A simple proof for folds on both sides in complexes of graph homomorphisms
| dc.creator | Kozlov, Dmitry N. | |
| dc.date | 2004-08-19 | |
| dc.date | 2004-12-03 | |
| dc.date.accessioned | 2026-07-07T06:27:38Z | |
| dc.date.available | 2026-07-07T06:27:38Z | |
| dc.description | In this paper we study implications of folds in both parameters of Lovász' Hom(-,-) complexes. There is an important connection between the topological properties of these complexes and lower bounds for chromatic numbers. We give a very short and conceptual proof of the fact that if G-v is a fold of G, then Bd(Hom(G,H)) collapses onto Bd Hom(G-v,H), whereas Hom(H,G) collapses onto Hom(H,G-v). We also give an easy inductive proof of the only nonelementary fact which we use for our arguments: if $ϕ$ is a closure operator on P, then $Δ(P)$ collapses onto $Δ(ϕ(P))$. | |
| dc.description | Final version, to appear in Proceedings of the American Mathematical Society | |
| dc.identifier | https://arxiv.org/abs/math/0408262 | |
| dc.identifier | http://arxiv.org/abs/math/0408262 | |
| dc.identifier | Proc. Amer. Math. Soc. 134 (2006), no. 5, 1265--1270 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/97469 | |
| dc.subject | Combinatorics | |
| dc.subject | Algebraic Topology | |
| dc.subject | 05C15; 57M15 | |
| dc.title | A simple proof for folds on both sides in complexes of graph homomorphisms | |
| dc.type | text |