bio  website  math.berkeley.edu/~qchu 

location  Berkeley, CA  
age  24  
visits  member for  5 years, 5 months 
seen  6 hours ago  
stats  profile views  59,002 
I am a thirdyear graduate student at UC Berkeley. I'm interested in the interplay between homotopy theory, quantum field theory, manifold topology, and higher category theory.
20h

answered  Simply connected Lie groups homeomorphic to R^n are solvable 
1d

answered  Has any attempt been made to classify finite groupoids? 
2d

comment 
When does the Borel construction have the homotopy type of a CWcomplex?
Presumably this depends on a choice of $EG$. What $EG$ are you choosing? 
2d

awarded  Nice Answer 
2d

awarded  Necromancer 
2d

revised 
UFD and fundamental group
deleted 13 characters in body 
2d

comment 
StiefelWhitney class of complex projective spaces
Crossposted: math.stackexchange.com/questions/1206867/… 
2d

answered  UFD and fundamental group 
Mar 25 
comment 
Moduli space of flat connections over a torus
It is not a manifold in general. Lots of stuff is known about these sorts of spaces; one keyword you can use is "character variety." 
Mar 25 
revised 
Generators of invariant polynomials of semisimple Lie algebra
added 287 characters in body 
Mar 25 
comment 
Moduli space of flat connections over a torus
What do you mean by "known"? The moduli space of flat $G$connections on a torus is the space $\{ (g, h) \in G^2 : gh = hg \}$ of commuting pairs of elements of $G$ ($g, h$ are given by monodromy around a pair of generators of $\pi_1$) modulo the action of $G$ given by simultaneous conjugation. What does it mean to know this space? 
Mar 25 
answered  What is an infinite prime in algebraic topology? 
Mar 25 
revised 
Generators of invariant polynomials of semisimple Lie algebra
deleted 1 character in body 
Mar 25 
answered  Generators of invariant polynomials of semisimple Lie algebra 
Mar 25 
comment 
Galois cohomology out of the classifying stack
Cohomology of a stack is contravariant in the stack, but Galois cohomology is covariant in $G$. 
Mar 25 
comment 
Generators of invariant polynomials of semisimple Lie algebra
@David: that's a basis of symmetric functions as a vector space, not a choice of generators as an algebra. 
Mar 23 
comment 
Are there any natural differential operators besides $d$?
@David: I haven't thought very hard about this, but can't you do things like consider an extension of $d$ to symmetric powers of $1$forms? 
Mar 22 
comment 
Are there any natural differential operators besides $d$?
@Daniel: the Lie derivative and contractions are natural with respect to diffeomorphisms, but they are not natural with respect to arbitrary smooth maps (since vector fields can't be transported along arbitrary smooth maps). 
Mar 22 
comment 
Are there any natural differential operators besides $d$?
Natural Operations in Differential Geometry is dedicated to answering questions of this form: emis.de/monographs/KSM/kmsbookh.pdf 
Mar 21 
answered  Isomorphism of various gauge groups under homotopy 