Let (M,d) be a metric space, X\subset M be a nonempty closed subset and K\subset M be a nonempty compact subset. By definition, a continuous operator f:X\to X is said to be a Frum-Ketkov operator if there exists l\in ]0,1[ such that d(f(x),K)\le l d(x,K), for every x\in X. In this paper, we will give sufficient conditions ensuring that a Frum-Ketkov operator is weakly Picard. Some generalized Frum-Ketkov operators are also studied.



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Şerban, Marcel-Adrian, Petrușel, Adrian, Rus, Ioan A.