On super-weakly compact sets and uniformly convexifiable sets
This paper mainly concerns the topological nature of uniformly convexifiable sets in general Banach spaces: A sufficient and necessary condition for a bounded closed convex set C of a Banach space X to be uniformly convexifiable (i.e. there exists an equivalent norm on X which is uniformly convex on C) is that the set C is super-weakly compact, which is defined using a generalization of finite representability. The proofs use appropriate versions of classical theorems, such as James’ finite tree theorem, Enflo’s renorming technique, Grothendieck’s lemma and the Davis–Figiel–Johnson–Pełczyński lemma.