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Fan Zheng
  • Member for 11 years, 5 months
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Density of a functional space
@Dolii The convergence needs to be in $L^2(D)$. This amounts to the boundedness of the the harmonic extension from $L^2(\partial D)$ to $L^2(D)$. I believe this to be true, at least assuming $\partial D$ is smooth enough, but I have yet to find a proof. There is a Springer book The Dirichlet Problem with L2-Boundary Data for Elliptic Linear Equations on that particular problem, which may be helpful to you.
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Density of a functional space
@Dolii What is needed is that $h_n$ converges to something in $L^2(D)$. But this is more difficult than what I have thought.
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Density of a functional space
Yes, and your attempt showed how to approximate when the boundary value is 0. Then you only need to approximate the boundary value in $L^2$, while keeping the Laplacian 0 at the boundary, which can be done using the hint.
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Density of a functional space
Hint: to approximate the boundary value in $L^2$, use a smooth function and then solve the Dirichlet problem with that as the boundary value.
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Degree bounds on coordinates of points in a zero-dimensional variety
Take a simple example with maximal degree $d^n$ (for example, $x_1^d=2$ and $x_{i+1}^d=x_i$, $i=1,\dots,n-1$). Then make the change of coordinates $x_i'=x_i+x_n$, $i=1,\dots,n-1$.
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$L^2$ bound and Sobolev spaces
Do you really mean to put weights in the physical space instead of the frequency space? Then no such bound is possible.
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Localization and containment in commutative ring
On the other hand, the conclusion is true if $R$ is itself a local ring, in which $R_m$ is identical to $R$.
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Localization and containment in commutative ring
Try the simplest example: $R=\mathbb Z$. Then every maximal ideal is of the form $m=(p)$ where $p$ is a prime number. Then $R_m={\mathbb Z}_{(p)}$ is a DVR, so every two ideals are related by containment. On the other hand, there are plenty of pairs of integers $(x,y)$ such that $x\not\mid y$ and $y\not\mid x$.
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Does this property of probability distributions have a name?
I guess they both goes to 0 as $x$ goes to 0, and the property is characterizing the rate at which $F$ goes to 0 as $x$ goes to 0.
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A complete formalization of EGA in Lean
I think it's fitting and proper to invite Kevin Buzzard to this question.
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