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Article #110Re: Complete Groups / S_6
From: John C. Baez
Date: Mon, 28 Sep 1992 23:30
Date: Mon, 28 Sep 1992 23:30
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In article <1992Sep28.201204.13907@tamsun.tamu.edu> rlm7638@tamsun.tamu.edu (Jack McKinney) writes: > A complete group is one that is isomorphic to its group of >Automorphisms. The symmetric group on n elements is complete for >all integers n _except_ 2 and 6. It is also true that the outer >automorphisms of S_6 form one coset to the set of inner automorphisms. >Can someone provide an outer automorphism on S_6 ? (This would >completely specify Aut(S_6), which is isomorphic to S_6 x Z_2) There was a thread on sci.math where we talked about this. There is a nice construction due to Sylvester and Coxeter. It has some cute relationships to the icosahedron. I will send you (and anyone else who wants) what I have about this.
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Newsgroups: sci.math.research Path: arc1-ca.pugleaf.net!sparky!uunet!spool.mu.edu!uwm.edu!ux1.cso.uiuc.edu!news.cso.uiuc.edu!usenet From: "John C. Baez" <jbaez@BOURBAKI.MIT.EDU> Subject: Re: Complete Groups / S_6 References: <1992Sep28.201204.13907@tamsun.tamu.edu> Nntp-Posting-Host: riesz Message-ID: <1992Sep28.233051.19146@galois.mit.edu> Sender: Daniel Grayson <dan@math.uiuc.edu> X-Submissions-To: sci-math-research@uiuc.edu Organization: MIT Department of Mathematics, Cambridge, MA X-Administrivia-To: sci-math-research-request@uiuc.edu Approved: Daniel Grayson <dan@math.uiuc.edu> Date: Mon, 28 Sep 1992 23:30:51 GMT Lines: 14