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bio website sas.upenn.edu/~vnanda
location Philadelphia, PA
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visits member for 3 years, 6 months
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Currently a post-doc at Penn, was a graduate student at Rutgers. Here are some papers, some software, and a seminar.


Apr
15
comment Find a shortest way between nodes in graph
See en.wikipedia.org/wiki/Dijkstra%27s_algorithm Since this question does not appear to be research-level, I am voting to move it to math.stackexchange
Apr
3
revised Between Tietze's and Dugundji's Extension Theorems
deleted 70 characters in body
Apr
3
answered Between Tietze's and Dugundji's Extension Theorems
Apr
3
comment Between Tietze's and Dugundji's Extension Theorems
Pietro, the answer to Q3 is also no -- set $X$ = the Michael line (which is Hausdorff) and let $Y$ be the rationals. Then you can't find a bounded linear extension even for $E = \mathbb{R}^n$
Apr
1
comment Between Tietze's and Dugundji's Extension Theorems
Could you clarify what you're really looking for in Q1? Dugundji's theorem, in a slightly generalized form, gives more than a function-wise extension of every $f:A \to Y$ to $F:X \to Y$ where $A \subset X$ and $Y$ is LCTVS -- it asserts a simultaneous extension via a linear map $C(A,Y) \to C(X,Y)$. Are you looking for function-wise extensions or a single simultaneous extension?
Feb
27
comment Relating overlapping simplicial complexes
@TylerLawson If $A$ and $B$ are arbitrary aside from being connected, and if $C$ is a point, then your condition is immediately satisfied since both kernels are trivial, no? I don't think one can deduce the existence of a chain map in this case, but perhaps I have misunderstood your comment.
Feb
27
comment Relating overlapping simplicial complexes
There must be more here that you have in mind but haven't written down: the intersection could just be a single vertex without imposing any seriois constraints on the two subcomplexes!
Feb
18
reviewed Approve Homology equivalence and isomorphism on $\pi_1$ not enough for homotopy equivalence?
Feb
18
reviewed Approve Cohomology spectral sequence over $k[t]$
Feb
18
comment Intuitive Approach to Sheaf and Cech Cohomology
@,Jjm Nothing! We can just leave it here and the stackexchange automatons will deal with it :)
Feb
18
comment Intuitive Approach to Sheaf and Cech Cohomology
Dear Jjm, I have cast the final vote to close since your question is more suited for math stackexchange, where I hope it will receive the comprehensive answer that it deserves. I also suggest that you modify it there by removing the erroneous reference to Dolbeault cohomology.
Feb
16
reviewed Approve Resources to learn about hypergraphs
Feb
15
reviewed Approve soft-question tag wiki
Feb
15
reviewed Approve soft-question tag wiki excerpt
Feb
14
awarded  Popular Question
Feb
8
comment How to approach the stigma of not having a math degree?
I'm sorry your question was closed - your situation is actually not too different from the one experienced by PhD candidates! The quickest way is to convince the mathematician that you know your stuff already. If someone condescendingly says "well, there is a famous theorem relating curvature to Euler characteristic", you should immediately respond with "how is Gauss-Bonnet relevant here?" instead of with sighs of frustration. We're a laconic lot in general, and would be happier to not have to explain things :)
Feb
5
comment consistent orientation for functorial pull-push in generalized cohomology
In the first line, do you mean the twisted $E$-cohomology of $X_{out}$ rather than of the undefined $E_{out}$? Cool question, though.
Jan
20
awarded  Notable Question
Jan
7
comment Are there good ways of relating a minor to the full determinant?
Well, $\text{det}(B)$ is a sum of $n$ terms and only one of them is a multiple of $\text{det}(A)$. So you can't expect much here without severely constraining that additional row and column, can you?
Jan
4
comment Sampling from a Manifold
I hope you are familiar with the work of niyogi, smale and weinberger (people.cs.uchicago.edu/~niyogi/papersps/NiySmaWeiHom.pdf) which assumes that the manifold in question has been embedded in euclidean space and provides bounds on the sample size in terms of the injectivity radius to extract homotopy type with high confidence.