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From: Tonico on 5 Oct 2006 15:36 mareg(a)mimosa.csv.warwick.ac.uk wrote: > In article <1160046334.164177.156020(a)m73g2000cwd.googlegroups.com>, > "Tonico" <Tonicopm(a)yahoo.com> writes: > > > >mareg(a)mimosa.csv.warwick.ac.uk wrote: > >> In article <19790289.1159493051233.JavaMail.jakarta(a)nitrogen.mathforum.org>, > >> Cezanne123 <Cezanne123(a)aol.com> writes: > >> >Let G be a group such that the intersection of all its subgroups which are different from (e) is a subgroup different from (e). Prove that every element in G has finite order. > >> > > >> >How do you show this is true? > >> > >> Well the property that you mention is false in the infinite cyclic group, so > >> it is also false in any group that contains an element of infinite order. > >> > >> Derek Holt. > >********************************************************************************* > >Perhaps I missed something here: the intersection of all the > >non-trivial sbgps of the infinite cyclic group (Z ) is zero, otherwise > >there'd be an integer divisible by > >ANY prime... > >So the OP's condition on the group isn't applicable to Z. > > That's exactly what I said above! I was trying to give hint rather than a > detailed proof. > > Derek Holt. ********************************************* Damn, so you did! Sorry, I completely misunderstood your post, Derek. After you wrote the explanation I thought otherwise. Indeed it was pretty elementary. Regards Tonio |