dorsal/arxiv
View SchemaUnimodular Equivalence of Integral Simplices
| Authors | Feihu Liu, Sihao Tao, Guoce Xin |
|---|---|
| Categories | |
| ArXiv ID | 2601.06819vv1 |
| URL | https://arxiv.org/abs/2601.06819 |
| License | http://creativecommons.org/licenses/by/4.0/ |
Abstract
Testing the unimodular equivalence of two full-dimensional integral simplices can be reduced to testing unimodular permutation (UP) equivalence of two nonsingular matrices. We conduct a systematic study of UP-equivalence, which leads to the first average-case quasi-polynomial time algorithm, called \texttt{HEM}, for deciding the unimodular equivalence of $d$-dimensional integral simplices, as well as achieving a polynomial-time complexity with a failure probability less than $2.5 \times 10^{-7}$. A key ingredient is the introduction of the \emph{permuted Hermite normal form} and its associated \emph{pattern group}, which streamlines the UP-equivalence test by comparing canonical forms derived from induced coset representatives. We also present an acceleration strategy based on Smith normal forms. As a theoretical by-product, we prove that two full-dimensional integral simplices are unimodularly equivalent if and only if their $n$-dimensional pyramids are unimodularly equivalent. This resolves an open question posed by Abney-McPeek et al.
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"abstract": "Testing the unimodular equivalence of two full-dimensional integral simplices can be reduced to testing unimodular permutation (UP) equivalence of two nonsingular matrices. We conduct a systematic study of UP-equivalence, which leads to the first average-case quasi-polynomial time algorithm, called \\texttt{HEM}, for deciding the unimodular equivalence of $d$-dimensional integral simplices, as well as achieving a polynomial-time complexity with a failure probability less than $2.5 \\times 10^{-7}$. A key ingredient is the introduction of the \\emph{permuted Hermite normal form} and its associated \\emph{pattern group}, which streamlines the UP-equivalence test by comparing canonical forms derived from induced coset representatives. We also present an acceleration strategy based on Smith normal forms. As a theoretical by-product, we prove that two full-dimensional integral simplices are unimodularly equivalent if and only if their $n$-dimensional pyramids are unimodularly equivalent. This resolves an open question posed by Abney-McPeek et al.",
"arxiv_id": "2601.06819",
"authors": [
"Feihu Liu",
"Sihao Tao",
"Guoce Xin"
],
"categories": [
"math.CO"
],
"license": "http://creativecommons.org/licenses/by/4.0/",
"title": "Unimodular Equivalence of Integral Simplices",
"url": "https://arxiv.org/abs/2601.06819",
"version": "v1"
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