English

Hamiltonian cycles and paths in hypercubes with disjoint faulty edges

Discrete Mathematics 2021-06-28 v2 Combinatorics

Abstract

We consider hypercubes with pairwise disjoint faulty edges. An nn-dimensional hypercube QnQ_n is an undirected graph with 2n2^n nodes, each labeled with a distinct binary strings of length nn. The parity of the vertex is 0 if the number of ones in its labels is even, and is 1 if the number of ones is odd. Two vertices aa and bb are connected by the edge iff aa and bb differ in one position. If aa and bb differ in position ii, then we say that the edge (a,b)(a,b) goes in direction ii and we define the parity of the edge as the parity of the end with 0 on the position ii. It was already known that QnQ_n is not Hamiltonian if all edges going in one direction and of the same parity are faulty. In this paper we show that if n4n\ge4 then all other hypercubes are Hamiltonian. In other words, every cube QnQ_n, with n4n\ge4 and disjoint faulty edges is Hamiltonian if and only if for each direction there are two healthy crossing edges of different parity.

Keywords

Cite

@article{arxiv.1811.11516,
  title  = {Hamiltonian cycles and paths in hypercubes with disjoint faulty edges},
  author = {Janusz Dybizbański and Andrzej Szepietowski},
  journal= {arXiv preprint arXiv:1811.11516},
  year   = {2021}
}