3n7|E_{1}| + |E_{2}| + \max \{ \Delta (G_{1}), \Delta (G_{2}) \} \leq 3n - 7 is sufficient for G1G_{1} and G2G_{2} to pack. We prove that, up to an additive constant, \.{Z}ak's conjecture is correct. Namely, there is a constant CC such that if Δ(G1),Δ(G2)n2\Delta(G_1),\Delta(G_2) \leq n-2 and E1+E2+max{Δ(G1),Δ(G2)}3nC|E_{1}| + |E_{2}| + \max \{ \Delta(G_{1}), \Delta(G_{2}) \} \leq 3n - C, then G1G_{1} and G2G_{2} pack. In order to facilitate induction, we prove a stronger result on list packing.

Keywords

Cite

@article{arxiv.1508.03672,
  title  = {Toward \.Zak's conjecture on graph packing},
  author = {Ervin Győri and Alexandr Kostochka and Andrew McConvey and Derrek Yager},
  journal= {arXiv preprint arXiv:1508.03672},
  year   = {2015}
}

Comments

21 pages, 11 figures

R2 v1 2026-06-22T10:34:16.226Z