bio | website | math.vt.edu/people/renardym |
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location | Blacksburg, VA | |
age | 60 | |
visits | member for | 4 years, 8 months |
seen | 4 hours ago | |
stats | profile views | 3,200 |
Jul 15 |
comment |
Class of analytically-integrable divergence-free vector fields?
@Robert Bryant: It depends on what you mean by "explicit." On each level curve of the Hamiltonian, you have to solve an autonomous ODE in one dimension. This can always be done in terms of integrations and inverse functions. Of course, whether you can do those "explicitly" is another question, but one that is usually deemed at a "lower level." |
Jul 15 |
answered | Class of analytically-integrable divergence-free vector fields? |
Jul 10 |
comment |
The $L^2\times L^2\to L^2$ norm of the bilinear multiplier operator
Consider what happens when you set $m=\hat f\hat g$. |
Jul 10 |
answered | Bandwidth approximation for a nonlinear problem |
Jul 7 |
awarded | Good Answer |
Jun 23 |
answered | Convergence of sequence of polynomials defined by boundary conditions |
Jun 19 |
comment |
Infinitesimal generator is bounded
A much more serious flaw in your reasoning is that you are overlooking the fact that $t$ is in the denominator and $t\to 0$. |
Jun 17 |
comment |
Is $f(x,y)=\sum_{n\in\mathbb{Z}\backslash\{0\}}\frac{1}{n}e^{2\pi i(xn+yn^2)}$ essentially bounded?
No. Set y=0. You can do the sum explicitly in that case. |
Jun 16 |
reviewed | Edit for which values of $\theta$ does this equation $x_{n+1}=\cos(\theta)x^2_{n}-\sin(\theta)x^2_{n-1}$ have bounded solutions? |
Jun 16 |
revised |
for which values of $\theta$ does this equation $x_{n+1}=\cos(\theta)x^2_{n}-\sin(\theta)x^2_{n-1}$ have bounded solutions?
The body text of the problem was so unregular. |
Jun 16 |
comment |
[This might be a easy question]: A possible trace (inequality) defined under negative Sobolev scale
The problem is that if you pick $f\in H_0^{s+2}$, then $\partial f/\partial\nu$ will be zero on the boundary. |
May 29 |
awarded | Good Answer |
May 26 |
comment |
Existence of Solution steady navier stokes with do nothing outflow condition
First of all, the free boundary condition should be $pn-\nu(\nabla u+(\nabla u)^T)n=0$. Second, what kind of existence results are you looking for? For small data, standard methods work. For large data, there is not much hope if there are free surfaces, as demonstrated by phenomena such as wave breaking, jet breakup etc. |
May 21 |
comment |
Derivatives of radial functions can be bounded by derivatives in terms of radial distance?
This example does not quite seem to work. Does not $d^2f/dr^2$ get large when you actually do the modification near 0? |
May 20 |
answered | Interpolation between weighted $L^p$ spaces |
May 13 |
reviewed | Approve Loop space of manifold |
May 10 |
comment |
Mixed (anisotropic) Sobolev spaces
The correct inference is that $f\in H^s(L^2)\cap L^2(H^s)$. You should look at the equivalent statement for Fourier transforms. |
May 10 |
answered | Mixed (anisotropic) Sobolev spaces |
May 4 |
reviewed | Approve oa.operator-algebras tag wiki excerpt |
May 4 |
reviewed | Approve riemannian-geometry tag wiki |