Institute of Mathematics and Informatics Bulgarian Academy of Sciences
Pliska Studia Mathematica Bulgarica, Vol. 12, No 1, (1998), 141p-190p
We survey the relationships between well-posedness and well-behavior. The latter
notion means that any critical sequence (xn) of a lower semicontinuous function
f on a Banach space is minimizing. Here “critical” means that the remoteness of
the subdifferential ∂f(xn) of f at xn (i.e. the distance of 0 to ∂f(xn)) converges
to 0. The objective function f is not supposed to be convex or smooth and the
subdifferential ∂ is not necessarily the usual Fenchel subdifferential. We are thus
led to deal with conditions ensuring that a growth property of the subdifferential
(or the derivative) of a function implies a growth property of the function itself.
Both qualitative questions and quantitative results are considered.