bio  website  math.rice.edu/~andyp 

location  Houston, TX  
age  35  
visits  member for  5 years, 5 months 
seen  1 hour ago  
stats  profile views  13,895 
associate professor at Rice University
2d

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Math mobile Apps
MO is intended for questions at the mathematics PhD level and above. I've voted to close. 
2d

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Problems concerning meromorphic 1 form on Riemann surface
MO is not for homework. 
Mar 24 
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Probability or odds of something happening
MO is intended for questions at the mathematics PhD level and above. I've voted to close. 
Mar 20 
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seminar about the strong multiplicity one for the Selberg class
Presumably it would be more efficient to just ask Ki? 
Mar 20 
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Framed braids and local systems
No. The correct thing to look at is the space $\widehat{X}_n$ of unordered sets $\{(z_1,v_1),\ldots,(z_n,v_n)\}$, where the $z_i$ are distinct points in $\mathbb{C}$ and $v_i$ is a unit tangent vector based at $z_i$ for all $i$. The fundamental group of $\widehat{X}_n$ is the framed braid group, and local systems on $\widehat{X}_n$ yield representations of the framed braid group. 
Mar 20 
awarded  Favorite Question 
Mar 20 
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Algebraic Number Theory in Financial Mathematics
I feel confident that no interesting insights will be found (though perhaps some fools and their money will be separated). Every time some scientific/mathematical theory gets some popular press, bs artists write papers incorporating the relevant buzzwords. In the 70's it was catastrophe theory, then we got chaos theory and fractals, and now I suppose we get string theory. 
Mar 19 
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cohomology of the orbit space of a group action
@MarkGrant : It's definitely true if $G$ is invertible in $F$ (with the same proof). As for whether the isomorphisms respect cup products, I rather doubt it, though I don't have an example in mind. If $G$ acts freely (so the projection $M \rightarrow M/G$ is a covering map), then the isomorphism is induced by the transfer map. See the answer to mathoverflow.net/questions/58159/… for an example of where this is not a ring homomorphism (though that example is not over a field of characteristic $0$). 
Mar 19 
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Algebraic Number Theory in Financial Mathematics
I'm pretty skeptical of these purported "connections" between financial markets and particle physics. 
Mar 19 
revised 
Ivanov's metaconjecture on surface homeomorphisms.
added 1117 characters in body 
Mar 19 
answered  Ivanov's metaconjecture on surface homeomorphisms. 
Mar 19 
answered  cohomology of the orbit space of a group action 
Mar 18 
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Riemannian simplicial complex and quasiconformal complex
Yes, I believe that is correct. 
Mar 18 
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Riemannian simplicial complex and quasiconformal complex
Robert is talking about the metric properties of these complexes; the rigidity he refers to comes from endowing each simplex with the metric coming from the standard simplex in $\mathbb{R}^n$. 
Mar 18 
awarded  Good Answer 
Mar 14 
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Parodies of abstruse mathematical writing
@ToddTrimble: Wildberger has rather extreme and idiosyncratic views about a supposed lack of rigor in contemporary mathematics. I think the hostility you see is a reaction to the fact that few mathematicians take him very seriously. 
Mar 9 
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Decision problem on triviality of intersection of two subgroups
It is not decidable in general since it would allow you to solve the word problem (given an element $w$, just apply it to the subgroups $\langle w \rangle$ and $\langle w \rangle$; their intersection is trivial if and only if $w$ is trivial). On the other hand, it is decidable for free groups; indeed, using the algorithm described in Stallings's paper "The topology of finite graphs", you can compute the rank of the intersection of two finitely generated subgroups of a free group. 
Feb 27 
answered  Computation of homotopy groups of spheres via PontryaginThom 
Feb 27 
answered  Maps with Hopf invariant zero are suspensions 
Feb 20 
awarded  Nice Answer 