{"title":"简化具有一般系数的矩阵微分方程","authors":"","doi":"10.1007/s11856-023-2599-0","DOIUrl":null,"url":null,"abstract":"<h3>Abstract</h3> <p>We show that the <em>n × n</em> matrix differential equation <em>δ</em>(<em>Y</em>) = <em>AY</em> with <em>n</em><sup>2</sup> general coefficients cannot be simplified to an equation in less than <em>n</em> parameters by using gauge transformations whose coefficients are rational functions in the matrix entries of <em>A</em> and their derivatives. Our proof uses differential Galois theory and a differential analogue of essential dimension. We also bound the minimum number of parameters needed to describe some generic Picard–Vessiot extensions.</p>","PeriodicalId":0,"journal":{"name":"","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Simplifying matrix differential equations with general coefficients\",\"authors\":\"\",\"doi\":\"10.1007/s11856-023-2599-0\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<h3>Abstract</h3> <p>We show that the <em>n × n</em> matrix differential equation <em>δ</em>(<em>Y</em>) = <em>AY</em> with <em>n</em><sup>2</sup> general coefficients cannot be simplified to an equation in less than <em>n</em> parameters by using gauge transformations whose coefficients are rational functions in the matrix entries of <em>A</em> and their derivatives. Our proof uses differential Galois theory and a differential analogue of essential dimension. We also bound the minimum number of parameters needed to describe some generic Picard–Vessiot extensions.</p>\",\"PeriodicalId\":0,\"journal\":{\"name\":\"\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":0.0,\"publicationDate\":\"2023-12-18\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://doi.org/10.1007/s11856-023-2599-0\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"","FirstCategoryId":"100","ListUrlMain":"https://doi.org/10.1007/s11856-023-2599-0","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
摘要
摘要 我们证明了具有 n2 个一般系数的 n × n 矩阵微分方程 δ(Y) = AY 无法通过使用其系数为 A 的矩阵项中的有理函数及其导数的规整变换简化为小于 n 个参数的方程。我们的证明使用了微分伽罗瓦理论和本质维度的微分类似方法。我们还限定了描述某些一般皮卡-维西奥扩展所需的最小参数数。
Simplifying matrix differential equations with general coefficients
Abstract
We show that the n × n matrix differential equation δ(Y) = AY with n2 general coefficients cannot be simplified to an equation in less than n parameters by using gauge transformations whose coefficients are rational functions in the matrix entries of A and their derivatives. Our proof uses differential Galois theory and a differential analogue of essential dimension. We also bound the minimum number of parameters needed to describe some generic Picard–Vessiot extensions.