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bio website math.poly.edu/~yang
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visits member for 4 years, 11 months
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1d
comment Normal-like coordinates for weakly differentiable metrics
Sorry. What you want to do is make the angular dependence singular b
Sep
13
comment Normal-like coordinates for weakly differentiable metrics
I suggest trying to see if this is true for simple examples, before trying to prove the general case. For example, $$g_{ij} = (1+|x|^{2-\alpha})\delta_{ij}$$ where $\alpha > -n/p$.
Sep
11
comment Poincare lemma for non-smooth differentiable forms
Another thing to try are harmonic forms, but this fails, too.
Sep
11
comment Poincare lemma for non-smooth differentiable forms
I agree with Jochen. In particular, I see how to use the standard proof of the Poincaré lemma to get exactness if the same $k$ is used for every term in the sequence. But I don't see how to recover another order of differentiation when proving surjectivity of the last map in the 2d exact sequence given in the question.
Sep
6
answered How is the metric tensor related to the Hessian of the first fundamental form?
Sep
5
comment How is the metric tensor related to the Hessian of the first fundamental form?
What do you mean by the "first fundamental form? Or its Hessian? As far as I know, the term "first fundamental form" is used mainly for a submanifold of Euclidean space and refers to the induced Riemannian metric on the submanifold.
Sep
3
awarded  ap.analysis-of-pdes
Aug
11
comment Writing papers in pre-LaTeX era?
Sorry but no way. And it might have been Swiss.
Aug
1
awarded  Nice Answer
Jul
31
comment Why does Neeman avoid t-structures?
I don't really see the point of asking this question here, when you can easily try asking the author via email.
Jul
22
awarded  Good Question
Jul
21
comment Negative impact of wrong or non-rigorous proofs
Come to think of it, I heard not that long ago about an entire field full of what you all are talking about, a field from which any sensible young person would flee, even if they love the subject. Forgive me. I'm getting old and my memory is terrible.
Jul
20
awarded  Popular Question
Jul
20
comment Negative impact of wrong or non-rigorous proofs
user36931, I agree.
Jul
20
comment Negative impact of wrong or non-rigorous proofs
Let me add that I don't see evidence for the claim that people doing the "cleaning up" receive little credit. If "cleaning up" means filling in routine details, then it's generally acknowledged that the original proof is in fact a rigorous one. If, on the other hand, "cleaning up" requires the introduction of new ideas or techniques, then it appears to me that the people doing this are given a lot of credit and the fact that their work provides rigorous proofs of the "theorems" of a prominent mathematician makes it look only better and not worse.
Jul
20
comment Negative impact of wrong or non-rigorous proofs
S. Carnahan, that's a good point. I'm willing to entertain rumors about this really happening.
Jul
20
revised Negative impact of wrong or non-rigorous proofs
edited tags
Jul
20
comment Negative impact of wrong or non-rigorous proofs
Lee, thanks. I agree.
Jul
19
comment Negative impact of wrong or non-rigorous proofs
Yemon, can you cite a specific example where you believe this happened?
Jul
19
accepted Point of maximal distance on a non-positively curved PL surface