Glen Wheeler
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 May 4 awarded Revival Apr 12 comment Periodic polynomial? This is wrong -- consider $\prod (1/n)$. Jan 1 awarded Nice Question Dec 2 awarded Yearling Nov 15 comment 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? Oct 14 answered An inequality in Evans' PDE Oct 14 comment An inequality in Evans' PDE It is just $ab \le \frac12a^2 + \frac12b^2$. Oct 14 comment inverting a cone to a torus You should just edit the one answer... Oct 13 comment An inequality in Evans' PDE This is just Peter-Paul: the C is not really the same C as on the left. It is $C^2/2$. Oct 10 comment A positive “Fourier transform” is integrable What does the complex plane in the subscript mean? Oct 7 asked Is there a proof of Benford's Law? Oct 6 answered Reversing the Ricci flow Oct 6 comment 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. Oct 5 comment 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. Oct 5 comment 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 $r^{-1}$. Sep 28 comment 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. Sep 28 answered How do I interpret $F_1, \neg F_1 \vdash F_2$ Sep 28 asked Total mean curvature in $L^2$ and minimal surfaces in spaces with non-positive sectional curvature Sep 18 comment 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. Sep 18 comment Constant tensors and covariant derivatives @Yuri I mean for $\text{Ric}$ to act on $T\Sigma$, although I'm not sure if it turns out to be better for it to act on the pullback bundle. Can you explain why you don't think the expression is well-defined either way? Let's just take $X\in\{e_1,e_2\}$. What I mean by "connection in the normal bundle" is just the projection of $\nabla$ onto $(T\Sigma)^\perp$. Sorry that I am being confusing.