Strict Erd\H{o}s-Ko-Rado theorems for simplicial complexes
Combinatorics
2025-07-02 v2
Abstract
We show that if a simplicial complex is a near-cone of sufficiently high depth, then the only maximum families of small pairwise intersecting faces are those with a common intersection. Thus, near-cones of sufficiently high depth satisfy the strict Erd\H{o}s-Ko-Rado property conjectured by Holroyd and Talbot and by Borg. One consequence is a strict Erd\H{o}s-Ko-Rado theorem for independence complexes of chordal graphs with an isolated vertex. Under stronger shiftedness conditions, we prove a sharper stability theorem of Hilton-Milner type, as well as two cross-intersecting theorems.
Cite
@article{arxiv.2503.15608,
title = {Strict Erd\H{o}s-Ko-Rado theorems for simplicial complexes},
author = {Denys Bulavka and Russ Woodroofe},
journal= {arXiv preprint arXiv:2503.15608},
year = {2025}
}
Comments
18 pages. v2 has a minor correction