Lorentzian polynomials

P Brändén, J Huh - Annals of Mathematics, 2020 - projecteuclid.org
We study the class of Lorentzian polynomials. The class contains homogeneous stable
polynomials as well as volume polynomials of convex bodies and projective varieties. We …

Valuative invariants for large classes of matroids

L Ferroni, B Schröter - Journal of the London Mathematical …, 2024 - Wiley Online Library
We study an operation in matroid theory that allows one to transition a given matroid into
another with more bases via relaxing a stressed subset. This framework provides a new …

[HTML][HTML] Hilbert–Poincaré series of matroid Chow rings and intersection cohomology

L Ferroni, JP Matherne, M Stevens, L Vecchi - Advances in Mathematics, 2024 - Elsevier
We study the Hilbert series of four objects arising in the Chow-theoretic and Kazhdan–
Lusztig framework of matroids. These are, respectively, the Hilbert series of the Chow ring …

[PDF][PDF] Equality cases of the Alexandrov–Fenchel inequality are not in the polynomial hierarchy

SH Chan, I Pak - Proceedings of the 56th Annual ACM Symposium on …, 2024 - dl.acm.org
Describing the equality conditions of the Alexandrov–Fenchel inequality has been a major
open problem for decades. We prove that for a natural class of convex polytopes, the …

Simplicial generation of Chow rings of matroids

S Backman, C Eur, C Simpson - Journal of the European Mathematical …, 2023 - ems.press
We introduce a presentation of the Chow ring of a matroid by a new set of generators, called
“simplicial generators.” These generators are analogous to nef divisors on projective toric …

The Fox trapezoidal conjecture for alternating knots

N Chbili - Symmetry, 2024 - mdpi.com
A long-standing conjecture due to R. Fox states that the coefficients of the Alexander
polynomial of an alternating knot exhibit a trapezoidal pattern. In other words, these …

What is in# P and what is not?

C Ikenmeyer, I Pak - 2022 IEEE 63rd Annual Symposium on …, 2022 - ieeexplore.ieee.org
For several classical nonnegative integer functions we investigate if they are members of the
counting complexity class# P or not. We prove# P membership in surprising cases, and in …

The geometry of geometries: matroid theory, old and new

F Ardila-Mantilla - Proc. Int. Cong. Math, 2022 - ems.press
The theory of matroids or combinatorial geometries originated in linear algebra and graph
theory, and has deep connections with many other areas, including field theory, matching …

The extremals of the Alexandrov-Fenchel inequality for convex polytopes

Y Shenfeld, R van Handel - arxiv preprint arxiv:2011.04059, 2020 - arxiv.org
The Alexandrov-Fenchel inequality, a far-reaching generalization of the classical
isoperimetric inequality to arbitrary mixed volumes, lies at the heart of convex geometry. The …

Log-concave poset inequalities

SH Chan, I Pak - arxiv preprint arxiv:2110.10740, 2021 - arxiv.org
We study combinatorial inequalities for various classes of set systems: matroids,
polymatroids, poset antimatroids, and interval greedoids. We prove log-concavity …