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| bio | website | www-ian.math.uni-magdeburg.de/… |
|---|---|---|
| location | Magdeburg, Germany | |
| age | 30 | |
| visits | member for | 2 years, 5 months |
| seen | May 19 at 23:34 | |
| stats | profile views | 479 |
I am an Australian mathematician.
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May 4 |
awarded | Revival |
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Apr 12 |
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Periodic polynomial? This is wrong -- consider $\prod (1/n)$. |
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Jan 1 |
awarded | Nice Question |
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Dec 2 |
awarded | Yearling |
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Nov 15 |
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characterizing semi-Riemannian spaces of constant curvature Hi Jason. Your example of $S^2\times S^2$ is not with the metric I normally consider (I normally take the flat metric on $S^2\times S^2$). With the round metric, is this still a smooth manifold? Does the condition $\nabla R = 0$ make sense at the transition lines from positive to zero curvature? It seems to me that there are regions with constant positive curvature, and constant zero curvature, and nothing in-between.... I'm probably being dense, but could you shed some light on this? |
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Oct 14 |
answered | An inequality in Evans' PDE |
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Oct 14 |
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An inequality in Evans' PDE It is just $ab \le \frac12a^2 + \frac12b^2$. |
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Oct 14 |
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inverting a cone to a torus You should just edit the one answer... |
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Oct 13 |
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An inequality in Evans' PDE This is just Peter-Paul: the C is not really the same C as on the left. It is $ C^2/2$. |
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Oct 10 |
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A positive “Fourier transform” is integrable What does the complex plane in the subscript mean? |
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Oct 8 |
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signed curvature If this is homework, please add the homework tag. |
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Oct 7 |
asked | Is there a proof of Benford's Law? |
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Oct 6 |
answered | Reversing the Ricci flow |
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Oct 6 |
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Total mean curvature in $L^2$ and minimal surfaces in spaces with non-positive sectional curvature Oh! I had a notational mix-up. That's one problem I don't see ever being solved in differential geometry: some semblance of unification of notation. Nice answer. |
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Oct 5 |
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Total mean curvature in $L^2$ and minimal surfaces in spaces with non-positive sectional curvature I don't understand the application of G-B here. I'm probably being dense, but I thought we had $\int K = 4\pi$ and not $\int S = 8\pi$. (The $S$ is the scalar curvature of the background space, and should be negative, right?) Perhaps you could add a bit more detail there for the slowpokes like me. |
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Oct 5 |
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Total mean curvature in $L^2$ and minimal surfaces in spaces with non-positive sectional curvature Thanks for the answer. I think you'll find that the mean curvature scales like $r^{-1}$; this is easy to remember from the scale invariance of the Willmore energy in Euclidean space: the measure scales like $r^2$ and so the integrand $H^2$ must scale like $r^{-2}$. Or just from thinking about the prinicipal curvatures, which must scale like $r^{-1}$. |
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Sep 28 |
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How do I interpret $F_1, \neg F_1 \vdash F_2$ @Jiew If you know both $F_1$ and $not F_1$ then you have a contradiction. A falsehood. An example is that both the propositions $1+1 = 2$ and $1+1 = 3$ are valid for whatever reason. The rule in your question then gives ANYTHING as a valid consequence. For example, you could conclude $1+1 = 73$, $pigs fly$ or whatever you like. |
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Sep 28 |
answered | How do I interpret $F_1, \neg F_1 \vdash F_2$ |
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Sep 28 |
asked | Total mean curvature in $L^2$ and minimal surfaces in spaces with non-positive sectional curvature |
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Sep 18 |
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Constant tensors and covariant derivatives @Yuri Yes, you're right, it doesn't vanish and will involve second fundamental forms. Also, I think the answer to my other question is no. I guess this question can be closed or if it is preferable I can answer it myself. |
