English

The existence of $\{p,q\}$-orientations in edge-connected graphs

Combinatorics 2022-05-19 v1

Abstract

In 1976 Frank and Gy{\'a}rf{\'a}s gave a necessary and sufficient condition for the existence of an orientation in an arbitrary graph GG such that for each vertex vv, the out-degree dG+(v)d^+_G(v) of it satisfies p(v)dG+(v)q(v)p(v)\le d^+_G(v)\le q(v), where pp and qq are two integer-valued functions on V(G)V(G) with pqp\le q. In this paper, we give a sufficient edge-connectivity condition for the existence of an orientation in GG such that for each vertex vv, dG+(v){p(v),q(v)}d^+_G(v)\in \{p(v),q(v)\}, provided that for each vertex vv, p(v)12dG(v)q(v)p(v)\le \frac{1}{2}d_G(v) \le q(v), q(v)p(v)k|q(v)-p(v)|\le k, and there is t(v){p(v),q(v)}t(v)\in \{p(v),q(v)\} in which E(G)=vV(G)t(v)|E(G)|=\sum_{v\in V(G)}t(v). This result is a generalization of a theorem due to Thomassen (2012) on the existence of modulo orientations in highly edge-connected graphs.

Keywords

Cite

@article{arxiv.2205.09038,
  title  = {The existence of $\{p,q\}$-orientations in edge-connected graphs},
  author = {Morteza Hasanvand},
  journal= {arXiv preprint arXiv:2205.09038},
  year   = {2022}
}

Comments

arXiv admin note: text overlap with arXiv:1702.07039