Boundary-oriented subdifferential characterization of calmness for convex systems

We study subdifferential characterizations of the calmness property for multifunctions representing convex constraint systems in a Banach space. Extending earlier work in finite dimensions, we show that - in contrast to the stronger Aubin property of a multifunction (or metric regularity of its inverse), calmness can be ensured by corresponding weaker constraint qualifications which are based on boundaries of subdifferentials and normal cones only rather than on the full objects