Another fixed point theorem for nonexpansive potential operators
Biagio Ricceri
Studia Mathematica, Tome 209 (2012), p. 147-151 / Harvested from The Polish Digital Mathematics Library

We prove the following result: Let X be a real Hilbert space and let J: X → ℝ be a C¹ functional with a nonexpansive derivative. Then, for each r > 0, the following alternative holds: either J’ has a fixed point with norm less than r, or sup||x||=rJ(x)=sup||u||L²([0,1],X)=r01J(u(t))dt.

Publié le : 2012-01-01
EUDML-ID : urn:eudml:doc:286548
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     title = {Another fixed point theorem for nonexpansive potential operators},
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     year = {2012},
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Biagio Ricceri. Another fixed point theorem for nonexpansive potential operators. Studia Mathematica, Tome 209 (2012) pp. 147-151. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-sm211-2-3/