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Questions about the branch of algebra that deals with groups.

14 votes

Quotient of a Hausdorff topological group by a closed subgroup

In fact, an even stronger statement holds: If $G$ is a topological group and $H$ is an (abstract) subgroup, then $G/H$ is Hausdorff if and only if $H$ is closed (cf Bourbaki, General Topology, III.2.5 …
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8 votes
2 answers
1k views

(Non-trivial) presentation of general linear and symplectic group over Z/mZ?

I know that there exists a nice presentation (generators and relations) of the general linear group over a finite field (by Steinberg, I think). Is there also a nice presentation of $GL(n,\mathbb{Z}/m …
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6 votes
2 answers
2k views

Classification of finite complex reflection groups

Background: Let $K$ be a field and let $V$ be a finite-dimensional $K$-vector space. A pseudoreflection (or usually imprecisely just reflection) in $V$ is an element $1 \neq s \in \mathrm{GL}(V)$ fix …
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3 votes
2 answers
688 views

Automorphisms of the totally ordered group $\mathbb{Z}{^n}$ with lexicographical order

It is easy to see that the totally ordered group $\mathbb{Z}$ (the integers) with the natural order has no non-trivial automorphisms. Is this also true for $\mathbb{Z}^n$ with the lexicographical orde …
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