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bio website math.berkeley.edu/~ianagol
location Berkeley
age 45
visits member for 5 years, 10 months
seen 22 hours ago

I'm a professor at UC Berkeley working predominantly in the field of low-dimensional topology.


15h
awarded  Nice Answer
Aug
19
comment Questions on poincare homology spheres and branched covers
You can use the orbifold theorem to answer Question 1. en.wikipedia.org/wiki/William_Thurston#Orbifold_theorem
Aug
13
comment Negatively curved metrics minimizing the length of a homotopy class of simple closed curves
By the precompactness theorem - see the third paragraph.
Aug
5
awarded  Enlightened
Jul
31
answered Hausdorff Dimensions of Limit set of subgroups of SL(2,Z)
Jul
30
comment Surgery along an arc connecting the components of a $2$-component link gives the unknot
I think this observation underlies the other papers I linked to.
Jul
30
comment Surgery along an arc connecting the components of a $2$-component link gives the unknot
Hey Jim - the paper has nothing to do with Schoenfies - it's about 2-spheres embedded in $\mathbb{R}^4$ with 4 critical points. Saying such a sphere is standard is equivalent to saying that any band sum of the 2-component unlink which gives the unknot is standard. Scharlemann proves this actually for split links. A simpler proof was found later by Thompson. dx.doi.org/10.1016/0040-9383(87)90060-7
Jul
30
revised Surgery along an arc connecting the components of a $2$-component link gives the unknot
added 368 characters in body
Jul
30
answered Surgery along an arc connecting the components of a $2$-component link gives the unknot
Jul
28
awarded  Nice Answer
Jul
28
comment Is every nonabelian finite simple group a quotient of a triangle group $(a,b,c)$ with $a,b,c$ coprime?
I believe most finite simple groups are generated by elements of order 2 and 3, which addresses the 2nd part of your question. mathoverflow.net/a/59300/1345
Jul
28
revised Intuition behind the Morse inequalities?
added 5 characters in body
Jul
27
answered Intuition behind the Morse inequalities?
Jul
21
comment Torsion in profinite groups
By intersect trivial, you mean intersect in the identity element? I don't see why this follows from point-set topology.
Jul
21
comment Torsion in profinite groups
Maybe you can expand the argument in your fourth sentence - I don't understand why one has only finitely many conjugates to intersect in the identity.
Jul
15
awarded  Enlightened
Jul
15
awarded  Nice Answer
Jul
15
comment the space of continuous maps between 3-manifolds
This was explained here: mathoverflow.net/a/19562/1345
Jul
9
answered Your favorite papers on geometric group theory
Jul
2
awarded  Nice Answer