{"title":"Centralizers of Nilpotent Elements in Basic Classical Lie Superalgebras in Good Characteristic","authors":"Leyu Han","doi":"10.1007/s00031-023-09814-3","DOIUrl":null,"url":null,"abstract":"Abstract Let $$\\mathfrak {g}=\\mathfrak {g}_{\\bar{0}}\\oplus \\mathfrak {g}_{\\bar{1}}$$ <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:mrow> <mml:mi>g</mml:mi> <mml:mo>=</mml:mo> <mml:msub> <mml:mi>g</mml:mi> <mml:mover> <mml:mrow> <mml:mn>0</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>¯</mml:mo> </mml:mrow> </mml:mover> </mml:msub> <mml:mo>⊕</mml:mo> <mml:msub> <mml:mi>g</mml:mi> <mml:mover> <mml:mrow> <mml:mn>1</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>¯</mml:mo> </mml:mrow> </mml:mover> </mml:msub> </mml:mrow> </mml:math> be a basic classical Lie superalgebra over an algebraically closed field $$\\mathbb {K}$$ <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:mi>K</mml:mi> </mml:math> whose characteristic $$p>0$$ <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:mrow> <mml:mi>p</mml:mi> <mml:mo>></mml:mo> <mml:mn>0</mml:mn> </mml:mrow> </mml:math> is a good prime for $$\\mathfrak {g}$$ <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:mi>g</mml:mi> </mml:math> . Let $$G_{\\bar{0}}$$ <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:msub> <mml:mi>G</mml:mi> <mml:mover> <mml:mrow> <mml:mn>0</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>¯</mml:mo> </mml:mrow> </mml:mover> </mml:msub> </mml:math> be the reductive algebraic group over $$\\mathbb {K}$$ <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:mi>K</mml:mi> </mml:math> such that $$\\textrm{Lie}(G_{\\bar{0}})=\\mathfrak {g}_{\\bar{0}}$$ <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:mrow> <mml:mtext>Lie</mml:mtext> <mml:mrow> <mml:mo>(</mml:mo> <mml:msub> <mml:mi>G</mml:mi> <mml:mover> <mml:mrow> <mml:mn>0</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>¯</mml:mo> </mml:mrow> </mml:mover> </mml:msub> <mml:mo>)</mml:mo> </mml:mrow> <mml:mo>=</mml:mo> <mml:msub> <mml:mi>g</mml:mi> <mml:mover> <mml:mrow> <mml:mn>0</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>¯</mml:mo> </mml:mrow> </mml:mover> </mml:msub> </mml:mrow> </mml:math> . Suppose $$e\\in \\mathfrak {g}_{\\bar{0}}$$ <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:mrow> <mml:mi>e</mml:mi> <mml:mo>∈</mml:mo> <mml:msub> <mml:mi>g</mml:mi> <mml:mover> <mml:mrow> <mml:mn>0</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>¯</mml:mo> </mml:mrow> </mml:mover> </mml:msub> </mml:mrow> </mml:math> is nilpotent. Write $$\\mathfrak {g}^{e}$$ <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:msup> <mml:mrow> <mml:mi>g</mml:mi> </mml:mrow> <mml:mi>e</mml:mi> </mml:msup> </mml:math> for the centralizer of e in $$\\mathfrak {g}$$ <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:mi>g</mml:mi> </mml:math> and $$\\mathfrak {z}(\\mathfrak {g}^{e})$$ <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:mrow> <mml:mi>z</mml:mi> <mml:mo>(</mml:mo> <mml:msup> <mml:mrow> <mml:mi>g</mml:mi> </mml:mrow> <mml:mi>e</mml:mi> </mml:msup> <mml:mo>)</mml:mo> </mml:mrow> </mml:math> for the centre of $$\\mathfrak {g}^{e}$$ <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:msup> <mml:mrow> <mml:mi>g</mml:mi> </mml:mrow> <mml:mi>e</mml:mi> </mml:msup> </mml:math> . We calculate a basis for $$\\mathfrak {g}^{e}$$ <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:msup> <mml:mrow> <mml:mi>g</mml:mi> </mml:mrow> <mml:mi>e</mml:mi> </mml:msup> </mml:math> and $$\\mathfrak {z}(\\mathfrak {g}^{e})$$ <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:mrow> <mml:mi>z</mml:mi> <mml:mo>(</mml:mo> <mml:msup> <mml:mrow> <mml:mi>g</mml:mi> </mml:mrow> <mml:mi>e</mml:mi> </mml:msup> <mml:mo>)</mml:mo> </mml:mrow> </mml:math> by using associated cocharacters $$\\tau :\\mathbb {K}^{\\times }\\rightarrow G_{\\bar{0}}$$ <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:mrow> <mml:mi>τ</mml:mi> <mml:mo>:</mml:mo> <mml:msup> <mml:mrow> <mml:mi>K</mml:mi> </mml:mrow> <mml:mo>×</mml:mo> </mml:msup> <mml:mo>→</mml:mo> <mml:msub> <mml:mi>G</mml:mi> <mml:mover> <mml:mrow> <mml:mn>0</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>¯</mml:mo> </mml:mrow> </mml:mover> </mml:msub> </mml:mrow> </mml:math> of e . In addition, we give the classification of e which are reachable, strongly reachable or satisfy the Panyushev property for exceptional Lie superalgebras $$D(2,1;\\alpha )$$ <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:mrow> <mml:mi>D</mml:mi> <mml:mo>(</mml:mo> <mml:mn>2</mml:mn> <mml:mo>,</mml:mo> <mml:mn>1</mml:mn> <mml:mo>;</mml:mo> <mml:mi>α</mml:mi> <mml:mo>)</mml:mo> </mml:mrow> </mml:math> , G (3) and F (4).","PeriodicalId":0,"journal":{"name":"","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1007/s00031-023-09814-3","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
Abstract Let $$\mathfrak {g}=\mathfrak {g}_{\bar{0}}\oplus \mathfrak {g}_{\bar{1}}$$ g=g0¯⊕g1¯ be a basic classical Lie superalgebra over an algebraically closed field $$\mathbb {K}$$ K whose characteristic $$p>0$$ p>0 is a good prime for $$\mathfrak {g}$$ g . Let $$G_{\bar{0}}$$ G0¯ be the reductive algebraic group over $$\mathbb {K}$$ K such that $$\textrm{Lie}(G_{\bar{0}})=\mathfrak {g}_{\bar{0}}$$ Lie(G0¯)=g0¯ . Suppose $$e\in \mathfrak {g}_{\bar{0}}$$ e∈g0¯ is nilpotent. Write $$\mathfrak {g}^{e}$$ ge for the centralizer of e in $$\mathfrak {g}$$ g and $$\mathfrak {z}(\mathfrak {g}^{e})$$ z(ge) for the centre of $$\mathfrak {g}^{e}$$ ge . We calculate a basis for $$\mathfrak {g}^{e}$$ ge and $$\mathfrak {z}(\mathfrak {g}^{e})$$ z(ge) by using associated cocharacters $$\tau :\mathbb {K}^{\times }\rightarrow G_{\bar{0}}$$ τ:K×→G0¯ of e . In addition, we give the classification of e which are reachable, strongly reachable or satisfy the Panyushev property for exceptional Lie superalgebras $$D(2,1;\alpha )$$ D(2,1;α) , G (3) and F (4).