The equivalence of several basic theorems for subdifferentials
Q. J. Zhu
Abstract: Several different basic properties
are used for developing a system of calculus
for subdifferentials. They are a nonlocal fuzzy sum rule,
a multidirectional mean value theorem, local fuzzy
sum rules and an extremal principle.
We show that all these basic results are equivalent
and discuss some interesting consequences of this equivalence.
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