Svetlin G. Georgieva, Karima Mebarkib
aDepartment of Differential Equations, Faculty of Mathematics and Informatics, University of Sofia, Sofia, Bulgaria.
bLaboratory of Applied Mathematics, Faculty of Exact Sciences, Bejaia University, 06000 Bejaia, Algeria.
The purpose of this work is to establish an extension of a Bai-Ge type multiple fixed point theorem for a sum of two operators. The arguments are based upon recent fixed point index theory in cones of Banach spaces for a k-set contraction perturbed by an expansive operator. As an illustration, our approach is applied to prove the existence of at least three nontrivial nonnegative solutions for a class of eigenvalue three-point boundary value problems (BVPs) for a class of fourth-order ordinary differential equations (ODEs for short).
Keywords: Fixed point index; Cone; Sum of operators; Positive solution.
Georgiev, S., & Mebarki, K. (2021). A new multiple fixed point theory with applications. Advances in the Theory of Nonlinear Analysis and its Application , 5 (3), 393-411.