Sufficient conditions for total positivity, compounds, and Dodgson condensation

Fuente: arXiv
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Autori principali: Fallat, Shaun, Gupta, Himanshu, Johnson, Charles R.
Natura: Preprint
Pubblicazione: 2024
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author Fallat, Shaun
Gupta, Himanshu
Johnson, Charles R.
author_facet Fallat, Shaun
Gupta, Himanshu
Johnson, Charles R.
contents A $n$-by-$n$ matrix is called totally positive ($TP$) if all its minors are positive and $TP_k$ if all of its $k$-by-$k$ submatrices are $TP$. For an arbitrary totally positive matrix or $TP_k$ matrix, we investigate if the $r$th compound ($1<r<n$) is in turn $TP$ or $TP_k$, and demonstrate a strong negative resolution in general. Focus is then shifted to Dodgson's algorithm for calculating the determinant of a generic matrix, and we analyze whether the associated condensed matrices are possibly totally positive or $TP_k$. We also show that all condensed matrices associated with a $TP$ Hankel matrix are $TP$.
format Preprint
id arxiv_https___arxiv_org_abs_2405_06069
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Sufficient conditions for total positivity, compounds, and Dodgson condensation
Fallat, Shaun
Gupta, Himanshu
Johnson, Charles R.
Combinatorics
Rings and Algebras
15B48 (Primary), 15A15, 15A24 (Secondary)
A $n$-by-$n$ matrix is called totally positive ($TP$) if all its minors are positive and $TP_k$ if all of its $k$-by-$k$ submatrices are $TP$. For an arbitrary totally positive matrix or $TP_k$ matrix, we investigate if the $r$th compound ($1<r<n$) is in turn $TP$ or $TP_k$, and demonstrate a strong negative resolution in general. Focus is then shifted to Dodgson's algorithm for calculating the determinant of a generic matrix, and we analyze whether the associated condensed matrices are possibly totally positive or $TP_k$. We also show that all condensed matrices associated with a $TP$ Hankel matrix are $TP$.
title Sufficient conditions for total positivity, compounds, and Dodgson condensation
topic Combinatorics
Rings and Algebras
15B48 (Primary), 15A15, 15A24 (Secondary)
url https://arxiv.org/abs/2405.06069