Nilpotent matrices having a given Jordan type as maximum commuting nilpotent orbit
Abstract
The Jordan type of a nilpotent matrix is the partition giving the sizes of its Jordan blocks. We study pairs of partitions , where is the Jordan type of a generic nilpotent matrix A commuting with a nilpotent matrix B of Jordan type . T. Ko\v{s}ir and P. Oblak have shown that has parts that differ pairwise by at least two. Such partitions, which are also known as "super distinct" or "Rogers-Ramanujan", are exactly those that are stable or "self-large" in the sense that . In 2012 P. Oblak formulated a conjecture concerning the cardinality of the set of partitions such that is a given stable partition with two parts, and proved some special cases. R. Zhao refined this to posit that those partitions such that with could be arranged in an by table where the entry in the -th row and -th column has parts. We prove this Table Theorem, and then generalize the statement to propose a Box Conjecture for the set of partitions for which , for an arbitrary stable partition .
Cite
@article{arxiv.1409.2192,
title = {Nilpotent matrices having a given Jordan type as maximum commuting nilpotent orbit},
author = {Anthony Iarrobino and Leila Khatami and Bart Van Steirteghem and Rui Zhao},
journal= {arXiv preprint arXiv:1409.2192},
year = {2018}
}
Comments
v1: 48 pages, 8 figures ; v2: 61 pages, 7 figures, colors used in tables, improved exposition, details added to some proofs; v3: 48 pages, shortened for submission, then extensively revised for clarity/corrected after substantial referee comments