Abstract
Let (X,d) be a Polish space, CB(X) the family of all nonempty
closed and bounded subsets of X, and (Ω,Σ) a
measurable space. A pair of a hybrid measurable mappings f:Ω×X→X and T:Ω×X→CB(X), satisfying the inequality (1.2), are introduced and
investigated. It is proved that if X is complete, T(ω,⋅), f(ω,⋅) are continuous for all ω∈Ω, T(⋅,x), f(⋅,x) are measurable for all x∈X, and f(ω×X)=X for each ω∈Ω, then there is a measurable
mapping ξ:Ω→X such that f(ω,ξ(w))∈T(ω,ξ(w)) for all ω∈Ω. This result generalizes
and extends the fixed point theorem of Papageorgiou (1984) and many
classical fixed point theorems.