Applying the Classification of Finite Simple Groups a User’S Guide
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Higher Algebraic K-Theory I
1 Higher algebraic ~theory: I , * ,; Daniel Quillen , ;,'. ··The·purpose of..thispaper.. is.to..... develop.a.higher. X..,theory. fpJ;' EiddUiy!!. categQtl~ ... __ with euct sequences which extends the ell:isting theory of ths Grothsndieck group in a natural wll7. To describe' the approach taken here, let 10\ be an additive category = embedded as a full SUbcategory of an abelian category A, and assume M is closed under , = = extensions in A. Then one can form a new category Q(M) having the same objects as ')0\ , = =, = but :in which a morphism from 101 ' to 10\ is taken to be an isomorphism of MI with a subquotient M,IM of M, where MoC 101, are aubobjects of M such that 101 and MlM, o 0 are objects of ~. Assuming 'the isomorphism classes of objects of ~ form a set, the, cstegory Q(M)= has a classifying space llQ(M)= determined up to homotopy equivalence. One can show that the fundamental group of this classifying spacs is canonically isomor- phic to the Grothendieck group of ~ which motivates dsfining a ssquenoe of X-groups by the formula It is ths goal of the present paper to show that this definition leads to an interesting theory. The first part pf the paper is concerned with the general theory of these X-groups. Section 1 contains various tools for working .~th the classifying specs of a small category. It concludes ~~th an important result which identifies ·the homotopy-theoretic fibre of the map of classifying spaces induced by a.functor. In X-theory this is used to obtain long exsct sequences of X-groups from the exact homotopy sequence of a map. -
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. -
September 2014
LONDONLONDON MATHEMATICALMATHEMATICAL SOCIETYSOCIETY NEWSLETTER No. 439 September 2014 Society Meetings HIGHEST HONOUR FOR UK and Events MATHEMATICAN Professor Martin Hairer, FRS, 2014 University of Warwick, has become the ninth UK based Saturday mathematician to win the 6 September prestigious Fields Medal over Mathematics and the its 80 year history. The medal First World War recipients were announced Meeting, London on Wednesday 13 August in page 15 a ceremony at the four-year- ly International Congress for 1 Wednesday Mathematicians, which on this 24 September occasion was held in Seoul, South Korea. LMS Popular Lectures See page 4 for the full report. Birmingham page 12 Friday LMS ANNOUNCES SIMON TAVARÉ 14 November AS PRESIDENT-DESIGNATE LMS AGM © The University of Cambridge take over from the London current President, Professor Terry Wednesday Lyons, FRS, in 17 December November 2015. SW & South Wales Professor Tavaré is Meeting a versatile math- Plymouth ematician who has established a distinguished in- ternational career culminating in his current role as The London Mathematical Director of the Cancer Research Society is pleased to announce UK Cambridge Institute and Professor Simon Tavaré, Professor in DAMTP, where he NEWSLETTER FRS, FMedSci, University of brings his understanding of sto- ONLINE: Cambridge, as President-Des- chastic processes and expertise newsletter.lms.ac.uk ignate. Professor Tavaré will in the data science of DNA se- (Cont'd on page 3) LMS NEWSLETTER http://newsletter.lms.ac.uk Contents No. 439 September 2014 15 44 Awards Partial Differential Equations..........................37 Collingwood Memorial Prize..........................11 Valediction to Jeremy Gray..............................33 Calendar of Events.......................................50 News LMS Items European News.................................................16 HEA STEM Strategic Project........................... -
An Invitation to Toric Topology: Vertex Four of a Remarkable Tetrahedron
An Invitation to Toric Topology: Vertex Four of a Remarkable Tetrahedron. Buchstaber, Victor M and Ray, Nigel 2008 MIMS EPrint: 2008.31 Manchester Institute for Mathematical Sciences School of Mathematics The University of Manchester Reports available from: http://eprints.maths.manchester.ac.uk/ And by contacting: The MIMS Secretary School of Mathematics The University of Manchester Manchester, M13 9PL, UK ISSN 1749-9097 Contemporary Mathematics An Invitation to Toric Topology: Vertex Four of a Remarkable Tetrahedron Victor M Buchstaber and Nigel Ray 1. An Invitation Motivation. Sometime around the turn of the recent millennium, those of us in Manchester and Moscow who had been collaborating since the mid-1990s began using the term toric topology to describe our widening interests in certain well-behaved actions of the torus. Little did we realise that, within seven years, a significant international conference would be planned with the subject as its theme, and delightful Japanese hospitality at its heart. When first asked to prepare this article, we fantasised about an authorita- tive and comprehensive survey; one that would lead readers carefully through the foothills above which the subject rises, and provide techniques for gaining sufficient height to glimpse its extensive mathematical vistas. All this, and more, would be illuminated by references to the wonderful Osaka lectures! Soon afterwards, however, reality took hold, and we began to appreciate that such a task could not be completed to our satisfaction within the timescale avail- able. Simultaneously, we understood that at least as valuable a service could be rendered to conference participants by an invitation to a wider mathematical au- dience - an invitation to savour the atmosphere and texture of the subject, to consider its geology and history in terms of selected examples and representative literature, to glimpse its exciting future through ongoing projects; and perhaps to locate favourite Osaka lectures within a novel conceptual framework. -
17 Oct 2019 Sir Michael Atiyah, a Knight Mathematician
Sir Michael Atiyah, a Knight Mathematician A tribute to Michael Atiyah, an inspiration and a friend∗ Alain Connes and Joseph Kouneiher Sir Michael Atiyah was considered one of the world’s foremost mathematicians. He is best known for his work in algebraic topology and the codevelopment of a branch of mathematics called topological K-theory together with the Atiyah-Singer index theorem for which he received Fields Medal (1966). He also received the Abel Prize (2004) along with Isadore M. Singer for their discovery and proof of the index the- orem, bringing together topology, geometry and analysis, and for their outstanding role in building new bridges between mathematics and theoretical physics. Indeed, his work has helped theoretical physicists to advance their understanding of quantum field theory and general relativity. Michael’s approach to mathematics was based primarily on the idea of finding new horizons and opening up new perspectives. Even if the idea was not validated by the mathematical criterion of proof at the beginning, “the idea would become rigorous in due course, as happened in the past when Riemann used analytic continuation to justify Euler’s brilliant theorems.” For him an idea was justified by the new links between different problems which it illuminated. Our experience with him is that, in the manner of an explorer, he adapted to the landscape he encountered on the way until he conceived a global vision of the setting of the problem. Atiyah describes here 1 his way of doing mathematics2 : arXiv:1910.07851v1 [math.HO] 17 Oct 2019 Some people may sit back and say, I want to solve this problem and they sit down and say, “How do I solve this problem?” I don’t. -
Arxiv:1305.5974V1 [Math-Ph]
INTRODUCTION TO SPORADIC GROUPS for physicists Luis J. Boya∗ Departamento de F´ısica Te´orica Universidad de Zaragoza E-50009 Zaragoza, SPAIN MSC: 20D08, 20D05, 11F22 PACS numbers: 02.20.a, 02.20.Bb, 11.24.Yb Key words: Finite simple groups, sporadic groups, the Monster group. Juan SANCHO GUIMERA´ In Memoriam Abstract We describe the collection of finite simple groups, with a view on physical applications. We recall first the prime cyclic groups Zp, and the alternating groups Altn>4. After a quick revision of finite fields Fq, q = pf , with p prime, we consider the 16 families of finite simple groups of Lie type. There are also 26 extra “sporadic” groups, which gather in three interconnected “generations” (with 5+7+8 groups) plus the Pariah groups (6). We point out a couple of physical applications, in- cluding constructing the biggest sporadic group, the “Monster” group, with close to 1054 elements from arguments of physics, and also the relation of some Mathieu groups with compactification in string and M-theory. ∗[email protected] arXiv:1305.5974v1 [math-ph] 25 May 2013 1 Contents 1 Introduction 3 1.1 Generaldescriptionofthework . 3 1.2 Initialmathematics............................ 7 2 Generalities about groups 14 2.1 Elementarynotions............................ 14 2.2 Theframeworkorbox .......................... 16 2.3 Subgroups................................. 18 2.4 Morphisms ................................ 22 2.5 Extensions................................. 23 2.6 Familiesoffinitegroups ......................... 24 2.7 Abeliangroups .............................. 27 2.8 Symmetricgroup ............................. 28 3 More advanced group theory 30 3.1 Groupsoperationginspaces. 30 3.2 Representations.............................. 32 3.3 Characters.Fourierseries . 35 3.4 Homological algebra and extension theory . 37 3.5 Groupsuptoorder16.......................... -
Construction of the Rudvalis Group of Order 145,926,144,000*
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector JOURNAL OF ALGEBRA 27, 538-548 (1973) Construction of the Rudvalis Group of Order 145,926,144,000* J. H. CONWAY Department of Pure Mathematics and Mathematical Statistics, Cambridge, England AND D. B. WALES Department of Mathematics, California Institute of Technology, Pasadena, California 91109 Communicated by Marshall Hall, Jr. Received August 4, 1972 Recently, Arunas Rudvalis [l] provided evidence for the existence of a new simple group R of order 145,926,144,000 = 2r4 * 33 * 5a . 7 * 13 . 29. He describes the group as a rank 3 permutation group on 4060 letters, in which the stabilizer of a point is the (nonsimple) Ree group F = V’,(2), which has orbits of sizes 1,1755,2304, corresponding to subgroups of F of orders 20480 and 15600. The first of these is the centralizer of an involution of F, while the second has the known subgroup L = PSLa(25) of P’ (see Ref. [4]) as a subgroup of index 2. Since one of the involutions in R has no fixed point and so just 2030 2-cycles, an argument of Griess and Schur [2] shows that R has a proper double cover 2R. Rudvalis and Frame gave evidence for supposing that this group had a 28-dimensional complex representation not splitting over F. (Feit and Lyons have proved this under further assumptions on R.) We sup- pose that this unitary representation of 2R exists while constructing the group, but then conclude independently of this supposition that the con- struction defines a group 2R whose central quotient is R. -
Calculus Redux
THE NEWSLETTER OF THE MATHEMATICAL ASSOCIATION OF AMERICA VOLUME 6 NUMBER 2 MARCH-APRIL 1986 Calculus Redux Paul Zorn hould calculus be taught differently? Can it? Common labus to match, little or no feedback on regular assignments, wisdom says "no"-which topics are taught, and when, and worst of all, a rich and powerful subject reduced to Sare dictated by the logic of the subject and by client mechanical drills. departments. The surprising answer from a four-day Sloan Client department's demands are sometimes blamed for Foundation-sponsored conference on calculus instruction, calculus's overcrowded and rigid syllabus. The conference's chaired by Ronald Douglas, SUNY at Stony Brook, is that first surprise was a general agreement that there is room for significant change is possible, desirable, and necessary. change. What is needed, for further mathematics as well as Meeting at Tulane University in New Orleans in January, a for client disciplines, is a deep and sure understanding of diverse and sometimes contentious group of twenty-five fac the central ideas and uses of calculus. Mac Van Valkenberg, ulty, university and foundation administrators, and scientists Dean of Engineering at the University of Illinois, James Ste from client departments, put aside their differences to call venson, a physicist from Georgia Tech, and Robert van der for a leaner, livelier, more contemporary course, more sharply Vaart, in biomathematics at North Carolina State, all stressed focused on calculus's central ideas and on its role as the that while their departments want to be consulted, they are language of science. less concerned that all the standard topics be covered than That calculus instruction was found to be ailing came as that students learn to use concepts to attack problems in a no surprise. -
Quillen's Work in Algebraic K-Theory
J. K-Theory 11 (2013), 527–547 ©2013 ISOPP doi:10.1017/is012011011jkt203 Quillen’s work in algebraic K-theory by DANIEL R. GRAYSON Abstract We survey the genesis and development of higher algebraic K-theory by Daniel Quillen. Key Words: higher algebraic K-theory, Quillen. Mathematics Subject Classification 2010: 19D99. Introduction This paper1 is dedicated to the memory of Daniel Quillen. In it, we examine his brilliant discovery of higher algebraic K-theory, including its roots in and genesis from topological K-theory and ideas connected with the proof of the Adams conjecture, and his development of the field into a complete theory in just a few short years. We provide a few references to further developments, including motivic cohomology. Quillen’s main work on algebraic K-theory appears in the following papers: [65, 59, 62, 60, 61, 63, 55, 57, 64]. There are also the papers [34, 36], which are presentations of Quillen’s results based on hand-written notes of his and on communications with him, with perhaps one simplification and several inaccuracies added by the author. Further details of the plus-construction, presented briefly in [57], appear in [7, pp. 84–88] and in [77]. Quillen’s work on Adams operations in higher algebraic K-theory is exposed by Hiller in [45, sections 1-5]. Useful surveys of K-theory and related topics include [81, 46, 38, 39, 67] and any chapter in Handbook of K-theory [27]. I thank Dale Husemoller, Friedhelm Waldhausen, Chuck Weibel, and Lars Hesselholt for useful background information and advice. 1. -
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. -
On the O'nan-Scott Theorem for Finite Primitive Permutation Groups
J. Austral. Math. Soc. (Series A) 44 (1988), 389-396 ON THE O'NAN-SCOTT THEOREM FOR FINITE PRIMITIVE PERMUTATION GROUPS MARTIN W. LIEBECK, CHERYL E. PRAEGER and JAN SAXL (Received 30 August 1985; revised 2 October 1986) Communicated by H. Lausch Abstract We give a self-contained proof of the O'Nan-Scott Theorem for finite primitive permutation groups. 1980 Mathematics subject classification (Amer. Math. Soc): 20 B 05. Introduction The classification of finite simple groups has led to the solution of many prob- lems in the theory of finite permutation groups. An important starting point in such applications is the reduction theorem for primitive permutation groups first stated by O'Nan and Scott (see [9]). The version particularly useful in this context is that given in Theorem 4.1 of [2]. Unfortunately a case was omitted in the statements in [2, 9] (namely, the case leading to our groups of type III(c) in Section 1 below). A corrected and expanded version of the theorem appears in the long papers [1] and [3]. Our aim here is to update and develop further the material in Section 4 of [2]. We give a self-contained proof of the theorem (stated in Section 2), which extends [2, Theorem 4.1], and which we have found to be in the form most useful for application to permutation groups (see [6] and [8] for example). Most of the ideas of the proof we owe to [1] and [2]. This work was partially supported by ARGS Grant B 84/15502. The authors wish to thank Dr. -
Moonshines for L2(11) and M12
Moonshines for L2(11) and M12 Suresh Govindarajan Department of Physics Indian Institute of Technology Madras (Work done with my student Sutapa Samanta) Talk at the Workshop on Modular Forms and Black Holes @NISER, Bhubaneswar on January 13. 2017 Plan Introduction Some finite group theory Moonshine BKM Lie superalgebras Introduction Classification of Finite Simple Groups Every finite simple group is isomorphic to one of the following groups: (Source: Wikipedia) I A cyclic group with prime order; I An alternating group of degree at least 5; I A simple group of Lie type, including both I the classical Lie groups, namely the groups of projective special linear, unitary, symplectic, or orthogonal transformations over a finite field; I the exceptional and twisted groups of Lie type (including the Tits group which is not strictly a group of Lie type). I The 26 sporadic simple groups. The classification was completed in 2004 when Aschbacher and Smith filled the last gap (`the quasi-thin case') in the proof. Fun Reading: Symmetry and the Monster by Mark Ronan The sporadic simple groups I the Mathieu groups: M11, M12, M22, M23, M24; (found in 1861) I the Janko groups: J1, J2, J3, J4; (others 1965-1980) I the Conway groups; Co1, Co2, Co3; 0 I the Fischer groups; Fi22. Fi23, Fi24; I the Higman-Sims group; HS I the McLaughlin group: McL I the Held group: He; I the Rudvalis group Ru; I the Suzuki sporadic group: Suz; 0 I the O'Nan group: O N; I Harada-Norton group: HN; I the Lyons group: Ly; I the Thompson group: Th; I the baby Monster group: B and Sources: Wikipedia and Mark Ronan I the Fischer-Griess Monster group: M Monstrous Moonshine Conjectures I The j-function has the followed q-series: (q = exp(2πiτ)) j(τ)−744 = q−1+[196883+1] q+[21296876+196883+1] q2+··· I McKay observed that 196883 and 21296876 are the dimensions of the two smallest irreps of the Monster group.