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This paper is about certain linear subspaces of Banach SN spaces (that is to say Banach spaces which have a symmetric nonexpansive linear map into their dual spaces). We apply our results to monotone linear subspaces of the product of a Banach space and its dual. In this paper, we establish several new results and also give improved proofs of some known ones in both the general and the special contexts. © 2013 Springer Science+Business Media Dordrecht.

We discuss the asjTnmetric sandwich theorem, a generalization of the Hahn-Banach theorem. As appUcations, we derive various results on the existence of linear fanctionals that include bivariate, trivariate and quadrivariate generalizations of the Fenchel duahty theorem. Most of the results are about afhne functions defined on convex subsets of vector spaces, rather than Unear functions defined on vector spaces. We consider both results that use a simple boundedness hypothesis (as in Rockafellar's version of the Fenchel duaUty theorem) and also results that use Baire's theorem (as in the Robinson-Attouch-Brezis version of the Fendiel duaUty theorem). This paper also contams some new results about metrizable topological vector spaces that are not necessarily locally convex. © Heldermann Verlag.

In this paper, we define a Banach SNL space to be a Banach space with a certain kind of linear map from it into its dual, and we develop the theory of linear L-positive subsets of Banach SNL spaces with Banach SNL dual spaces. We use this theory to give simplified proofs of some recent results of Bauschke, Borwein, Wang and Yao, and also of the classical Brezis-Browder theorem. © 2012 Springer Science+Business Media B.V.

In this paper we discuss symmetrically self-dual spaces, which are simply real vector spaces with a symmetric bilinear form. Certain subsets of the space will be called q-positive, where q is the quadratic form induced by the original bilinear form. The notion of q-positivity generalizes the classical notion of the monotonicity of a subset of a product of a Banach space and its dual. Maximal q-positivity then generalizes maximal monotonicity. We discuss concepts generalizing the representations of monotone sets by convex functions, as well as the number of maximally q -positive extensions of a q-positive set. We also discuss symmetrically self-dual Banach spaces, in which we add a Banach space structure, giving new characterizations of maximal q-positivity. The paper finishes with two new examples. © 2012 Springer Basel AG.

In this article, we give conditions under which we can compute the conjugate of a convex function on the product of two Fréchet spaces defined in terms of another convex function on the product of two (possibly different) Fréchet spaces. We use this result to give simple proofs of some (both old and new) results for Banach spaces, and deduce some (both old and new) stability results for strongly representable multifunctions. We take as our starting point a result on closed convex cones in the product of two Fréchet spaces. © 2011 Taylor & Francis.

In this paper, we unify the theory of SSD spaces and the theory of strongly representable sets, and we apply our results to the theory of the various classes of maximally monotone sets. In particular, we prove that type (ED), dense type, type (D), type (NI) and strongly representable are equivalent concepts and, consequently, that the known properties of strongly representable sets follow from known properties of sets of type (ED). © Heldermann Verlag.

We give a new proof based on the recent very elegant argument of Marques Alves and Svaiter that the sub differential of a proper, convex lower semicontinuous function on a real Banach space is maximally monotone. We also show how the argument can be simplified in the reflexive case. © Heldermann Verlag.

In this paper, we show how convex analysis can be applied to the theory of sets that are "positive" with respect to a continuous quadratic form on a Banach space. Monotone sets can be considered as a special case of positive sets, and we show how our results lead to very efficient proofs of a number of results on monotone sets. One of the key techniques that we use is a generalization of the Fitzpatrick function from monotone set theory to an analogous function for positive sets. © Heldermann Verlag.

In this paper, we show how Fitzpatrick functions can be used to obtain various results on the local boundedness, domain and surjectivity of monotone and maximal monotone multifunctions on a Banach space, and also to clarify the relationships between different subclasses of the set of maximal monotone multifunctions. © Heldermann Verlag.