Abstract:Abstract. In this paper we give two partial answers to Fryszkowski's problem which can be stated as follows: given α ∈ (0, 1), an arbitrary non-empty set Ω and a set-valued mapping F : Ω → 2 Ω , find necessary and (or) sufficient conditions for the existence of a (complete) metric d on Ω having the property that F is a Nadler set-valued α-contraction with respect to d. More precisely, on the one hand, we provide necessary and sufficient conditions for the existence of a complete and bounded metric d on Ω havin… Show more
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