Sunto
SiaX un sottoinsieme chiuso e convesso di uno spazio di Banach eT: X→X sia lipschitziana ∈ rotativa, cioè sia ‖Tx−Ty‖≦k‖x−y‖ e ‖T n x−x‖≦a‖Tx−x‖ per qualchek, a reale e per qualche interon>a. Si danno risultati sull’esistenza di punti fissi diT in dipendenza dik, a, n.
Summary
LetX be a closed convex subset of a Banach space andT: X→X a lipschitzian rotative mapping, i.e. such that ‖Tx−Ty‖≦k‖x−y‖ and ‖T n x−x‖≦a‖Tx−x‖ for some realk, a and an integern>a. The paper concernes the existence of fixed point ofT depending onk, a andn.
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(Conferenza tenuta da K. Goebel il 5 giugno 1981)
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Goebel, K., Koter, M. Fixed points of rotative lipschitzian mappings. Seminario Mat. e. Fis. di Milano 51, 145–156 (1981). https://doi.org/10.1007/BF02924817
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DOI: https://doi.org/10.1007/BF02924817