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Stronger maximal monotonicity properties of linear operators

Published online by Cambridge University Press:  17 April 2009

H.H. Bauschke
Affiliation:
Department of Mathematics and StatisticsOkanagan University College3333 College WayKelowna, BC V1V 1V7Canada e-mail: bauschke@cecm.sfu.ca
S. Simons
Affiliation:
Department of MathematicsUniversity of CaliforniaSanta Barbara CA 93106–3080United States of America e-mail: simons@math.ucsb.edu
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Abstract

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The subdifferential mapping associated with a proper, convex lower semicontinuous function on a real Banach space is always a special kind of maximal monotone operator. Specifically, it is always “strongly maximal monotone” and of “type (ANA)”. In an attempt to find maximal monotone operators that do not satisfy these properties, we investigate (possibly discontinuous) maximal monotone linear operators from a subspace of a (possibly nonreflexive) real Banach space into its dual. Such a linear mapping is always “strongly maximal monotone”, but we are only able to prove that is of “type (ANA)” when it is continuous or surjective — the situation in general is unclear. In fact, every surjective linear maximal monotone operator is of “type (NA)”, a more restrictive condition than “type (ANA)”, while the zero operator, which is both continuous and linear and also a subdifferential, is never of “type (NA)” if the underlying space is not reflexive. We examine some examples based on the properties of derivatives.

Type
Research Article
Copyright
Copyright © Australian Mathematical Society 1999

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