Characterisation of drop and weak drop properties for closed bounded convex sets
John Robilliard Giles, Denka Kutzarova · Bulletin of the Australian Mathematical Society · 1991
Modifying the concept underlying Daneš' drop theorem, Rolewicz introduced the notion of the drop property of a norm which was later generalised to the weak drop property of a norm. Kutzarova extended the discussion to consider the drop property for closed bounded convex sets. Here we characterise the drop and weak drop properties for such sets by upper semi-continuous and compact valued subdifferential mappings.