From: Narek Saribekyan on
Is there any result on Friedrichs' inequality in anisotropic Sobolev
spaces H0^(p, q) (vanishes on boundary with derivatives up to orders
p-1 and q-1 respectively)?
I want to prove that the bilinear form a(u,v) induced from weak
formulation of homogeneous Dirichlet problem (on a rectangle) for Lu =
(-1)^p du^2p/dx^2p + (-1)^q du^2q/dy^2q is coercive (so I can apply
Lax-Milgram theorem).

a(u,v)=(D^p u, D^p v)+(D^q u, D^q v)

a(u,u) >= c||u||^2 ?

Is L an elliptic operator?

Thanks very much,
Narek
From: Chip Eastham on
On May 2, 3:05 pm, Narek Saribekyan <narek.saribek...(a)gmail.com>
wrote:
> Is there any result on Friedrichs' inequality in anisotropic Sobolev
> spaces H0^(p, q) (vanishes on boundary with derivatives up to orders
> p-1 and q-1 respectively)?
> I want to prove that the bilinear form a(u,v) induced from weak
> formulation of homogeneous Dirichlet problem (on a rectangle) for Lu =
> (-1)^p du^2p/dx^2p + (-1)^q du^2q/dy^2q is coercive (so I can apply
> Lax-Milgram theorem).
>
> a(u,v)=(D^p u, D^p v)+(D^q u, D^q v)
>
> a(u,u) >= c||u||^2 ?
>
> Is L an elliptic operator?
>
> Thanks very much,
> Narek

I think it suffices to know a density result,
that C^inf_0 functions are dense in H^{p,q}_0,
because you can explicitly show coercivity by
integration by parts with a C^inf_0 function.

regards, chip