$f$-vectors of balanced simplicial complexes, flag spheres, and geometric Lefschetz decompositions

Fuente: arXiv
Saved in:
Bibliographic Details
Main Author: Park, Soohyun
Format: Preprint
Published: 2024
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866913541637799936
author Park, Soohyun
author_facet Park, Soohyun
contents We show that there are $f$-vectors of balanced simplicial complexes giving a source of simplicial complexes exhibiting a Boolean decomposition similar to a geometric Lefschetz decomposition. The objects we are working with are $h$-vectors of flag spheres and balanced simplicial complexes whose $f$-vectors are equal to them. This builds on work of Nevo--Petersen--Tenner on a conjecture of Nevo--Petersen that the gamma vector of an odd-dimensional flag sphere is the $f$-vector of a balanced simplicial complex (which was shown for barycentric subdivisions by Nevo--Petersen--Tenner). We can connect our decomposition to positivity questions on reciprocal/palindromic polynomials associated to flag spheres and geometric questions motivating them. In addition, we note that the degrees in the Lefschetz-like decomposition are not halved unlike the usual $h$-vector setting.
format Preprint
id arxiv_https___arxiv_org_abs_2410_08139
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle $f$-vectors of balanced simplicial complexes, flag spheres, and geometric Lefschetz decompositions
Park, Soohyun
Combinatorics
Algebraic Geometry
Geometric Topology
We show that there are $f$-vectors of balanced simplicial complexes giving a source of simplicial complexes exhibiting a Boolean decomposition similar to a geometric Lefschetz decomposition. The objects we are working with are $h$-vectors of flag spheres and balanced simplicial complexes whose $f$-vectors are equal to them. This builds on work of Nevo--Petersen--Tenner on a conjecture of Nevo--Petersen that the gamma vector of an odd-dimensional flag sphere is the $f$-vector of a balanced simplicial complex (which was shown for barycentric subdivisions by Nevo--Petersen--Tenner). We can connect our decomposition to positivity questions on reciprocal/palindromic polynomials associated to flag spheres and geometric questions motivating them. In addition, we note that the degrees in the Lefschetz-like decomposition are not halved unlike the usual $h$-vector setting.
title $f$-vectors of balanced simplicial complexes, flag spheres, and geometric Lefschetz decompositions
topic Combinatorics
Algebraic Geometry
Geometric Topology
url https://arxiv.org/abs/2410.08139