Generic Nullity of Generalized Commutators
Abstract
We study the generic nullity of generalized commutator operators LA(X)=sk+1(A1,⋯,Ak,X) on matrix algebras, where sk+1 denotes the standard polynomial. Dixon and Pressman conjectured an explicit formula for the generic nullity of LA, and Brassil and Reichstein proved the conjecture when k is even. In this paper, we settle the remaining case where k is odd. Our proof first treats the boundary cases k=2n−3 in dimensions n and n+1 using degree decompositions and graph-theoretic interpretations of alternating trace forms, and then establishes a dimension-extension argument from n to n+2. Consequently, together with the result of Brassil and Reichstein, we obtain a complete proof of the Dixon-Pressman generic nullity conjecture over any field of characteristic zero.
Related
- Generic finiteness of solutions to parametrized systems of generalized polynomial inequalities
- Isoperimetric and total curvature inequalities in Cartan-Hadamard manifolds with nullity
- The Morse Index, Nullity and Jacobi Fields of Constant-Curvature Minimal 2-Spheres in Complex Projective Spaces
- Index and nullity of minimal surfaces via representation theory
- A matroid characterization of the combinatorially symmetric maximum nullity of a graph
BibTeX
@misc{lin2026generic,
title = {{Generic Nullity of Generalized Commutators}},
author = {Chen Lin and Chenhao Tang and Enhan Zhao},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.06339},
eprint = {2609.06339},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.06339},
}
RIS
TY - UNPB
TI - Generic Nullity of Generalized Commutators
AU - Chen Lin
AU - Chenhao Tang
AU - Enhan Zhao
PY - 2026
DA - 2026/09/06
PB - arXiv
DO - 10.48550/arxiv.2609.06339
UR - https://arxiv.org/abs/2609.06339
AB - We study the generic nullity of generalized commutator operators L_A(X)=s_k+1(A_1,⋯,A_k,X) on matrix algebras, where s_k+1 denotes the standard polynomial. Dixon and Pressman conjectured an explicit formula for the generic nullity of L_A, and Brassil and Reichstein proved the conjecture when k is even. In this paper, we settle the remaining case where k is odd. Our proof first treats the boundary cases k=2n−3 in dimensions n and n+1 using degree decompositions and graph-theoretic interpretations of alternating trace forms, and then establishes a dimension-extension argument from n to n+2. Consequently, together with the result of Brassil and Reichstein, we obtain a complete proof of the Dixon-Pressman generic nullity conjecture over any field of characteristic zero.
ER -