Matrix Lax pairs under the gauge equivalence relation induced by the gauge group action and Miura-type transformations for lattice equations

Fuente: arXiv
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Main Author: Igonin, Sergei
Format: Preprint
Published: 2024
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_version_ 1866908713496870912
author Igonin, Sergei
author_facet Igonin, Sergei
contents In this paper we explore interconnections of differential-difference matrix Lax representations (Lax pairs), gauge transformations, and discrete Miura-type transformations (MTs), which belong to the main tools in the theory of integrable differential-difference (lattice) equations. For a given equation, two matrix Lax representations (MLRs) are said to be gauge equivalent if one of them can be obtained from the other by means of a (local) matrix gauge transformation. Matrix gauge transformations constitute an infinite-dimensional group called the matrix gauge group, which acts naturally on the set of MLRs of a given equation. Two MLRs are gauge equivalent if and only if they belong to the same orbit of the matrix gauge group action. For a wide class of MLRs of (vector) evolutionary differential-difference equations, we present results on the following questions: 1. When and how can one simplify a given MLR by matrix gauge transformations and bring the MLR to a form suitable for constructing MTs? 2. A MLR is called fake if it is gauge equivalent to a trivial MLR. How to determine whether a given MLR is not fake? This allows us to construct new integrable equations (with new MLRs) connected by new MTs to known equations.
format Preprint
id arxiv_https___arxiv_org_abs_2405_08579
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Matrix Lax pairs under the gauge equivalence relation induced by the gauge group action and Miura-type transformations for lattice equations
Igonin, Sergei
Exactly Solvable and Integrable Systems
37K60, 37K35
In this paper we explore interconnections of differential-difference matrix Lax representations (Lax pairs), gauge transformations, and discrete Miura-type transformations (MTs), which belong to the main tools in the theory of integrable differential-difference (lattice) equations. For a given equation, two matrix Lax representations (MLRs) are said to be gauge equivalent if one of them can be obtained from the other by means of a (local) matrix gauge transformation. Matrix gauge transformations constitute an infinite-dimensional group called the matrix gauge group, which acts naturally on the set of MLRs of a given equation. Two MLRs are gauge equivalent if and only if they belong to the same orbit of the matrix gauge group action. For a wide class of MLRs of (vector) evolutionary differential-difference equations, we present results on the following questions: 1. When and how can one simplify a given MLR by matrix gauge transformations and bring the MLR to a form suitable for constructing MTs? 2. A MLR is called fake if it is gauge equivalent to a trivial MLR. How to determine whether a given MLR is not fake? This allows us to construct new integrable equations (with new MLRs) connected by new MTs to known equations.
title Matrix Lax pairs under the gauge equivalence relation induced by the gauge group action and Miura-type transformations for lattice equations
topic Exactly Solvable and Integrable Systems
37K60, 37K35
url https://arxiv.org/abs/2405.08579