Chong LI, Genaro LOPEZ
LetB(resp.K,BC,KC) denote the set of all nonempty bounded (resp. compact, bounded convex, compact convex) closed subsets of the Banach spaceX, endowed with the Hausdorff metric, and letG be a nonempty relatively weakly compact closed subset ofX. LetBostand for the set of allF∈B such that the problem (F,G) is well-posed. We proved that, ifX is strictly convex and Kadec, the setKC∩Bo is a denseGδ-subset ofKC\G. Furthermore, ifX is a uniformly convex Banach space, we will prove more, namely that the setB\Bo (resp.K\Bo,BC\Bo,KC\Bo) isσ-porous inB (resp.K,BC,KC). Moreover, we prove that for most (in the sense of the Baire category) closed bounded subsetsGofX, the setK\Bo is dense and uncountable inK.