Dualities and Representations of Lie Superalgebras (cid:15)(cid:13)(cid:18)(cid:9)(cid:19)(cid:20)(cid:4)(cid:9)(cid:10)(cid:21)(cid:13)(cid:4)(cid:9)(cid:22) (cid:23)(cid:4)(cid:6)(cid:24)(cid:6)(cid:8)(cid:9)(cid:22)(cid:10)(cid:23)(cid:8)(cid:9)(cid:22) (cid:25)(cid:5)(cid:8)(cid:26)(cid:18)(cid:8)(cid:12)(cid:4)(cid:10)(cid:15)(cid:12)(cid:18)(cid:26)(cid:6)(cid:4)(cid:27)(cid:10) (cid:6)(cid:9)(cid:10)(cid:11)(cid:8)(cid:12)(cid:13)(cid:4)(cid:3)(cid:8)(cid:12)(cid:6)(cid:7)(cid:27) (cid:28)(cid:16)(cid:14)(cid:18)(cid:3)(cid:4)(cid:10)(cid:29)(cid:30)(cid:30) (cid:2)(cid:3)(cid:4)(cid:5)(cid:6)(cid:7)(cid:8)(cid:9)(cid:10)(cid:11)(cid:8)(cid:12)(cid:13)(cid:4)(cid:3)(cid:8)(cid:12)(cid:6)(cid:7)(cid:8)(cid:14)(cid:10)(cid:15)(cid:16)(cid:7)(cid:6)(cid:4)(cid:12)(cid:17) Dualities and Representations of Lie Superalgebras Dualities and Representations of Lie Superalgebras Shun-Jen Cheng Weiqiang Wang Graduate Studies in Mathematics Volume 144 American Mathematical Society Providence, Rhode Island EDITORIAL COMMITTEE David Cox (Chair) Daniel S. Freed Rafe Mazzeo Gigliola Staffilani 2010 Mathematics Subject Classification. Primary 17B10, 17B20. For additional informationand updates on this book, visit www.ams.org/bookpages/gsm-144 Library of Congress Cataloging-in-Publication Data Cheng,Shun-Jen,1963– DualitiesandrepresentationsofLiesuperalgebras/Shun-JenCheng,WeiqiangWang. pagescm. —(Graduatestudiesinmathematics;volume144) Includesbibliographicalreferencesandindex. ISBN978-0-8218-9118-6(alk.paper) 1.Liesuperalgebras. 2.Dualitytheory(Mathematics) I.Wang,Weiqiang,1970– II.Title. QA252.3.C44 2013 512(cid:2).482—dc23 2012031989 Copying and reprinting. Individual readers of this publication, and nonprofit libraries actingforthem,arepermittedtomakefairuseofthematerial,suchastocopyachapterforuse in teaching or research. Permission is granted to quote brief passages from this publication in reviews,providedthecustomaryacknowledgmentofthesourceisgiven. Republication,systematiccopying,ormultiplereproductionofanymaterialinthispublication is permitted only under license from the American Mathematical Society. Requests for such permissionshouldbeaddressedtotheAcquisitionsDepartment,AmericanMathematicalSociety, 201 Charles Street, Providence, Rhode Island 02904-2294 USA. Requests can also be made by [email protected]. (cid:2)c 2012bytheAmericanMathematicalSociety. Allrightsreserved. TheAmericanMathematicalSocietyretainsallrights exceptthosegrantedtotheUnitedStatesGovernment. PrintedintheUnitedStatesofAmerica. (cid:2)∞ Thepaperusedinthisbookisacid-freeandfallswithintheguidelines establishedtoensurepermanenceanddurability. VisittheAMShomepageathttp://www.ams.org/ 10987654321 171615141312 ToMei-Hui,Xiaohui,Isabelle,andourparents Contents Preface xiii Chapter1. LiesuperalgebraABC 1 §1.1. Liesuperalgebras: Definitionsandexamples 1 1.1.1. Basicdefinitions 2 1.1.2. ThegeneralandspeciallinearLiesuperalgebras 4 1.1.3. Theortho-symplecticLiesuperalgebras 6 1.1.4. ThequeerLiesuperalgebras 8 1.1.5. TheperiplecticandexceptionalLiesuperalgebras 9 1.1.6. TheCartanseries 10 1.1.7. Theclassificationtheorem 12 §1.2. StructuresofclassicalLiesuperalgebras 13 1.2.1. Abasicstructuretheorem 13 1.2.2. Invariantbilinearformsforglandosp 16 1.2.3. RootsystemandWeylgroupforgl(m|n) 16 1.2.4. RootsystemandWeylgroupforspo(2m|2n+1) 17 1.2.5. RootsystemandWeylgroupforspo(2m|2n) 17 1.2.6. Rootsystemandoddinvariantformforq(n) 18 §1.3. Non-conjugatepositivesystemsandoddreflections 19 1.3.1. Positivesystemsandfundamentalsystems 19 1.3.2. Positiveandfundamentalsystemsforgl(m|n) 21 1.3.3. Positiveandfundamentalsystemsforspo(2m|2n+1) 22 1.3.4. Positiveandfundamentalsystemsforspo(2m|2n) 23 1.3.5. Conjugacyclassesoffundamentalsystems 25 §1.4. Oddandrealreflections 26 1.4.1. Afundamentallemma 26 vii viii Contents 1.4.2. Oddreflections 27 1.4.3. Realreflections 28 1.4.4. Reflectionsandfundamentalsystems 28 1.4.5. Examples 30 §1.5. Highestweighttheory 31 1.5.1. ThePoincare´-Birkhoff-Witt(PBW)Theorem 31 1.5.2. RepresentationsofsolvableLiesuperalgebras 32 1.5.3. HighestweighttheoryforbasicLiesuperalgebras 33 1.5.4. Highestweighttheoryforq(n) 35 §1.6. Exercises 37 Notes 40 Chapter2. Finite-dimensionalmodules 43 §2.1. Classificationoffinite-dimensionalsimplemodules 43 2.1.1. Finite-dimensionalsimplemodulesofgl(m|n) 43 2.1.2. Finite-dimensionalsimplemodulesofspo(2m|2) 45 2.1.3. Avirtualcharacterformula 45 2.1.4. Finite-dimensionalsimplemodulesofspo(2m|2n+1) 47 2.1.5. Finite-dimensionalsimplemodulesofspo(2m|2n) 50 2.1.6. Finite-dimensionalsimplemodulesofq(n) 53 §2.2. Harish-Chandrahomomorphismandlinkage 55 2.2.1. Supersymmetrization 55 2.2.2. Centralcharacters 56 2.2.3. Harish-ChandrahomomorphismforbasicLiesuperalgebras 57 2.2.4. Invariantpolynomialsforglandosp 59 2.2.5. ImageofHarish-Chandrahomomorphismforglandosp 62 2.2.6. Linkageforglandosp 65 2.2.7. Typicalfinite-dimensionalirreduciblecharacters 68 §2.3. Harish-Chandrahomomorphismandlinkageforq(n) 69 2.3.1. Centralcharactersforq(n) 70 2.3.2. Harish-Chandrahomomorphismforq(n) 70 2.3.3. Linkageforq(n) 74 2.3.4. Typicalfinite-dimensionalcharactersofq(n) 76 §2.4. Extremalweightsoffinite-dimensionalsimplemodules 77 2.4.1. Extremalweightsforgl(m|n) 77 2.4.2. Extremalweightsforspo(2m|2n+1) 80 2.4.3. Extremalweightsforspo(2m|2n) 82 §2.5. Exercises 85 Notes 89 Chapter3. Schurduality 91 Contents ix §3.1. Generalitiesforassociativesuperalgebras 91 3.1.1. Classificationofsimplesuperalgebras 92 3.1.2. WedderburnTheoremandSchur’sLemma 94 3.1.3. Doublecentralizerpropertyforsuperalgebras 95 3.1.4. Splitconjugacyclassesinafinitesupergroup 96 §3.2. Schur-SergeevdualityoftypeA 98 3.2.1. Schur-Sergeevduality,I 98 3.2.2. Schur-Sergeevduality,II 100 3.2.3. Thecharacterformula 104 3.2.4. TheclassicalSchurduality 105 3.2.5. Degreeofatypicalityofλ(cid:2) 106 3.2.6. Categoryofpolynomialmodules 108 §3.3. RepresentationtheoryofthealgebraH 109 n 3.3.1. Adoublecover 110 (cid:2) 3.3.2. SplitconjugacyclassesinB 111 n − 3.3.3. AringstructureonR 114 3.3.4. Thecharacteristicmap 116 3.3.5. Thebasicspinmodule 118 3.3.6. Theirreduciblecharacters 119 §3.4. Schur-Sergeevdualityforq(n) 121 3.4.1. Adoublecentralizerproperty 121 3.4.2. TheSergeevduality 123 3.4.3. Theirreduciblecharacterformula 125 §3.5. Exercises 125 Notes 128 Chapter4. Classicalinvarianttheory 131 §4.1. FFTforthegenerallinearLiegroup 131 4.1.1. Generalinvarianttheory 132 4.1.2. TensorandmultilinearFFTforGL(V) 133 4.1.3. FormulationofthepolynomialFFTforGL(V) 134 4.1.4. Polarizationandrestitution 135 §4.2. PolynomialFFTforclassicalgroups 137 4.2.1. AreductiontheoremofWeyl 137 4.2.2. Thesymplecticandorthogonalgroups 139 4.2.3. FormulationofthepolynomialFFT 140 4.2.4. FrombasictogeneralpolynomialFFT 141 4.2.5. Thebasiccase 142 §4.3. TensorandsupersymmetricFFTforclassicalgroups 145 4.3.1. TensorFFTforclassicalgroups 145 4.3.2. FromtensorFFTtosupersymmetricFFT 147