English

The (1,2)-step competition graph of a hypertournament

Combinatorics 2018-12-06 v1

Abstract

Competition graphs were created in connected to a biological model as a means of reflecting the competition relations among the predators in the food webs and determining the smallest dimension of ecological phase space. In 2011, Factor and Merz introduced the (1,2)-step competition graph of a digraph. Given a digraph D=(V,A)D=(V,A), the (1,2)-step competition graph of DD, denoted C1,2(D)C_{1,2}(D), is a graph on V(D)V(D) where xyE(C1,2(D))xy\in E(C_{1,2}(D)) if and only if there exists a vertex zx,yz\neq x,y such that either dDy(x,z)=1d_{D-y}(x,z)=1 and dDx(y,z)2d_{D-x}(y,z)\leq 2 or dDx(y,z)=1d_{D-x}(y,z)=1 and dDy(x,z)2d_{D-y}(x,z)\leq 2. They also characterized the (1,2)-step competition graphs of tournaments and extended some results to the (i,j)(i,j)-step competition graphs of tournaments. In this paper, the definition of the (1,2)-step competition graph of a digraph is generalized to the one of a hypertournament and the (1,2)(1,2)-step competition graph of a kk-hypertournament is characterized. Also, the results are extended to the (i,j)(i,j)-step competition graph of a kk-hypertournament.

Keywords

Cite

@article{arxiv.1812.01796,
  title  = {The (1,2)-step competition graph of a hypertournament},
  author = {Ruijuan Li and Xiaoting An and Xinhong Zhang},
  journal= {arXiv preprint arXiv:1812.01796},
  year   = {2018}
}