Search type Search syntax
Tags [tag]
Exact "words here"
Author user:1234
user:me (yours)
Score score:3 (3+)
score:0 (none)
Answers answers:3 (3+)
answers:0 (none)
isaccepted:yes
hasaccepted:no
inquestion:1234
Views views:250
Code code:"if (foo != bar)"
Sections title:apples
body:"apples oranges"
URL url:"*.example.com"
Saves in:saves
Status closed:yes
duplicate:no
migrated:no
wiki:no
Types is:question
is:answer
Exclude -[tag]
-apples
For more details on advanced search visit our help page
Results tagged with
Search options not deleted user 33828

Questions about the branch of algebra that deals with groups.

1 vote

Actions of Thompson group F. II

The answer to the question as stated is yes, there is no binary tree as a subgraph for the standard action with standard generators (but there is a binary tree for some generating set). It follows fro …
Dan Sălăjan's user avatar
2 votes

Rotation numbers for amenable group actions on the circle

I think the paper http://arxiv.org/abs/0910.0218 contains nice information related to the questions.
Dan Sălăjan's user avatar
4 votes
Accepted

Uniform bounds on Kazhdan constants in groups

The answer is yes, by Gelander and Zuk: http://www.ams.org/mathscinet/search/publdoc.html?pg1=INDI&s1=697297&vfpref=html&r=24&mx-pid=1910934
Dan Sălăjan's user avatar
5 votes

Actions of Thompson group F

$F$ is bi-orderable, so if you care about actions by homeomorphisms on the line, you can pick up a bi-ordering and produce a dynamical realization: a faithful almost free action ( see Proposition 3.4 …
Dan Sălăjan's user avatar
18 votes

Is there an infinite group with exactly two conjugacy classes?

As a psychological curiosity, Per Enflo writes in his Autobiography that the existence of groups with two conjugacy classes was a key insight behind his many solutions to outstanding problems in Funct …
Dan Sălăjan's user avatar
6 votes
1 answer
500 views

Partition of a group into small subsets

A nonempty subset $S$ of a group $G$ is called small if there is an infinite sequence of elements $g_n$ in $G$ such that the translated sets $g_nS$ are pairwise disjoint. Question: Is there a group …
Dan Sălăjan's user avatar
7 votes
1 answer
653 views

Growth of Thompson's group $F$

EDIT(August 2013): I accepted Mark's answer as being the state of art- there are two relevant references, one in the answer and one in the comments. The minimal growth rate of $F$ remains unknown with …
Dan Sălăjan's user avatar
5 votes

Trees in groups of exponential growth

This (so nice) question seems to be equivalent with the notorious and old problem of constructing a supraamenable (or superamenable) group of exponential growth. Recall that a supraamenable group is o …
Dan Sălăjan's user avatar
15 votes
3 answers
2k views

Folner sets and balls

Several related questions were asked before on MO, but it is not clear to me if the following was settled. Given a finitely generated amenable group, is it always possible to find some finite genera …
Dan Sălăjan's user avatar
21 votes
3 answers
2k views

The role of the Automatic Groups in the history of Geometric Group Theory

What is the role of the theory of Automatic Groups in the history of Geometric Group Theory? Motivation: When I read through the "Word Processing in Groups" I was amazed by the supreme beauty and el …
4 votes
Accepted

Speed of random walks in groups

For nilpotent groups the speed exponent is 0.5. See this paper for the general picture http://arxiv.org/abs/1203.6226 .
Dan Sălăjan's user avatar
16 votes
0 answers
435 views

Splay trees and Thompson's group $F$

( I apologize for only indicating some easy to find references, but new users are not allowed to link more than five). This is very speculative, but: Question: Is there a reformulation of the Dynamic …
Dan Sălăjan's user avatar