H. Derksen

activity

19982026

most citedValuative invariants for polymatroids

64 citations · 346 across the 53 of their papers we have counts for

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10 papers · 1 filter

math.RA2025

Invariants of finite groups acting on (free) skew fields

Harm Derksen, Jurij Volčič

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…

math.RA2024

General Presentations of Algebras and Foundations of $τ$ -tilting Theory

Harm Derksen, Jiarui Fei

In this short note, we explain how the main results in " $τ$ -tilting theory" by Adachi-Iyama-Reiten follow from the results in Section 5 of "General presentations of algebras" by De…

math.RA2021★ 5 cited

Ranks of linear matrix pencils separate simultaneous similarity orbits

Harm Derksen, Igor Klep, Visu Makam +1

This paper solves the two-sided version and provides a counterexample to the general version of the 2003 conjecture by Hadwin and Larson. Consider evaluations of linear matrix penc…

math.RA2018

The regularity lemma is false over small fields

Harm Derksen, Visu Makam

The regularity lemma is a stringent condition of the possible ranks of tensor blow-ups of linear subspaces of matrices. It was proved by Ivanyos, Qiao and Subrahmanyam when the und…

math.RA2018★ 15 cited

Algorithms for orbit closure separation for invariants and semi-invariants of matrices

Harm Derksen, Visu Makam

We consider two group actions on $m$ -tuples of $n \times n$ matrices. The first is simultaneous conjugation by $GL_{n}$ and the second is the left-right action of $\op…

math.RA2017★ 1 cited

Explicit tensors of border rank at least $2 d - 2$ in $K^{d} \otimes K^{d} \otimes K^{d}$ in arbitrary characteristic

Harm Derksen, Visu Makam

For tensors in $C^{d} \otimes C^{d} \otimes C^{d}$ , Landsberg provides non-trivial equations for tensors of border rank $2 d - 3$ for $d$ even and $2 d - 5$ for $d$ …

Invariants of finite groups acting on (free) skew fields

General Presentations of Algebras and Foundations of τ-tilting Theory

Ranks of linear matrix pencils separate simultaneous similarity orbits

The regularity lemma is false over small fields

Algorithms for orbit closure separation for invariants and semi-invariants of matrices

Explicit tensors of border rank at least 2d−2 in Kd⊗Kd⊗Kd in arbitrary characteristic

General Presentations of Algebras and Foundations of $τ$ -tilting Theory

Explicit tensors of border rank at least $2 d - 2$ in $K^{d} \otimes K^{d} \otimes K^{d}$ in arbitrary characteristic