International Journal of Mathematics and Mathematical Sciences · 1987 · 41 citations · 1 references
Natural SciencesMathematicsDifferential EquationsDynamical SystemsSet TheoryFixed Point TheoryFixed PointsFunctional AnalysisMetric GeometryOperator TheoryContraction PrincipleExistence Of Fixed PointsFunctional EquationsMetric Fixed Point TheoryMonotone MappingsRegularity CriteriaUniqueness Of Fixed Points
In this Der, we show the existence of solutions of functional equations fx ∈ sx∩tx and x=fx ∈ sx∩Tx under certain contraction and asymptotic regularity conditions, where f, S and T are single‐valued and multl‐valued mappings on a metric space, respectively. We also observe that MukherJee′s fixed point theorem for a single‐valued mapping commuting with a multl‐valued mapping admits of a counterexample and suggest some modifications. While doing so, we also answer an open question raised in [I] and [2]. Moreover, our results extend and unify a multitude of fixed point theorems for multi‐valued mappings.
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