H. Derksen

activity

20242026

collaborators

9 papers

math.AC2026

Generic orbits, normal bases, and generation degree for fields of rational invariants

Ben Blum-Smith, Harm Derksen

For a faithful linear representation $V$ of a finite group $G$ in coprime characteristic, we show that if the field Noether number $I^_{field}^{2}$ is the minimum $d$ such tha…

math.RT2026

Algebraicity of the Brascamp-Lieb constants

Calin Chindris, Harm Derksen

We show that the Brascamp-Lieb (BL) constant BL(-,p) is a semi-algebraic function on the set of feasible data. Consequently, it is algebraic in the sense that it satisfies a polyno…

math.AC2026

Syzygies of the transfer ideal of the symmetric group

Harm Derksen, Alexandra Pevzner

We consider the modular action of the symmetric group $S_{n}$ on $R = k [x_{1}, \dots, x_{n}]$ when $char (k) = p \leq n$ . We show that the image of the transfer map $R \to R^{S_{n}}$ …

quant-ph2026

Constructive counterexamples to the additivity of minimum output RÃ©nyi entropy of quantum channels for all $p > 1$

Harm Derksen, Benjamin Lovitz

We present explicit quantum channels with strictly sub-additive minimum output RÃ©nyi entropy for all $p > 1$ , improving upon prior constructions which handled $p > 2$ . Our example is…

math.AC2025

Tropical Invariants for Permutation Group Actions

Harm Derksen

We consider the action of a permutation group $G$ of order $k$ on the tropical polynomial semiring in $n$ variables. We prove that the sub-semiring of invariant polynomials is fini…

math.RA2025

Invariants of finite groups acting on (free) skew fields

Harm Derksen, Jurij VolÄiÄ

Let $M$ be a finitely generated skew field over a ground field $k$ , and let $G$ be a finite group of $k$ -linear automorphisms of $M$ . This paper investigates finite generation of t…