English

The complexity of matroid homomorphism reconfiguration

Combinatorics 2025-03-26 v1

Abstract

We consider a reconfiguration version of the homomorphism problem HomM(N){\rm Hom}_\mathbb{M}(N) for binary matroids NN. This reconfiguration problem, RecolM(N){\rm Recol}_\mathbb{M}(N), asks, for two homomorphisms ϕ\phi and ψ\psi of a matroid MM to NN, if there is a path of homomorphism from ϕ\phi to ψ\psi such that consecutive homomorphism in the path differ on a single cocircuit of NN. We show that this problem is trivial in the case that NN dismantles to the graphic matroid M(K2)M(K_2), and that the problem is PSPACE{\rm PSPACE}-complete when NN is the graphic matroid M(K3)M(K_3), M(K4)M(K_4), or any graphic matroid containing M(K5)M(K_5).

Keywords

Cite

@article{arxiv.2503.19181,
  title  = {The complexity of matroid homomorphism reconfiguration},
  author = {Cheolwon Heo and Mark Siggers},
  journal= {arXiv preprint arXiv:2503.19181},
  year   = {2025}
}