bio  website  personal.psu.edu/kes32 

location  Pennsylvania  
age  35  
visits  member for  4 years, 7 months 
seen  1 hour ago  
stats  profile views  4,773 
I'm an assistant professor at Penn State. I work on algebraic geometry and commutative algebra.
1h

comment 
How to check if a symmetric random variables is the difference of two iid symmetric random variables
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16h

reviewed  Close Where to find (personal) motivation 
19h

comment 
Does the canonical morphism commute with the inverse image functor?
This certainly looks commutative to me. Chasing a global section of $F(n)$ (over a chart of $S$) around seems ok (is there some subtlety I'm missing?). Also, in the first displayed equation, shouldn't that be $\Phi^* F(n)$ not $\phi^* F(n)$? 
1d

reviewed  Leave Open Automorphism group of a smooth quadric $Q\subset\mathbb{P}^4$ 
2d

reviewed  Close Expected value when rolling multiple ksided dice and keeping the highest score and 1s cancelling higest remaining values 
Aug 18 
reviewed  Leave Open Linear dependency of real numbers with integer coefficients adding up to zero 
Aug 17 
reviewed  Leave Open Are there two nonhomotopy equivalent spaces with equal homotopy groups? 
Aug 17 
reviewed  Leave Open How short can we state the Axiom of Choice? 
Aug 15 
reviewed  Leave Open Star shaped sets with a midpoint 
Aug 15 
reviewed  Leave Open What is parameterization of the trefoil knot surface in R³? 
Aug 14 
reviewed  Close graph and tree problems helps 
Aug 14 
reviewed  No Action Needed Why is the mirror of resolved conifold the deformed conifold? 
Aug 14 
reviewed  Close Find out acceptance rate / selectiveness of conference 
Aug 13 
reviewed  Close Factoring a semiprime is easier than matrix multiplication? 
Aug 13 
reviewed  Leave Open Natural candidates for 'hyperplanes' in biprojective spaces 
Aug 13 
comment 
Which singularities of log pairs do not depend on the resolution?
Hi, the problem is that for canonical or terminal, you exclude certain divisors, the nonexceptional divisors. As you blowup, more and more valuations become nonexceptional. In particular, if you start with the example I gave you on $\mathbb{A}^2$, the lines have discrepancy $1 + \varepsilon < 0$. But this doesn't stop things from being canonical since they are nonexceptional. The blowup at the origin shows it isn't canonical. On the other hand, for every KLT $(X, \Delta)$ there is a log resolution $Y \to X$ with $(Y, \Delta_Y = K_Y + \pi^*(K_X + \Delta))$ having canonical singularities. 
Aug 12 
reviewed  Leave Open Chow group of zerocycles generated by open dense subscheme 
Aug 12 
comment 
Which singularities of log pairs do not depend on the resolution?
Dear Li Yutong, I don't have KollárMori in front of me, what's the idea of 2.30? The reason that KLT/LC are ok is because there is no distinction between exceptional and nonexceptional discrepancies (note the discrepancy of a nonexceptional divisor is just the coefficient of $\Delta$ along it). In particular, what is exceptional over $X$ is not always exceptional over $Y$. 
Aug 11 
revised 
Which singularities of log pairs do not depend on the resolution?
added 365 characters in body 
Aug 11 
revised 
Which singularities of log pairs do not depend on the resolution?
clarified a point 