English

Simplicial complexes and matroids with vanishing $T^2$

Combinatorics 2025-03-21 v2 Commutative Algebra Algebraic Geometry

Abstract

We investigate quotients by radical monomial ideals for which T2T^2, the second cotangent cohomology module, vanishes. The dimension of the graded components of T2T^2, and thus their vanishing, depends only on the combinatorics of the corresponding simplicial complex. We give both a complete characterization and a full list of one dimensional complexes with T2=0T^2=0. We characterize the graded components of T2T^2 when the simplicial complex is a uniform matroid. Finally, we show that T2T^2 vanishes for all matroids of corank at most two and conjecture that all connected matroids with vanishing T2T^2 are of corank at most two.

Keywords

Cite

@article{arxiv.2406.02440,
  title  = {Simplicial complexes and matroids with vanishing $T^2$},
  author = {Alexandru Constantinescu and Patricia Klein and Thai Thanh Nguyen and Anurag Singh and Lorenzo Venturello},
  journal= {arXiv preprint arXiv:2406.02440},
  year   = {2025}
}

Comments

To appear in the Electronic Journal of Combinatorics

R2 v1 2026-06-28T16:53:09.492Z