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Questions about the branch of algebra that deals with groups.

-1 votes

Is Higman's group a free product?

The abelianization of the Higman group $G$ is trivial, because in the presence of commutativity the relations become $a = 1$, $b =1$, $c =1$, $d=1$. Therefore $G$ is not free.
Jeff Strom's user avatar
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4 votes

The Higman group

Reference: Higman, Graham, A finitely generated infinite simple group, J. Lond. Math. Soc. 26, 61-64 (1951). ZBL0042.02201. It is shown that $G$ is infinite and has no proper normal subgroups of fini …
Jeff Strom's user avatar
  • 12.5k
5 votes
1 answer
770 views

Groups with no perfect subgroups -- terminology?

Finite groups are solvable if they have no nontrivial perfect subgroup. But I am sure that for infinite groups, the two notions diverge. Is there standard terminology for groups with no perfect sub …
Jeff Strom's user avatar
  • 12.5k
5 votes
1 answer
179 views

The stabilizer of the conditionally convergent series

The standard rearrangement theorem for conditionally convergent series says that the terms in a conditionally convergent series can be rearranged so that the new sum is any desired number, or $\pm\inf …
Jeff Strom's user avatar
  • 12.5k
2 votes
0 answers
72 views

Terminology and notation for generated subgroups

I would like to think about formation of the smallest subgroup (or monoid, or whatever) $H$ of $G$ containing two given subgroups $A$ and $B$ as an operation on subgroups, and I wonder if there is a …
Jeff Strom's user avatar
  • 12.5k