A note on solutions of semilinear equations at resonance in a cone
Tom 58 / 1993
Annales Polonici Mathematici 58 (1993), 95-103
DOI: 10.4064/ap-58-1-95-103
Streszczenie
A connection between the Landesman-Lazer condition and the solvability of the equation Lx = N(x) in a cone with a noninvertible linear operator L is studied. The result is based on the abstract framework from [5], applied to the existence of periodic solutions of ordinary differential equations, and compared with theorems by Santanilla (see [7]).