PDF Download Representations of Elementary Abelian P-Groups And

Total Page:16

File Type:pdf, Size:1020Kb

PDF Download Representations of Elementary Abelian P-Groups And REPRESENTATIONS OF ELEMENTARY ABELIAN P- GROUPS AND VECTOR BUNDLES 1ST EDITION PDF, EPUB, EBOOK David J Benson | 9781107174177 | | | | | Representations of Elementary Abelian P-Groups and Vector Bundles 1st edition PDF Book Jump to: navigation , search. If the answer to this zeroth question is negative, then my actual "number one" question would be whether there is a classification of such representations. Active Oldest Votes. Rose Sociality As The Human Sign up using Facebook. We show that special classes of restricted representations of g lead to algebraic vector bundles on E r ,g. Viewed times. Friedlander , J. What is the correct notion of representation for abelian varieties? Friedlander and A. We prove finite generation of the cohomology ring of any finite dimensional pointed Hopf algebra, having abelian group of grouplike elements, under some mild restrictions on the group order. To follow this analogy then, one should view line bundles on an abelian variety as some sort of its 1-dimensional representations. All photos are panoramic, and each spreads over 3 double- pages. Phenomenology of modules over elementary abelian p-groups; A. We introduce the notion of -cosupport as a new tool for the stable module category of a finite group scheme. Namespaces Article Talk. In characteristic zero we relate it to the canonical dimension of certain products of Weil transfers of generalized Severi-Brauer varieties. Dual of a vector space, as well as the Pontryagin dual of an abelian group can be viewed as the set of its 1-dimensional representations, with appropriate structure. There is then a canonical pairing. We also introduce modules of constant radical and socle type generalizing modules of constant Jordan type and provide several general constructions of modules with these properties. English French German Italian Spanish. Active 1 month ago. Karpenko and Z. Bright Modernity: Color, Commerce, As a consequence, we prove analogues of classical theorems of R. Popular groups Symmetric group:S3 order 3! Each such T can be considered as a group homomorphism from V to V an endomorphism and likewise any endomorphism of V can be considered as a linear transformation of V as a vector space. The appendix gives a constructive version of this result. Reichstein , Commentarii Math. View specific information such as linear representation theory, subgroup structure about this group View a complete list of particular groups this is a very huge list! Facts is your complete guide to Elementary Statistics. Representations of Elementary Abelian P-Groups and Vector Bundles 1st edition Writer Schauenburg and S. Vector bundles on projective space; 7. In the case of a finite group, we use this to give a new proof of the classification of tensor ideal localising subcategories. Bright Modernity: Color, Commerce, Libli Libli 4, 12 12 silver badges 28 28 bronze badges. April Learn how and when to remove this template message. Restrictions coming from Chern numbers; Algebraic groups Linear algebraic group Reductive group Abelian variety Elliptic curve. Qiaochu Yuan Qiaochu Yuan Sign up or log in Sign up using Google. A Course on Finite Groups. He has authored a number of books, including Representations and Cohomology Cambridge, and Polynomial Invariants of Finite Groups Cambridge, Abstract: This is a survey article covering developments in representation theory of finite group schemes over the last fifteen years. This article may require cleanup to meet Wikipedia's quality standards. Jordan type; 5. Asia On Tour: Exploring In this book, you will learn topics In general, a possibly infinite elementary abelian p -group is a direct sum of cyclic groups of order p. From Wikipedia, the free encyclopedia. The material is mostly complementary to the article of D. This book is a reproduction of the original book published in and may have some imperfections such as marks or hand-written notes. Representations of Elementary Abelian P-Groups and Vector Bundles 1st edition Reviews The specific problem is: do not assume finite unless stated Please help improve this article if you can. Modules of constant Jordan type; 6. Each such T can be considered as a group homomorphism from V to V an endomorphism and likewise any endomorphism of V can be considered as a linear transformation of V as a vector space. Modules of constant Jordan type and vector bundles; 9. Related 8. Papers, preprints and other things. Popular groups Symmetric group:S3 order 3! Enabling JavaScript in your browser will allow you to experience all the features of our site. Questions about modular representation theory of finite groups can often be reduced to elementary abelian subgroups. Help Learn to edit Community portal Recent changes Upload file. Schauenburg and S. These varieties E r ,g are the natural ambient varieties for generalized support varieties for restricted representations of g. Every elementary abelian p -group is a vector space over the prime field with p elements, and conversely every such vector space is an elementary abelian group. It contains all modules in an Auslander-Reiten component which has at least one module in the class. We also verify that our representation-theoretic definition of support cones admits an interpretation in terms of Rickard idempotent modules associated to thick subcategories of the stable category of finite dimensional modules. Background from algebraic geometry; 4. These are sheaves on locally closed subvarieties of the projective variety E r ,g of elementary subalgebras of g of dimension r. Extensive background material is provided, which will help the reader to understand vector bundles and their Chern classes from an algebraic point of view, and to apply this to modular representation theory of elementary abelian groups. PDF file. Cyclic groups of order p; 3. We show that representations of constant radical or socle rank studied in [CFP3] which generalize modules of constant Jordan type lead to algebraic vector bundles on E r,g. The file roots. As a consequence, we prove analogues of classical theorems of R. The statements are motivated by, and are analogues of, similar results for finite groups and finite group schemes, but the structure of elementary supergroups schemes necessary for detection is more complicated than in either of these cases. Add to Wishlist. Though I am not an expert, I believe that for abelian varieties it goes the other way round. For instance, we can use the following assignment in GAP to create the group and name it :. This is the first book to offer a detailed study of the representation theory of elementary abelian groups, bringing together information from many papers and journals, as well as unpublished research. Sign up to join this community. For a better shopping experience, please upgrade now. The best answers are voted up and rise to the top. We start with the finite generation of cohomology of a finite group scheme and proceed to discuss various consequences and theories that ultimately grew out of that result. Infinite Abelian Groups. We also show that in general the cohomology ring of a Hopf algebra in a braided category is braided commutative. We prove finite generation of the cohomology ring of any finite dimensional pointed Hopf algebra, having abelian group of grouplike elements, under some mild restrictions on the group order. If the answer to this zeroth question is negative, then my actual "number one" question would be whether there is a classification of such representations. Cambridge Tracts in Mathematics , Representations of Elementary Abelian P-Groups and Vector Bundles 1st edition Read Online Active 1 month ago. Elementary Arithmetic by Charles W. Choose a problem to solve from the problem list, work the Modular representations and elementary abelian groups; 2. Sign up using Email and Password. Theory 12 , Fuchs What are, if any, subgroups in between? Commutative group in which all nonzero elements have the same order. He has authored a number of books, including Representations and Cohomology Cambridge, and Polynomial Invariants of Finite Groups Cambridge, With no similar books on the market, this will be an invaluable resource for graduate students and researchers working in representation theory. In Anna Maria Elementary moved into the new building, and most old buildings were Ask Question. This article may require cleanup to meet Wikipedia's quality standards. Papers, preprints and other things. Boundaries Of Contagion: How PDF file. This class is closed under taking direct sums, tensor products, duals, Heller shifts and direct summands, and includes endotrivial modules. We start with the finite generation of cohomology of a finite group scheme and proceed to discuss various consequences and theories that ultimately grew out of that result. This book is a historic document, showing the buildings before Privacy policy About Groupprops Disclaimers Mobile view. This collection of literature attempts to compile many of the classic, timeless works that have stood the test of time and offer them at a reduced, affordable price, in an attractive volume so that everyone can enjoy them. Courier Corporation. Conversely, to check whether a given group is in fact the group we want, we can use GAP's IdGroup function:. Linear algebraic group Reductive group Abelian variety Elliptic curve. It follows that G has a nontrivial center , which is necessarily invariant under all automorphisms, and thus equals all of G. The material is mostly complementary to the article of D. Abstract: This is a survey article covering developments in representation theory of finite group schemes over the last fifteen years. Benson , Trans. Buy As Gift. Presently, in the rest of this article, these groups are assumed finite. The extra special groups are extensions of elementary abelian groups by a cyclic group of order p, and are analogous to the Heisenberg group. If you read carefully, I used the word "analogous", not generalization Building upon this result, we introduce the support cone of such a module, extending the construction of support variety for a finite dimensional module, and show that such support cones satisfy most of the familiar properties of support varieties.
Recommended publications
  • REPRESENTATIONS of ELEMENTARY ABELIAN P-GROUPS and BUNDLES on GRASSMANNIANS
    REPRESENTATIONS OF ELEMENTARY ABELIAN p-GROUPS AND BUNDLES ON GRASSMANNIANS JON F. CARLSON∗, ERIC M. FRIEDLANDER∗∗ AND JULIA PEVTSOVA∗∗∗ Abstract. We initiate the study of representations of elementary abelian p- groups via restrictions to truncated polynomial subalgebras of the group alge- p p bra generated by r nilpotent elements, k[t1; : : : ; tr]=(t1; : : : ; tr ). We introduce new geometric invariants based on the behavior of modules upon restrictions to such subalgebras. We also introduce modules of constant radical and socle type generalizing modules of constant Jordan type and provide several gen- eral constructions of modules with these properties. We show that modules of constant radical and socle type lead to families of algebraic vector bundles on Grassmannians and illustrate our theory with numerous examples. Contents 1. The r-rank variety Grass(r; V)M 4 2. Radicals and Socles 10 3. Modules of constant radical and socle rank 15 4. Modules from quantum complete intersections 20 5. Radicals of Lζ -modules 27 6. Construction of Bundles on Grass(r; V) 35 6.1. A local construction of bundles 36 6.2. A construction by equivariant descent 38 7. Bundles for GLn-equivariant modules. 43 8. A construction using the Pl¨ucker embedding 51 9. APPENDIX (by J. Carlson). Computing nonminimal 2-socle support varieties using MAGMA 57 References 59 Quillen's fundamental ideas on applying geometry to the study of group coho- mology in positive characteristic [Quillen71] opened the door to many exciting de- velopments in both cohomology and modular representation theory. Cyclic shifted subgroups, the prototypes of the rank r shifted subgroups studied in this paper, were introduced by Dade in [Dade78] and quickly became the subject of an intense study.
    [Show full text]
  • Fusion Systems and Group Actions with Abelian Isotropy Subgroups
    FUSION SYSTEMS AND GROUP ACTIONS WITH ABELIAN ISOTROPY SUBGROUPS OZG¨ UN¨ UNL¨ U¨ AND ERGUN¨ YALC¸IN Abstract. We prove that if a finite group G acts smoothly on a manifold M so that all the isotropy subgroups are abelian groups with rank ≤ k, then G acts freely and smoothly n1 n on M × S × · · · × S k for some positive integers n1; : : : ; nk. We construct these actions using a recursive method, introduced in an earlier paper, that involves abstract fusion systems on finite groups. As another application of this method, we prove that every finite solvable group acts freely and smoothly on some product of spheres with trivial action on homology. 1. Introduction and statement of results Madsen-Thomas-Wall [7] proved that a finite group G acts freely on a sphere if (i) G has no subgroup isomorphic to the elementary abelian group Z=p × Z=p for any prime number p and (ii) has no subgroup isomorphic to the dihedral group D2p of order 2p for any odd prime number p. At that time the necessity of these conditions were already known: P. A. Smith [12] proved that the condition (i) is necessary and Milnor [8] showed the necessity of the condition (ii). As a generalization of the above problem we are interested in the problem of character- izing those finite groups which can act freely and smoothly on a product of k spheres for a given positive integer k. In the case k = 1, Madsen-Thomas-Wall uses surgery theory and considers the unit spheres of linear representations of subgroups to show that certain surgery obstructions vanish.
    [Show full text]
  • Finite Group Actions on the Four-Dimensional Sphere Finite Group Actions on the Four-Dimensional Sphere
    Finite Group Actions on the Four-Dimensional Sphere Finite Group Actions on the Four-Dimensional Sphere By Sacha Breton, B.Sc. A Thesis Submitted to the School of Graduate Studies in Partial Fulfilment of the Requirements for the Degree of Master of Science McMaster University c Copyright by Sacha Breton, August 30th 2011 Master of Science (2011) McMaster University Hamilton, Ontario Department of Mathematics and Statistics TITLE: Finite Group Actions on the Four-Dimensional Sphere AUTHOR: Sacha Breton B.Sc. (McGill University) SUPERVISOR: Ian Hambleton NUMBER OF PAGES: 41 + v ii Abstract Smith theory provides powerful tools for understanding the geometry of singular sets of group actions on spheres. In this thesis, tools from Smith theory and spectral sequences are brought together to study the singular sets of elementary abelian groups acting locally linearly on S4. It is shown that the singular sets of such actions are homeomorphic to the singular sets of linear actions. A short review of the literature on group actions on S4 is included. iii Acknowledgements I would like to thank Professor Ian Hambleton for his suggestion of thesis topic, for the breadth and depth of his advice, and for his patience and encouragement. I would also like to thank Val´erieTremblay, Barnaby and Sue Ore, my parents, and my friends for their continued support. iv Contents Descriptive Note ii Abstract iii Acknowledgements iv 1 Introduction 1 2 Introductory Material 1 2.1 Basic definitions and conventions . .1 2.2 The Projection and the Transfer homomorphisms . .4 2.3 Smith Theory . .7 2.4 Group cohomology .
    [Show full text]
  • ELEMENTARY ABELIAN P-SUBGROUPS of ALGEBRAIC GROUPS
    ROBERT L. GRIESS, JR ELEMENTARY ABELIAN p-SUBGROUPS OF ALGEBRAIC GROUPS Dedicated to Jacques Tits for his sixtieth birthday ABSTRACT. Let ~ be an algebraically closed field and let G be a finite-dimensional algebraic group over N which is nearly simple, i.e. the connected component of the identity G O is perfect, C6(G °) = Z(G °) and G°/Z(G °) is simple. We classify maximal elementary abelian p-subgroups of G which consist of semisimple elements, i.e. for all primes p ~ char K. Call a group quasisimple if it is perfect and is simple modulo the center. Call a subset of an algebraic group total if it is in a toms; otherwise nontoral. For several quasisimple algebraic groups and p = 2, we define complexity, and give local criteria for whether an elementary abelian 2-subgroup of G is total. For all primes, we analyze the nontoral examples, include a classification of all the maximal elementary abelian p-groups, many of the nonmaximal ones, discuss their normalizers and fusion (i.e. how conjugacy classes of the ambient algebraic group meet the subgroup). For some cases, we give a very detailed discussion, e.g. p = 3 and G of type E6, E 7 and E 8. We explain how the presence of spin up and spin down elements influences the structure of projectively elementary abelian 2-groups in Spin(2n, C). Examples of an elementary abelian group which is nontoral in one algebraic group but toral in a larger one are noted. Two subsets of a maximal torus are conjugate in G iff they are conjugate in the normalizer of the torus; this observation, with our discussion of the nontoral cases, gives a detailed guide to the possibilities for the embedding of an elementary abelian p-group in G.
    [Show full text]
  • Arxiv:1310.6548V1 [Math.GR] 24 Oct 2013 Every Hwta H Iuto O Ocmatmnflsi Ut Di Quite Is 3
    FINITE SUBGROUPS OF DIFFEOMORPHISM GROUPS ∗ VLADIMIR L. POPOV Abstract. We prove (1) the existence of a noncompact smooth four-di- mensional manifold M such that Diff(M) contains an isomorphic copy of every finitely presented group; (2) a finiteness theorem on finite simple subgroups of Diff(N) for compact manifolds N. 1. In [Po10, Sect. 2] was introduced the definition of abstract Jordan group and initiated exploration of the following two problems on automorphism groups and birational self-map groups of algebraic varieties: Problem A. Describe algebraic varieties X for which Aut(X) is Jordan. Problem B. The same with Aut(X) replaced by Bir(X). Recall from [Po10, Def. 2.1] that Jordaness of a group is defined as follows: Definition 1. A group G is called a Jordan group if there exists a positive integer dG, depending on G only, such that every finite subgroup F of G contains a normal abelian subgroup whose index in F is at most dG. Informally Jordaness means that all finite subgroups of G are “almost” abelian in the sense that they are extensions of abelian groups by finite groups taken from a finite list. Since the time of launching the exploration program of Problems A and B a rather extensive information on them has been obtained (see [Po132]), but, for instance, at this writing (October 2013) is still unknown whether there exists X with non-Jordan group Aut(X) (see Question 1 in [Po132]; it is interesting to juxtapose it with Corollary 2 below). 2. In this note we explore the counterpart of Problem A, in which algebraic varieties X are replaced by connected smooth topological manifolds M, and arXiv:1310.6548v1 [math.GR] 24 Oct 2013 Aut(X) is replaced by Diff(M), the diffeomorphism group of M.
    [Show full text]
  • The Theory of Finite Groups: an Introduction (Universitext)
    Universitext Editorial Board (North America): S. Axler F.W. Gehring K.A. Ribet Springer New York Berlin Heidelberg Hong Kong London Milan Paris Tokyo This page intentionally left blank Hans Kurzweil Bernd Stellmacher The Theory of Finite Groups An Introduction Hans Kurzweil Bernd Stellmacher Institute of Mathematics Mathematiches Seminar Kiel University of Erlangen-Nuremburg Christian-Albrechts-Universität 1 Bismarckstrasse 1 /2 Ludewig-Meyn Strasse 4 Erlangen 91054 Kiel D-24098 Germany Germany [email protected] [email protected] Editorial Board (North America): S. Axler F.W. Gehring Mathematics Department Mathematics Department San Francisco State University East Hall San Francisco, CA 94132 University of Michigan USA Ann Arbor, MI 48109-1109 [email protected] USA [email protected] K.A. Ribet Mathematics Department University of California, Berkeley Berkeley, CA 94720-3840 USA [email protected] Mathematics Subject Classification (2000): 20-01, 20DXX Library of Congress Cataloging-in-Publication Data Kurzweil, Hans, 1942– The theory of finite groups: an introduction / Hans Kurzweil, Bernd Stellmacher. p. cm. — (Universitext) Includes bibliographical references and index. ISBN 0-387-40510-0 (alk. paper) 1. Finite groups. I. Stellmacher, B. (Bernd) II. Title. QA177.K87 2004 512´.2—dc21 2003054313 ISBN 0-387-40510-0 Printed on acid-free paper. © 2004 Springer-Verlag New York, Inc. All rights reserved. This work may not be translated or copied in whole or in part without the written permission of the publisher (Springer-Verlag New York, Inc., 175 Fifth Avenue, New York, NY 10010, USA), except for brief excerpts in connection with reviews or scholarly analysis.
    [Show full text]
  • Kernels of Linear Representations of Lie Groups, Locally Compact
    Kernels of Linear Representations of Lie Groups, Locally Compact Groups, and Pro-Lie Groups Markus Stroppel Abstract For a topological group G the intersection KOR(G) of all kernels of ordinary rep- resentations is studied. We show that KOR(G) is contained in the center of G if G is a connected pro-Lie group. The class KOR(C) is determined explicitly if C is the class CONNLIE of connected Lie groups or the class ALMCONNLIE of almost con- nected Lie groups: in both cases, it consists of all compactly generated abelian Lie groups. Every compact abelian group and every connected abelian pro-Lie group occurs as KOR(G) for some connected pro-Lie group G. However, the dimension of KOR(G) is bounded by the cardinality of the continuum if G is locally compact and connected. Examples are given to show that KOR(C) becomes complicated if C contains groups with infinitely many connected components. 1 The questions we consider and the answers that we have found In the present paper we study (Hausdorff) topological groups. Ifall else fails, we endow a group with the discrete topology. For any group G one tries, traditionally, to understand the group by means of rep- resentations as groups of matrices. To this end, one studies the continuous homomor- phisms from G to GLnC for suitable positive integers n; so-called ordinary representa- tions. This approach works perfectly for finite groups because any such group has a faithful ordinary representation but we may face difficulties for infinite groups; there do exist groups admitting no ordinary representations apart from the trivial (constant) one.
    [Show full text]
  • Notes on Finite Group Theory
    Notes on finite group theory Peter J. Cameron October 2013 2 Preface Group theory is a central part of modern mathematics. Its origins lie in geome- try (where groups describe in a very detailed way the symmetries of geometric objects) and in the theory of polynomial equations (developed by Galois, who showed how to associate a finite group with any polynomial equation in such a way that the structure of the group encodes information about the process of solv- ing the equation). These notes are based on a Masters course I gave at Queen Mary, University of London. Of the two lecturers who preceded me, one had concentrated on finite soluble groups, the other on finite simple groups; I have tried to steer a middle course, while keeping finite groups as the focus. The notes do not in any sense form a textbook, even on finite group theory. Finite group theory has been enormously changed in the last few decades by the immense Classification of Finite Simple Groups. The most important structure theorem for finite groups is the Jordan–Holder¨ Theorem, which shows that any finite group is built up from finite simple groups. If the finite simple groups are the building blocks of finite group theory, then extension theory is the mortar that holds them together, so I have covered both of these topics in some detail: examples of simple groups are given (alternating groups and projective special linear groups), and extension theory (via factor sets) is developed for extensions of abelian groups. In a Masters course, it is not possible to assume that all the students have reached any given level of proficiency at group theory.
    [Show full text]
  • Cyclotomy and Difference Families in Elementary Abelian Groups*
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector JOURNAL OF NUMBER THEORY 4, 17-47 (1972) Cyclotomy and Difference Families in Elementary Abelian Groups* RICHARD M. WILSON+ Department of Mathematics, Ohio State University, Columbus, Ohio 43210 Communicated by A. C. Woods Received May 1, 1970 By a (v, k, h)-difference family in an additive abelian group G of order v, we mean a family (4 j i E Z) of subsets of G, each of cardinality k, and such that among the differences (a - b / q b E Z3<; a # b; i E Z) each nonzero g E G occurs X times. The existence of such a difference family implies the existence of a (v, k, X)-BIBD with G as a regular group of automorphisms. The multiplicative structure of finite fields is used here to construct difference families in their additive groups. It is proven that if q is a prime power and q > {ik(k - l)}klk-l), then there exists a (q, k, h)-difference family in the elementary abelian group of order q iff X(q - 1) = 0 (mod k(k - 1)). Some extensions of known con- structions and partially balanced designs are also discussed. 1. BALANCED INCOMPLETE BLOCK DESIGNS An incidence structure is a triple (P, L, 9) where P is a set of points, L is a set of lines, and Y is an incidence relation between P and L which we view as a mapping from P x L into the set of integers (0, I}.
    [Show full text]
  • Finite Simple Groups Which Projectively Embed in an Exceptional Lie Group Are Classified!
    BULLETIN (New Series) OF THE AMERICAN MATHEMATICAL SOCIETY Volume 36, Number 1, January 1999, Pages 75{93 S 0273-0979(99)00771-5 FINITE SIMPLE GROUPS WHICH PROJECTIVELY EMBED IN AN EXCEPTIONAL LIE GROUP ARE CLASSIFIED! ROBERT L. GRIESS JR. AND A. J. E. RYBA Abstract. Since finite simple groups are the building blocks of finite groups, it is natural to ask about their occurrence “in nature”. In this article, we consider their occurrence in algebraic groups and moreover discuss the general theory of finite subgroups of algebraic groups. 0. Introduction Group character theory classifies embeddings of finite groups into classical groups. No general theory classifies embeddings into the exceptional complex al- gebraic group, i.e., one of G2(C), F4(C), E6(C), E7(C), E8(C). For exceptional groups, special methods seem necessary. Since the early 80s, there have been ef- forts to determine which central extensions of finite simple groups embed in an exceptional group. For short, we call this work a study of projective embeddings of finite simple groups into exceptional groups. Table PE on page 84 contains a summary. The classification program for finite subgroups of complex algebraic groups involves both existence of embeddings and their classification up to conjugacy. We have just classified embeddings of Sz(8) into E8(C) (there are three, up to E8(C)- conjugacy), thus settling the existence question for projective embeddings of finite simple groups into exceptional algebraic groups. The conjugacy part of the program is only partially resolved. The finite subgroups of the smallest simple algebraic group PSL(2; C)(upto conjugacy) constitute the famous list: cyclic, dihedral, Alt4, Sym4, Alt5.
    [Show full text]
  • Quaternionic Root Systems and Subgroups of the $ Aut (F {4}) $
    Quaternionic Root Systems and Subgroups of the Aut(F4) Mehmet Koca∗ and Muataz Al-Barwani† Department of Physics, College of Science, Sultan Qaboos University, PO Box 36, Al-Khod 123, Muscat, Sultanate of Oman Ramazan Ko¸c‡ Department of Physics, Faculty of Engineering University of Gaziantep, 27310 Gaziantep, Turkey (Dated: November 12, 2018) Cayley-Dickson doubling procedure is used to construct the root systems of some celebrated Lie algebras in terms of the integer elements of the division algebras of real numbers, complex numbers, quaternions and octonions. Starting with the roots and weights of SU(2) expressed as the real numbers one can construct the root systems of the Lie algebras of SO(4), SP (2) ≈ SO(5), SO(8), SO(9), F4 and E8 in terms of the discrete elements of the division algebras. The roots themselves display the group structures besides the octonionic roots of E8 which form a closed octonion algebra. The automorphism group Aut(F4) of the Dynkin diagram of F4 of order 2304, the largest crystallographic group in 4-dimensional Euclidean space, is realized as the direct product of two binary octahedral group of quaternions preserving the quaternionic root system of F4 .The Weyl groups of many Lie algebras, such as, G2, SO(7), SO(8), SO(9), SU(3)XSU(3) and SP (3) × SU(2) have been constructed as the subgroups of Aut(F4) .We have also classified the other non-parabolic subgroups of Aut(F4) which are not Weyl groups. Two subgroups of orders192 with different conju- gacy classes occur as maximal subgroups in the finite subgroups of the Lie group G2 of orders 12096 and 1344 and proves to be useful in their constructions.
    [Show full text]
  • 7. Minimal Normal Subgroups and the Socle Throughout This Section G Is A
    34 NICK GILL 7. Minimal normal subgroups and the socle Throughout this sectionG is a nontrivial group. A minimal normal subgroup ofG is a normal subgroup K= 1 ofG which does not contain any other nontrivial normal subgroup ofG. The socle, soc(G) is the subgroup� generated by the set of all minimal normal subgroups (ifG has no minimal normal subgroups, then we set soc(G) = 1). (E7.1)Find the socle ofD 10,A 4,S 4,S 4 Z. × (E7.2)Give an example of a group that has no minimal normal subgroup. (E7.3)IfG is the direct product of a (possibly infinite) number of finite simple groups, then what is soc(G)? (E7.4)Give a characteri ation of almost simple groups in terms of their socle. Clearly soc(G) is a characteristic subgroup ofG. 26 Theorem 7.1. LetG be a nontrivial finite group. (1) IfK is a minimal normal subgroup ofG, andL is any normal subgroup ofG, then eitherK L or K,L =K L. 27 ≤ (2) There� exist� minimal× normal subgroupsK ,...,K ofG such that soc(G)=K K . 1 m 1 × · · · m (3) Every minimal normal subgroupK ofG is a direct productK=T 1 T k where theT i are simple normal subgroups ofK which are conjugate inG. × · · · (4) If the subgroupsK i in (2) are all nonabelian, thenK 1,...,Km are the only minimal normal sub- groups ofG. Proof. (1) #inceK L�G, the minimality ofK implies that eitherK L orK L= 1 . $n the latter case, since∩ K andL are both normal, we have that K,L =≤KL=K∩L.
    [Show full text]