18,925 reputation
436143
bio website math.berkeley.edu/~theojf
location Berkeley
age 29
visits member for 4 years, 9 months
seen yesterday

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.


1d
comment Removing an article from arxiv
Never use that journal.
2d
comment 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 looks-convenient coordinates.
Jul
14
comment 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
comment 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
comment When is/isn't the monoidal unit compact projective?
@QiaochuYuan In Temperley-Lieb? No. It's the free monoidal category on a self-dual 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
comment Universal ribbon category of ribbon graphs
+1 to the edited version.
Jun
3
comment If $M$ has hyper-kaehler structure then $M//G$ has hyper-kaehler 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
May
10
comment Last Status of Feferman's Conjecture on Indefinite Value of Continuum
I think your question is a good one, but I disagree with your introduction. With the caveat that I'm not a set theorist, it has always seemed to me that $2^{\aleph_0}$ is a perfectly definite number — the question that ZF doesn't answer is rather "how big is $\aleph_1$?".
May
6
awarded  Nice Question
May
6
reviewed Leave Open Does Grothendieck have any pseudonymous paper?
May
3
awarded  Popular Question
Apr
30
comment Are there infinitely many natural numbers not covered by one of these 7 polynomials?
This reads a bit like a homework problem. Please read meta.mathoverflow.net/questions/70, and think about moving your question to our sister site, Math.StackExchange.
Apr
30
accepted I think I have a category enriched in $(\infty,n-1)$-categories. Is it an $(\infty,n)$-category?
Apr
24
awarded  Reviewer
Apr
24
reviewed Leave Open When distance nonincreasing map is an isometry