On the multiplicity of weak solutions for a class of coupled quasilinear elliptic systems

Abstract

We study the existence and regularity of weak solutions to the following quasilinear elliptic system: \[ -\mathrm{div}(A_k(x, u_k) |\nabla u_k|^{p_k - 2} \nabla u_k) + \dfrac{1}{p_k} D_s A_k(x, u_k) |\nabla u_k|^{p_k} = g_k(x, u) \quad \text{in } Ω,\quad u_k = 0 \quad \text{on } \partialΩ, \] where $k=1,\dots,d$, $ Ω\subset \mathbb{R}^N $ is a bounded domain with $ N \geq 2 $, $ \boldsymbol{p} = (p_1, \dots, p_d) $, $ p_k > 1 $. Using tools from nonsmooth critical point theory, we prove the existence of infinitely many weak solutions in $ W_0^{1,\boldsymbol{p}}(Ω) \cap L^\infty(Ω; \mathbb{R}^d) $, where $W_0^{1,\boldsymbol p}(Ω)=W_0^{1,p_1}(Ω)\times\dots\times W_0^{1,p_d}(Ω)$.