English

Hom complexes of graphs of diameter $1$

Combinatorics 2019-05-16 v2

Abstract

Given a finite simplicial complex XX and a connected graph TT of diameter 11, in \cite{anton} Dochtermann had conjectured that Hom(T,G1,X)\text{Hom}(T,G_{1,X}) is homotopy equivalent to XX. Here, G1,XG_{1, X} is the reflexive graph obtained by taking the 11-skeleton of the first barycentric subdivision of XX and adding a loop at each vertex. This was proved by Dochtermann and Schultz in \cite{ds12}. In this article, we give an alternate proof of this result by understanding the structure of the cells of Hom(Kn,G1,X)(K_n,G_{1,X}), where KnK_n is the complete graph on nn vertices. We prove that the neighborhood complex of G1,XG_{1,X} is homotopy equivalent to XX and Hom(Kn,G1,X)(K_n,G_{1,X})\simeq Hom(Kn1,G1,X)(K_{n-1},G_{1,X}), for each n3n\geq 3.

Keywords

Cite

@article{arxiv.1807.10498,
  title  = {Hom complexes of graphs of diameter $1$},
  author = {Anurag Singh},
  journal= {arXiv preprint arXiv:1807.10498},
  year   = {2019}
}

Comments

11 pages, 2 figures