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Doing conformal geometry


May
16
answered What is a conormal vector to a domain intuitively?
May
13
comment (Basic) question regarding Einstein-Hilbert-functional / total scalar curvature
By the way, please look at this my answer too.
May
12
comment (Basic) question regarding Einstein-Hilbert-functional / total scalar curvature
I guess that @smiley06 speaks about L^2:={symmetric tensors on a fixed manifold with the L^2 inner product} that is easily shown to be a Hilbert space. I am not too sure if it makes sense to deal with the manifold of all Riemannian metrics but you may ask a question on that on mathoverflow.net where P.Michor is frequently seen :-)
May
12
revised Orientation preserving diffeomorphism.
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May
12
revised Orientation preserving diffeomorphism.
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May
11
comment (Basic) question regarding Einstein-Hilbert-functional / total scalar curvature
Welcome to MathSE and thank you for you question. I admit that it is not easy to find that a very similar question has been already asked and answered here. Please look at this one.
May
10
answered Orientation preserving diffeomorphism.
May
7
comment Figure $\infty$ is immersion of circle
Lemniscate of Bernulli
Apr
30
comment Second derivative of a metric in terms of the Riemann curvature tensor.
If it helped, and you realized what was the problem, please consider adding your own answer :-)
Apr
30
comment Second derivative of a metric in terms of the Riemann curvature tensor.
Sorry, no time to write an answer at the moment, but you can look at this paper for a hint on p.3, or read the whole very detailed story here.
Apr
27
revised Justification for this manipulation in a proof of the first variation of energy formula
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Apr
27
answered Meaning of modulo diffeomorphism
Apr
25
answered Calculating Principal curves
Apr
25
revised Two results on the mean curvature of hypersurfaces
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Apr
25
answered Two results on the mean curvature of hypersurfaces
Apr
25
comment Zeros of the second fundamental form
Thank you for sharing your thoughts. I shall definitely find some time to think about this carefully, but currently I am close to my deadline and have to work hard on my project. Feel free to edit this, add your own answers, etc. It looks like a research level question, so it may be more relevant to crosspost it to mathoverflow.net (please give the link to this question). You may get more active response there.
Apr
23
revised naked singularity and null coordinates
Replaced the link to make the post compliant with the copyright rules.
Apr
22
comment Justification for this manipulation in a proof of the first variation of energy formula
In fact, I believe now that you've spotted a sloppy step in the presented calculation. It is better to use directly $\frac{d}{d s} \langle X, Y \rangle = \langle \nabla_V X, Y \rangle + \langle X, \nabla_V Y \rangle $, as in Lemma 5.2 of J.M.Lee's "Riemannian Manifolds", p.67. Effectively, you don't need the step (2) at all.
Apr
22
comment Justification for this manipulation in a proof of the first variation of energy formula
@Zev Sorry, you are right: $h$ is defined on the rectangle.
Apr
21
comment Justification for this manipulation in a proof of the first variation of energy formula
Think your $h$ defined on $M$, so that $f^* h = h \circ f$ is defined for any smooth $f$. And don't forget the Chain Rule.