{"title":"\\(C^*\\) -代数正锥上映射的Jordan \\(*\\) -同构的非线性表征","authors":"Osamu Hatori, Shiho Oi","doi":"10.1007/s44146-024-00140-y","DOIUrl":null,"url":null,"abstract":"<div><p>We study maps between positive definite or positive semidefinite cones of unital <span>\\(C^*\\)</span>-algebras. We describe surjective maps that preserve </p><ol>\n <li>\n <span>(1)</span>\n \n <p>the norm of the quotient or product of elements;</p>\n \n </li>\n <li>\n <span>(2)</span>\n \n <p>the spectrum of the quotient or product of elements;</p>\n \n </li>\n <li>\n <span>(3)</span>\n \n <p>the spectral seminorm of the quotient or product of elements.</p>\n \n </li>\n </ol><p> These maps relate to the Jordan <span>\\(*\\)</span>-isomorphisms between the specified <span>\\(C^*\\)</span>-algebras. While a surjection between positive definite cones that preserves the norm of the quotient of elements may not be extended to a linear map between the underlying <span>\\(C^*\\)</span>-algebras, the other types of surjections can be extended to a Jordan <span>\\(*\\)</span>-isomorphism or a Jordan <span>\\(*\\)</span>-isomorphism followed by 2-sided multiplication by a positive invertible element. We also study conditions for the centrality of positive invertible elements. We generalize “the corollary” regarding surjections between positive semidefinite cones of unital <span>\\(C^*\\)</span>-algebras. Applying it, we provide positive solutions to the problem posed by Molnár for general unital <span>\\(C^*\\)</span>-algebras.</p></div>","PeriodicalId":46939,"journal":{"name":"ACTA SCIENTIARUM MATHEMATICARUM","volume":"91 1-2","pages":"313 - 336"},"PeriodicalIF":0.6000,"publicationDate":"2024-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Non-linear characterization of Jordan \\\\(*\\\\)-isomorphisms via maps on positive cones of \\\\(C^*\\\\)-algebras\",\"authors\":\"Osamu Hatori, Shiho Oi\",\"doi\":\"10.1007/s44146-024-00140-y\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>We study maps between positive definite or positive semidefinite cones of unital <span>\\\\(C^*\\\\)</span>-algebras. We describe surjective maps that preserve </p><ol>\\n <li>\\n <span>(1)</span>\\n \\n <p>the norm of the quotient or product of elements;</p>\\n \\n </li>\\n <li>\\n <span>(2)</span>\\n \\n <p>the spectrum of the quotient or product of elements;</p>\\n \\n </li>\\n <li>\\n <span>(3)</span>\\n \\n <p>the spectral seminorm of the quotient or product of elements.</p>\\n \\n </li>\\n </ol><p> These maps relate to the Jordan <span>\\\\(*\\\\)</span>-isomorphisms between the specified <span>\\\\(C^*\\\\)</span>-algebras. While a surjection between positive definite cones that preserves the norm of the quotient of elements may not be extended to a linear map between the underlying <span>\\\\(C^*\\\\)</span>-algebras, the other types of surjections can be extended to a Jordan <span>\\\\(*\\\\)</span>-isomorphism or a Jordan <span>\\\\(*\\\\)</span>-isomorphism followed by 2-sided multiplication by a positive invertible element. We also study conditions for the centrality of positive invertible elements. We generalize “the corollary” regarding surjections between positive semidefinite cones of unital <span>\\\\(C^*\\\\)</span>-algebras. Applying it, we provide positive solutions to the problem posed by Molnár for general unital <span>\\\\(C^*\\\\)</span>-algebras.</p></div>\",\"PeriodicalId\":46939,\"journal\":{\"name\":\"ACTA SCIENTIARUM MATHEMATICARUM\",\"volume\":\"91 1-2\",\"pages\":\"313 - 336\"},\"PeriodicalIF\":0.6000,\"publicationDate\":\"2024-05-27\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"ACTA SCIENTIARUM MATHEMATICARUM\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://link.springer.com/article/10.1007/s44146-024-00140-y\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"MATHEMATICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"ACTA SCIENTIARUM MATHEMATICARUM","FirstCategoryId":"1085","ListUrlMain":"https://link.springer.com/article/10.1007/s44146-024-00140-y","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"MATHEMATICS","Score":null,"Total":0}
Non-linear characterization of Jordan \(*\)-isomorphisms via maps on positive cones of \(C^*\)-algebras
We study maps between positive definite or positive semidefinite cones of unital \(C^*\)-algebras. We describe surjective maps that preserve
(1)
the norm of the quotient or product of elements;
(2)
the spectrum of the quotient or product of elements;
(3)
the spectral seminorm of the quotient or product of elements.
These maps relate to the Jordan \(*\)-isomorphisms between the specified \(C^*\)-algebras. While a surjection between positive definite cones that preserves the norm of the quotient of elements may not be extended to a linear map between the underlying \(C^*\)-algebras, the other types of surjections can be extended to a Jordan \(*\)-isomorphism or a Jordan \(*\)-isomorphism followed by 2-sided multiplication by a positive invertible element. We also study conditions for the centrality of positive invertible elements. We generalize “the corollary” regarding surjections between positive semidefinite cones of unital \(C^*\)-algebras. Applying it, we provide positive solutions to the problem posed by Molnár for general unital \(C^*\)-algebras.