English

Avoiding and extending partial edge colorings of hypercubes

Combinatorics 2021-04-05 v1

Abstract

We consider the problem of extending and avoiding partial edge colorings of hypercubes; that is, given a partial edge coloring φ\varphi of the dd-dimensional hypercube QdQ_d, we are interested in whether there is a proper dd-edge coloring of QdQ_d that agrees with the coloring φ\varphi on every edge that is colored under φ\varphi; or, similarly, if there is a proper dd-edge coloring that disagrees with φ\varphi on every edge that is colored under φ\varphi. In particular, we prove that for any d1d\geq 1, if φ\varphi is a partial dd-edge coloring of QdQ_d, then φ\varphi is avoidable if every color appears on at most d/8d/8 edges and the coloring satisfies a relatively mild structural condition, or φ\varphi is proper and every color appears on at most d2d-2 edges. We also show that the same conclusion holds if dd is divisible by 33 and every color class of φ\varphi is an induced matching. Moreover, for all 1kd1 \leq k \leq d, we characterize for which configurations consisting of a partial coloring φ\varphi of dkd-k edges and a partial coloring ψ\psi of kk edges, there is an extension of φ\varphi that avoids ψ\psi.

Keywords

Cite

@article{arxiv.2104.00716,
  title  = {Avoiding and extending partial edge colorings of hypercubes},
  author = {Carl Johan Casselgren and Per Johansson and Klas Markström},
  journal= {arXiv preprint arXiv:2104.00716},
  year   = {2021}
}
R2 v1 2026-06-24T00:47:16.148Z