7,593 reputation
11728
bio website math.vt.edu/people/renardym
location Blacksburg, VA
age 59
visits member for 3 years, 11 months
seen 10 mins ago

35m
comment Is the ISC kaput
Which web address did you try? I just tried this one: oldweb.cecm.sfu.ca/projects/ISC/ISCmain.html and it seems to work fine.
1h
comment Disruptive innovations in mathematical notations
Don't ever use the word "disruptive" in a proposal! Everybody knows the right word is "transformative"!
Oct
20
answered orthonormal basis or Parseval frame for Sobolev spaces
Oct
15
answered A hyperbolic partial differential equation (wave-like) with variable-dependent coefficient and possibly singular in one variable
Oct
1
answered Solvability of quasilinear elliptic equations on closed manifolds
Sep
30
awarded  Enlightened
Sep
30
awarded  Nice Answer
Sep
28
comment A distributional normal derivative for functions in $H^1(\Omega)$
$H^1(\Omega)^*$ is not a space of distributions in $\Omega$. For instance, the functional on the left hand side of your equation is in $H^1(\Omega)^*$. This defeats the objective of separating the inhomogeneous term in the PDE from the boundary condition.
Sep
24
comment A problem that involves matrix and Lorentz Transformation
You can fill up two-dimensional matrices with zeros and make them four-dimensional.
Sep
24
answered A problem that involves matrix and Lorentz Transformation
Sep
24
comment $C^0$ estimate for solutions of elliptic PDE with Neumann BC
If f and h are bounded, they are in every $L^p$. You can then get what you want by using $L^p$ estimates and Sobolev embedding.
Sep
23
answered Books on the analysis of hyperbolic partial differential equations
Sep
15
comment Eigenstates of Fourier transformation
I don't see why this makes any difference. Voting to close as a duplicate.
Sep
15
awarded  Nice Answer
Sep
15
comment Decay of weak solutions to degenerate parabolic PDEs on manifolds without boundary
Questions like this always leave me with the impression that the poster has not done his/her homework to an appropriate extent. I mean, there are only about a bazillion or so papers in the literature about porous media and similar equations. So in a question like this, I would rather expect something along the lines of: I have read Refs. [1]-[20], and I have concluded X, but this still leaves Y unanswered.
Sep
13
comment Solving a non linear equation
Why the votes to close? Is there a simple argument for uniqueness that some of us are missing?
Sep
9
comment Linear interpolation in weighted Sobolev spaces
How did you prove functions in $W_{2,0}$ are bounded? Did you not do this by showing that the $L^\infty$ norm is bounded in terms of the $W_{2,0}$ norm? You also say you know $C^\infty$ functions are dense. So you have a uniformly convergent sequence of $C^\infty$ functions. This implies the limit is continuous.
Sep
8
comment Can a monotone exponentially decreasing function be uniformely approximated bt Gaussians?
Then the answer is different and approximation is possible. For instance, you can set $\exp(-x^2)=u$ and $f(x)=g(u)$. Now use the Weierstrass approximation theorem to approximate g by a polynomial on the interval [0,1].
Sep
8
answered Can a monotone exponentially decreasing function be uniformely approximated bt Gaussians?
Sep
7
comment Determinant inequality involving Hermitian, positive definite matrices
Why do your expect this to be true? Have you compiled extensive evidence or is this posed somewhere as a problem?