bio  website  math.berkeley.edu/~theojf 

location  Berkeley  
age  29  
visits  member for  4 years, 11 months 
seen  2 hours ago  
stats  profile views  13,928 
I am a recent graduate from UC Berkeley. Starting Fall 2013, I am a Boas Assistant Professor at Northwestern University. My research is broadly centered on quantum field theory — my interests include category theory, representation theory, homological algebra, algebraic topology, Poisson geometry, and theoretical physics.
4h

answered  Recognize this strange expression from linear algebra? 
5h

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Recognize this strange expression from linear algebra?
@SteveHuntsman Maybe $g_{kl}$ in place of $c_{kl}$? 
5h

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Are linear algebraic groups rigid?
I don't really know the general definition of "reductive", but is this $G$ reductive "over $k[t]$"? There are many examples of reductive groups degenerating to solvable groups, of which this is a particularly nice one. 
Aug 12 
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Hyperfinite type II_1 factor as the Clifford algebra
I am far from an expert. My impression is that "the hyperfinite II_1 factor" has lots of automorphisms, and different manifestations of it, although isomorphic, often are not canonically isomorphic. The classification of factors only says that a given one is isomorphic to the hyperfinite II_1 factor, and doesn't tell you that they are really "the same" in any meaningful way. But I repeat: I am far from an expert. 
Aug 9 
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What's the state of affairs concerning the identification between quantum group reps at root of unity, and positive energy affine Lie algebra reps?
Great question! I have nothing useful to contribute towards an answer. 
Aug 2 
awarded  Popular Question 
Aug 2 
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String diagrams for bimodules over noncommutative algebras?
@DavidRoberts: Sorry for the slow response. Yes, of course JoyalStreet  I clearly wasn't thinking straight, and went "Street was one of the names ... what's the name that goes with Street?" 
Jul 28 
answered  String diagrams for bimodules over noncommutative algebras? 
Jul 22 
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Removing an article from arxiv
Never use that journal. 
Jul 22 
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When does a monoidal functor between ribbon categories preserve cups and caps, but not necessarily braidings?
Right. The strong monoidal functor from supervector spaces to $(\mathbb Z/2)$modules (with the usual symmetric structure) does not preserve quantum dimension. And any two (right, say) duals are canonically isomorphic, but that isomorphism often is not the identity for some looksconvenient coordinates. 
Jul 14 
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Are there isomeasure simplices?
I assume you are familiar with Schanuel's excellent paper "What is the length of a potato?", but your notion of isomeasure reminded me of it, so in the off chance you don't know that paper, I thought I'd mention it. 
Jul 7 
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When is/isn't the monoidal unit compact projective?
@NoahSnyder Thanks! And indeed I should have remembered that from your paper with Chris and Chris. 
Jul 6 
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When is/isn't the monoidal unit compact projective?
@QiaochuYuan In TemperleyLieb? No. It's the free monoidal category on a selfdual object of that dimension. Given any monoidal category, you can ask how many braidings it admits. In the case of TL, there are precisely four (which are interchanged under $q \mapsto q$ and $q\mapsto q^{1}$). 
Jul 5 
asked  When is/isn't the monoidal unit compact projective? 
Jul 2 
awarded  Socratic 
Jul 2 
awarded  Inquisitive 
Jul 2 
awarded  Curious 
Jun 29 
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Universal ribbon category of ribbon graphs
+1 to the edited version. 
Jun 3 
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If $M$ has hyperkaehler structure then $M//G$ has hyperkaehler structure?
I have seen this Kahler quotient called $M //// G$, in keeping with the idea that in $M//G$ we subtract $G$ off twice. 
May 29 
awarded  Nice Question 