Betti numbers of skeletons of thick trees

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Authors: Ralf Fröberg
Cited by: 0

Abstract

The starting point is the class of the following simplicial complexes $Δ$ with 2-linear resolutions. The facets of $Δ$ are $F_1,\ldots,F_n$, and we demand that for each $i$ $F_i\cap (F_1\cup \cdots\cup F_{i-1}\cup F_{i+1}\cdots\cup F_n)$ be a point. We will determine the Betti numbers, and thus the projective dimension, the depth, and the regularity of the Stanley-Reisner rings of all skeletons of such complexes. It follows that we know when these complexes are Cohen-Macaulay. Also, there are two ways to determine the Hilbert series of $Δ$, giving sequences of identities for binomial coefficients.

Fields of Study & Subjects

Commutative Algebra and Its Applications Advanced Combinatorial Mathematics Polynomial and algebraic computation

Publication details

Journal / source
arXiv (Cornell University)
Publication date
25 February 2026
Language
EN
Document type
Preprint