Existence of solutions to a periodic boundary value problem (Q2707676)

The authors consider the boundary value problem NEWLINE\[NEWLINE (\varphi (y'(t)))' = f(t, y(t)),\quad 0<t<2\pi , NEWLINE\]NEWLINE with the periodic boundary conditions \(y(0)=y(2\pi)\), \(y'(0)=y'(2\pi)\). Existence results are presented in the resonance case. The function \(\varphi: \mathbb{R} \to (a,b)\) is an increasing homeomorphism with \(\varphi (0)=0 \in (a,b)\).NEWLINENEWLINEFor the entire collection see [Zbl 0933.00035].