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math.CO2026

Two Linear Programs are Better than One

Alexander E. Black, Christoph Hertrich, Stefan Kober +1

The extension complexity of a polytope is the minimum number of facets of a polytope that projects onto it. Motivated by the complexity of neural network…

math.CO2026

Monotone Diameters of Lattice Polytopes

Alexander E. Black

An influential 1989 result of Naddef shows that the diameters of -polytopes are at most their dimension. This was extended shortly after by Kleinschmidt and Onn to any lattice…

math.CO2026

Any Proof of Polynomial Hirsch Must be Completely Incoherent

Alexander E. Black, Lei Xue

In 1992, Billera and Sturmfels introduced coherent monotone paths on polytopes as part of their description of the fiber polytope construction, and later in 1994 showed with Kapran…

math.CO2025

Saturation for Non-Symmetric Macdonald Polynomials

Milo Bechtloff Weising, Alexander E. Black

We prove that supports of non-symmetric Macdonald polynomials are -convex. As a consequence, we resolve a 2019 conjecture of Monical, Tokcan, and Yong that they have the saturat…

math.CO2024

Random Shadows of Fixed Polytopes

Alexander E. Black, Francisco Criado

Estimating the number of vertices of a two dimensional projection, called a shadow, of a polytope is a fundamental tool for understanding the performance of the shadow simplex meth…

math.CO2024

From linear programming to colliding particles

Alexander E. Black, Niklas Lütjeharms, Raman Sanyal

Although simplices are trivial from a linear optimization standpoint, the simplex algorithm can exhibit quite complex behavior. In this paper we study the behavior of max-slope piv…