We study positive solutions to the boundary value problem $$ \displaylines{ -\Delta_p u - \Delta_q = \lambda f(u) \quad \text{in } \Omega, \cr 0 \text{on \partial\Omega, }$$ where \(q \in (1,p)\) and Ω is a bounded domain in \(\mathbb{R}^N\), \(N>1\) with smooth boundary, \(\lambda\) parameter, \(f:[0,\infty) \to (0,\infty)\) \(C_1\), nondecreasing, p-sublinear at infinity i.e. \(\...