{"title":"由规范群作用诱导的规范等价关系下的矩阵Lax对和格方程的miura型变换","authors":"Sergei Igonin","doi":"10.1016/j.geomphys.2025.105585","DOIUrl":null,"url":null,"abstract":"<div><div>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.</div><div>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.</div><div>For a wide class of MLRs of (vector) evolutionary differential-difference equations, we present results on the following questions:<ul><li><span>1.</span><span><div>When and how can one simplify a given MLR by matrix gauge transformations and bring the MLR to a form suitable for constructing MTs?</div></span></li><li><span>2.</span><span><div>A MLR is called fake if it is gauge equivalent to a trivial MLR. How to determine whether a given MLR is not fake?</div></span></li></ul></div><div>Here and in a different publication (with E. Chistov), we apply results of the present paper to the following integrable examples:<ul><li><span>•</span><span><div>a 3-component lattice introduced by D. Zhang and D. Chen in their work on Hamiltonian structures of evolutionary lattice equations <span><span>[28]</span></span>,</div></span></li><li><span>•</span><span><div>some rational 1-component equations of order <span><math><mo>(</mo><mo>−</mo><mn>2</mn><mo>,</mo><mn>2</mn><mo>)</mo></math></span> related to the Narita–Itoh–Bogoyavlensky lattice,</div></span></li><li><span>•</span><span><div>the 2-component Boussinesq lattice related to the lattice <span><math><msub><mrow><mi>W</mi></mrow><mrow><mn>3</mn></mrow></msub></math></span>-algebra,</div></span></li><li><span>•</span><span><div>a 2-component equation (introduced by G. Marí Beffa and Jing Ping Wang in their work on Hamiltonian evolutions of polygons <span><span>[2]</span></span>) which describes the evolution induced on invariants by an invariant evolution of planar polygons.</div></span></li></ul> This allows us to construct new integrable equations (with new MLRs) connected by new MTs to known equations.</div></div>","PeriodicalId":55602,"journal":{"name":"Journal of Geometry and Physics","volume":"216 ","pages":"Article 105585"},"PeriodicalIF":1.2000,"publicationDate":"2025-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Matrix Lax pairs under the gauge equivalence relation induced by the gauge group action and Miura-type transformations for lattice equations\",\"authors\":\"Sergei Igonin\",\"doi\":\"10.1016/j.geomphys.2025.105585\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>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.</div><div>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.</div><div>For a wide class of MLRs of (vector) evolutionary differential-difference equations, we present results on the following questions:<ul><li><span>1.</span><span><div>When and how can one simplify a given MLR by matrix gauge transformations and bring the MLR to a form suitable for constructing MTs?</div></span></li><li><span>2.</span><span><div>A MLR is called fake if it is gauge equivalent to a trivial MLR. How to determine whether a given MLR is not fake?</div></span></li></ul></div><div>Here and in a different publication (with E. Chistov), we apply results of the present paper to the following integrable examples:<ul><li><span>•</span><span><div>a 3-component lattice introduced by D. Zhang and D. Chen in their work on Hamiltonian structures of evolutionary lattice equations <span><span>[28]</span></span>,</div></span></li><li><span>•</span><span><div>some rational 1-component equations of order <span><math><mo>(</mo><mo>−</mo><mn>2</mn><mo>,</mo><mn>2</mn><mo>)</mo></math></span> related to the Narita–Itoh–Bogoyavlensky lattice,</div></span></li><li><span>•</span><span><div>the 2-component Boussinesq lattice related to the lattice <span><math><msub><mrow><mi>W</mi></mrow><mrow><mn>3</mn></mrow></msub></math></span>-algebra,</div></span></li><li><span>•</span><span><div>a 2-component equation (introduced by G. Marí Beffa and Jing Ping Wang in their work on Hamiltonian evolutions of polygons <span><span>[2]</span></span>) which describes the evolution induced on invariants by an invariant evolution of planar polygons.</div></span></li></ul> This allows us to construct new integrable equations (with new MLRs) connected by new MTs to known equations.</div></div>\",\"PeriodicalId\":55602,\"journal\":{\"name\":\"Journal of Geometry and Physics\",\"volume\":\"216 \",\"pages\":\"Article 105585\"},\"PeriodicalIF\":1.2000,\"publicationDate\":\"2025-07-05\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Geometry and Physics\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S039304402500169X\",\"RegionNum\":3,\"RegionCategory\":\"数学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"MATHEMATICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Geometry and Physics","FirstCategoryId":"100","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S039304402500169X","RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MATHEMATICS","Score":null,"Total":0}
Matrix Lax pairs under the gauge equivalence relation induced by the gauge group action and Miura-type transformations for lattice equations
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?
Here and in a different publication (with E. Chistov), we apply results of the present paper to the following integrable examples:
•
a 3-component lattice introduced by D. Zhang and D. Chen in their work on Hamiltonian structures of evolutionary lattice equations [28],
•
some rational 1-component equations of order related to the Narita–Itoh–Bogoyavlensky lattice,
•
the 2-component Boussinesq lattice related to the lattice -algebra,
•
a 2-component equation (introduced by G. Marí Beffa and Jing Ping Wang in their work on Hamiltonian evolutions of polygons [2]) which describes the evolution induced on invariants by an invariant evolution of planar polygons.
This allows us to construct new integrable equations (with new MLRs) connected by new MTs to known equations.
期刊介绍:
The Journal of Geometry and Physics is an International Journal in Mathematical Physics. The Journal stimulates the interaction between geometry and physics by publishing primary research, feature and review articles which are of common interest to practitioners in both fields.
The Journal of Geometry and Physics now also accepts Letters, allowing for rapid dissemination of outstanding results in the field of geometry and physics. Letters should not exceed a maximum of five printed journal pages (or contain a maximum of 5000 words) and should contain novel, cutting edge results that are of broad interest to the mathematical physics community. Only Letters which are expected to make a significant addition to the literature in the field will be considered.
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