The effect of Q-condition in elliptic equations involving Hardy potential and singular convection term
Fessel Achhoud, Abdelkader Bouajaja, Hicham Redwane
TL;DR
This work analyzes quasi-linear elliptic equations with a Hardy potential and singular convection on bounded domains, proving existence and uniqueness of weak solutions under a size condition on coefficients. The authors introduce a regularizing lower-order term $a(x)h(u)$ and develop a truncation-based approximation framework that yields a priori estimates, enabling existence and regularity results for both regular data and $f\in L^1$. They also establish weak and strong maximum principles under sign conditions on the data, and provide an example showing the sharpness of the regularity threshold. The results extend Hardy-type elliptic problems to singular data and nonlinear lower-order terms, with implications for the solvability and qualitative behavior of solutions in critical Sobolev settings.
Abstract
Using an approach by contradiction we prove the existence and uniqueness of a weak solution to a quasi-linear elliptic boundary value problem with singular convection term and Hardy Potential. Whose simplest model is \begin{equation*} \Scale[0.8]{\ds u \in W_0^{1,2}(\mathcal{O})\cap L^\infty(\mathcal{O}) : -Δu=-\mathcal{A}\text{div}\left(\frac{x}{\vert x\vert^2}u\right)+λ\frac{u}{\vert x\vert^2}+f(x),} \end{equation*} where \(\mathcal{O}\) is a bounded open set in \(\mathbb{R}^N\), $\left(\mathcal{A},λ\right) \in \left(0, \infty\right)^2$ and \(f\in W^{-1,2}(\mathcal{O})\). Additionally, by taking advantage of the regularizing effect of the interaction between the coefficient of the zero order term and the datum, we establish the existence, uniqueness and regularity of a weak solution to a quasi-linear boundary value problem whose simplest example is \begin{equation*} \Scale[0.8]{\ds u \in W_0^{1,2}(\mathcal{O})\cap L^\infty(\mathcal{O}) : -Δu +a(x)\vert u\vert^{p-2}u=-\mathcal{A}\text{div}\left(\frac{x}{\vert x\vert^2}u\right)+λ\frac{u}{\vert x\vert^2}+f(x),} \end{equation*} under suitable assumptions on $a$ and $f$.
