Talk:Outer automorphism group

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[edit] Simple groups of Lie type

What is the precise structures of Outer automorphism groups of Lie type simple groups? —Preceding unsigned comment added by 219.138.209.67 (talk • contribs)

[edit] Integers

Tha table says that Out(Z) = Z_2, but all the definitions lead to Out(Z) = Z. In fact, Inn(Z) = 0, since Z is abelian. Which is the reference used for the table? Espigaymostaza (talk) 14:40, 11 June 2008 (UTC)

Aut(Z) = Units(Z) = {+1,-1} is cyclic of order two. Hence Out(Z) = Aut(Z)/Inn(Z) =~ Aut(Z) is cyclic of order two. The table is likely pulled from several references. The cleanup tag "fact" has been added to indicate someone should go and record which references. JackSchmidt (talk) 15:03, 11 June 2008 (UTC)