DOI: 10.68381/jca34001 ISSN: 0944-6532

Mosco-Convergence of Convex Sets and Unilateral Problems for Differential Operators with Lower Order Terms Having Natural Growth

Lucio Boccardo, Maria Antonietta Palladino, Marco Picerni

We study the stability of solutions to a class of variational inequalities posed on obstacle-type convex sets, under Mosco-convergence. Specifically, we consider problems of the form

\begin{cases} u \in W_0^{1,p}(\Omega) \cap L^\infty(\Omega), & u \geq \psi \quad \text{ in } \Omega, \\[1mm] \langle A(u), v - u \rangle + \displaystyle\int_{\Omega} H(x, u, D u)(v - u) \geq 0, & \\[3mm] \forall\; v \in W_0^{1,p}(\Omega) \cap L^\infty(\Omega), \quad &v \geq \psi \quad \text{ in } \Omega. \end{cases} { u ∈ W 0 1 , p ( Ω ) ∩ L ∞ ( Ω ) , u ≥ ψ  in  Ω , ⟨ A ( u ) , v − u ⟩ + ∫ Ω H ( x , u , D u ) ( v − u ) ≥ 0 , ∀    v ∈ W 0 1 , p ( Ω ) ∩ L ∞ ( Ω ) , v ≥ ψ  in  Ω .
Here,
A A
is a Leray–Lions type operator, mapping
W_0^{1,p}(\Omega) W 0 1 , p ( Ω )
into its dual
W^{-1, p'}(\Omega) W − 1 , p ′ ( Ω )
, while
H(x, u, D u) H ( x , u , D u )
grows like
|D u|^p ∣ D u ∣ p
. The obstacle
\psi ψ
is a function in
W_0^{1,p}(\Omega) \cap L^\infty(\Omega) W 0 1 , p ( Ω ) ∩ L ∞ ( Ω )
. Our main result establishes that the solutions are stable under Mosco-convergence of the constraint sets. This extends classical stability results to natural growth problems