Geodesic
Best approximations, fixed points and parametric projections
Discussiones Mathematicae. Differential Inclusions, Control and Optimization, Tome 22 (2002) no. 2, pp. 243-260

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If f is a continuous seminorm, we prove two f-best approximation theorems for functions Φ not necessarily continuous as a consequence of our version of Glebov's fixed point theorem. Moreover, we obtain another fixed point theorem that improves a recent result of [4]. In the last section, we study continuity-type properties of set valued parametric projections and our results improve recent theorems due to Mabizela [11].
Keywords: fixed point, parametric projection, best approximation, upper semicontinuous, partially closed graph, f-approximatively compact, Oshman space 
Cardinali, Tiziana. Best approximations, fixed points and parametric projections. Discussiones Mathematicae. Differential Inclusions, Control and Optimization, Tome 22 (2002) no. 2, pp. 243-260. http://geodesic.mathdoc.fr/item/DMDICO_2002_22_2_a5/
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