Nontrivial application of Nielsen theory to differential systems
Nielsen theory is one of the few fixed point theories dealing with more than one fixed point. It allows us to obtain a lower estimate for the number of fixed points. The nontrivial application of this theory to differential equations is considered to be a difficult task. The main purpose of this paper is to present a nontrivial example of an application of Nielsen's fixed point theory to a planar system of differential inclusion which has at least two periodic solutions.
scientific article; zbMATH DE number 5116261
scientific article