Some geometric properties related to the fixed point theory for nonexpansive mappings 论文

摘要

The main result of this paper asserts that if a Banach space admits a sequentially weakly continuous duality function, then a condition introduced by Opial to characterize weak limits by means of the norm is satisfied and the space has normal structure in the sense of Brodskii-Milman. This result of geometric nature allows some unification in the fixed point theory for both single-valued and multi-valued non-expansive mappings. © 1972 Pacific Journal of Mathematics.