L- and M-weakly compact multilinear operators and their linear adjoints

TL;DR

This paper characterizes the conditions under which the linear adjoint of multilinear operators between Banach spaces and lattices are weakly compact, developing new theory for their linear adjoints and properties.

Contribution

It introduces a comprehensive theory of linear adjoints for multilinear operators between Banach lattices and establishes equivalences for weak compactness properties.

Findings

The linear adjoint of a multilinear operator is M-weakly compact iff the original is L-weakly compact.

Multilinear operators of order bounded variation are continuous between Banach lattices.

The paper develops the theory of linear adjoints for multilinear operators in Riesz spaces.

Abstract

Let $X_1, \ldots, X_m$ be Banach spaces and let $E_1, \ldots, E_m,F$ be Banach lattices. Our main results read as follows: (i) The linear adjoint $A^*$ of a continuous multilinear operator $A \colon X_1 \times \cdots \times X_m \to F$ is $M$-weakly compact if and only if $A$ is $L$-weakly compact. (ii) The linear adjoint $A^*$ of a multilinear operator of order bounded variation $A \colon E_1 \times \cdots \times E_m \to F$ is $L$-weakly compact if and only if the linearization of $A$ on the positive projective tensor product is $M$-weakly compact. In our way to prove these results, we develop the basic theory of linear adjoints of multilinear operators between Riesz spaces, we prove that multilinear operators of order bounded variation between Banach lattices are continuous, and we explore different notions of multilinear operators of $M$-weakly compact-type.