  Fenchel subdifferential operators of lower semicontinuous proper convex
functions on real Banach spaces are classically characterized as those
operators that are maximally cyclically monotone or, equivalently, maximally
monotone and cyclically monotone. This paper presents an alternative
characterization, which does not involve cyclic monotonicity. In the case of
subdifferential operators of sublinear functions, the new characterization
substantially simplifies. Dually, the new characterization of normal cone
operators is very simple, too.
