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 Yearling
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May
2
comment What is the group of automorphisms of $l^{\infty}$?
The automorphism group of $l^\infty(X)$ will depend on what $X$ is. Also, what structure do you require automorphisms to preserve?
Apr
25
revised Characteristically simple locally compact abelian groups
changed to exclude some trivial examples
Apr
25
comment Characteristically simple locally compact abelian groups
Ah yes, I meant to exclude trivial examples like that (e.g. by also requiring $G$ to be locally elliptic). Indeed it is the TCS condition that gives some hope of a classification. It looks like all examples will have a compact open subgroup $U$ isomorphic to $\mathbb{Z}^{\mathbb{N}}_p$ with $G/U$ isomorphic to a direct sum of Prüfer $p$-groups, but there could be many ways of putting $U$ and $G/U$ together.
Apr
23
asked Characteristically simple locally compact abelian groups
Feb
24
reviewed Approve Berry-Esseen bound for martingale sequence with varying and dependent variances
Feb
21
comment Dicks–Dunwoody almost stability theorem
Indeed, the translation is very straightforward in hindsight, but there have been a few papers spelling out the CAT(0) cube complex <-> median graph <-> space with walls <-> almost invariant set equivalences, so I didn't want to say it is completely obvious. Compactness of stabilisers is perhaps a strong enough assumption to get something better.
Feb
21
revised Dicks–Dunwoody almost stability theorem
added 588 characters in body; edited title
Feb
20
asked Dicks–Dunwoody almost stability theorem
Feb
17
awarded  Yearling
Jan
7
comment When can a locally compact group be approximated by discrete subgroups?
I don't know if this helps for the application you have in mind, but for t.d.l.c. groups, an alternative way to approximate the group by discrete objects is to look instead at coset spaces $G/U$ where $U$ ranges over a base of identity neighbourhoods consisting of compact open subgroups. If $G$ is a SIN group, then you can also make $U$ normal in $G$, so $G/U$ is a discrete quotient group of $G$ in the natural sense.
Jan
1
reviewed Approve The injection of direct image sheaf
Dec
10
reviewed Approve Projective closure of affine curve
Dec
10
reviewed Approve Number of spanning trees which contain a given edge
Dec
10
revised Distal actions on coset spaces
added 439 characters in body
Dec
10
revised Can Calabi-Yau manifolds have nonabelian discrete symmetry groups?
edited tags
Dec
7
revised Distal actions on coset spaces
added 175 characters in body
Dec
7
asked Distal actions on coset spaces
Dec
6
reviewed Approve Completion of modules of differentials (A strange exercise in Liu's AG textbook)
Dec
5
reviewed Approve Mystery behind ADE Dynkin diagram
Dec
3
answered Wild automorphisms of profinite groups