{"title":"Symmetry breaking operators for the reductive dual pair (Ul,Ul′)","authors":"M. McKee , A. Pasquale , T. Przebinda","doi":"10.1016/j.indag.2024.06.004","DOIUrl":null,"url":null,"abstract":"<div><div>We consider the dual pair <span><math><mrow><mrow><mo>(</mo><mi>G</mi><mo>,</mo><msup><mrow><mi>G</mi></mrow><mrow><mo>′</mo></mrow></msup><mo>)</mo></mrow><mo>=</mo><mrow><mo>(</mo><msub><mrow><mi>U</mi></mrow><mrow><mi>l</mi></mrow></msub><mo>,</mo><msub><mrow><mi>U</mi></mrow><mrow><msup><mrow><mi>l</mi></mrow><mrow><mo>′</mo></mrow></msup></mrow></msub><mo>)</mo></mrow></mrow></math></span> in the symplectic group <span><math><mrow><msub><mrow><mi>Sp</mi></mrow><mrow><mn>2</mn><mi>l</mi><msup><mrow><mi>l</mi></mrow><mrow><mo>′</mo></mrow></msup></mrow></msub><mrow><mo>(</mo><mi>R</mi><mo>)</mo></mrow></mrow></math></span>. Fix a Weil representation of the metaplectic group <span><math><mrow><msub><mrow><mover><mrow><mi>Sp</mi></mrow><mrow><mo>˜</mo></mrow></mover></mrow><mrow><mn>2</mn><mi>l</mi><msup><mrow><mi>l</mi></mrow><mrow><mo>′</mo></mrow></msup></mrow></msub><mrow><mo>(</mo><mi>R</mi><mo>)</mo></mrow></mrow></math></span>. Let <span><math><mover><mrow><mi>G</mi></mrow><mrow><mo>˜</mo></mrow></mover></math></span> and <span><math><msup><mrow><mover><mrow><mi>G</mi></mrow><mrow><mo>˜</mo></mrow></mover></mrow><mrow><mo>′</mo></mrow></msup></math></span> be the preimages of <span><math><mi>G</mi></math></span> and <span><math><msup><mrow><mi>G</mi></mrow><mrow><mo>′</mo></mrow></msup></math></span> in <span><math><mrow><msub><mrow><mover><mrow><mi>Sp</mi></mrow><mrow><mo>˜</mo></mrow></mover></mrow><mrow><mn>2</mn><mi>l</mi><msup><mrow><mi>l</mi></mrow><mrow><mo>′</mo></mrow></msup></mrow></msub><mrow><mo>(</mo><mi>R</mi><mo>)</mo></mrow></mrow></math></span>, and let <span><math><mrow><mi>Π</mi><mo>⊗</mo><msup><mrow><mi>Π</mi></mrow><mrow><mo>′</mo></mrow></msup></mrow></math></span> be a genuine irreducible representation of <span><math><mrow><mover><mrow><mi>G</mi></mrow><mrow><mo>˜</mo></mrow></mover><mo>×</mo><msup><mrow><mover><mrow><mi>G</mi></mrow><mrow><mo>˜</mo></mrow></mover></mrow><mrow><mo>′</mo></mrow></msup></mrow></math></span>. We study the Weyl symbol <span><math><msub><mrow><mi>f</mi></mrow><mrow><mi>Π</mi><mo>⊗</mo><msup><mrow><mi>Π</mi></mrow><mrow><mo>′</mo></mrow></msup></mrow></msub></math></span><span> of the (unique up to a possibly zero constant) symmetry breaking operator (SBO) intertwining the Weil representation with </span><span><math><mrow><mi>Π</mi><mo>⊗</mo><msup><mrow><mi>Π</mi></mrow><mrow><mo>′</mo></mrow></msup></mrow></math></span>. This SBO coincides with the orthogonal projection of the space of the Weil representation onto its <span><math><mi>Π</mi></math></span>-isotypic component and also with the orthogonal projection onto its <span><math><msup><mrow><mi>Π</mi></mrow><mrow><mo>′</mo></mrow></msup></math></span>-isotypic component. Hence <span><math><msub><mrow><mi>f</mi></mrow><mrow><mi>Π</mi><mo>⊗</mo><msup><mrow><mi>Π</mi></mrow><mrow><mo>′</mo></mrow></msup></mrow></msub></math></span> can be computed in two different ways, one using <span><math><mi>Π</mi></math></span> and the other using <span><math><msup><mrow><mi>Π</mi></mrow><mrow><mo>′</mo></mrow></msup></math></span>. By matching the results, we recover Weyl’s theorem stating that <span><math><mrow><mi>Π</mi><mo>⊗</mo><msup><mrow><mi>Π</mi></mrow><mrow><mo>′</mo></mrow></msup></mrow></math></span> occurs in the Weil representation with multiplicity at most one and we also recover the complete list of the representations <span><math><mrow><mi>Π</mi><mo>⊗</mo><msup><mrow><mi>Π</mi></mrow><mrow><mo>′</mo></mrow></msup></mrow></math></span> occurring in Howe’s correspondence.</div></div>","PeriodicalId":56126,"journal":{"name":"Indagationes Mathematicae-New Series","volume":"36 2","pages":"Pages 413-449"},"PeriodicalIF":0.5000,"publicationDate":"2024-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Indagationes Mathematicae-New Series","FirstCategoryId":"100","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0019357724000685","RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"MATHEMATICS","Score":null,"Total":0}
引用次数: 0
Abstract
We consider the dual pair in the symplectic group . Fix a Weil representation of the metaplectic group . Let and be the preimages of and in , and let be a genuine irreducible representation of . We study the Weyl symbol of the (unique up to a possibly zero constant) symmetry breaking operator (SBO) intertwining the Weil representation with . This SBO coincides with the orthogonal projection of the space of the Weil representation onto its -isotypic component and also with the orthogonal projection onto its -isotypic component. Hence can be computed in two different ways, one using and the other using . By matching the results, we recover Weyl’s theorem stating that occurs in the Weil representation with multiplicity at most one and we also recover the complete list of the representations occurring in Howe’s correspondence.
期刊介绍:
Indagationes Mathematicae is a peer-reviewed international journal for the Mathematical Sciences of the Royal Dutch Mathematical Society. The journal aims at the publication of original mathematical research papers of high quality and of interest to a large segment of the mathematics community. The journal also welcomes the submission of review papers of high quality.