Special Session 70: Progress and Challenges in Nonlocal and Nonhomogeneous PDEs

On polyharmonic double phase problems
Tuhina Mukherjee
Indian Institute of Technology Jodhpur
India
Co-Author(s):    Ashutosh Dixit
Abstract:
This talk shall be on study of higher-order doubly critical elliptic problems with weights, driven by a polyharmonic double phase operator. Precisely, problems of the type \begin{equation*} \begin{cases} \mathcal{L}^m_{p,q}(u) = f(x,u) ~&\text{in } \Omega,\ u=\nabla u=\cdots\nabla^{m-1} u=0 &\text{on }{\partial\Omega}, \end{cases} \end{equation*} where $\Omega \subset \mathbb{R}^N$ with $N \geq 2$ is a smooth bounded domain with Lipschitz boundary $\partial\Omega$, $m \in \mathbb{N}$, $1 < p < q < \frac{N}{m}$ with $(N-1)q\leq Np$, the nonlinear term $f\colon\Omega\times\mathbb{R}\to \mathbb{R}$ is Caratheodary function, which has doubly critical growth, and $\mathcal{L}^m_{p,q}$ represents a polyharmonic double phase operator. I shall present suitable Musielak--Orlic--Sobolev framework to study such problems, through application of variational methods. The existence of weak solutions can be derived by establishing a compactness result within these spaces and in addition, the nonexistence results can also be derived under appropriate assumptions by establishing a Pohozaev-type identity for higher-order derivatives. The overall approach is an extension of classical techniques to capture the intricate features of the double phase operator for higher-order derivatives, and shall address the difficulties arising from critical nonlinearities, while also overcoming the non closed feature of truncations in higher order Sobolev spaces.