Aron-Berner extensions of triple maps with application to the bidual of Jordan Banach triple systems

Abstract

By extending the notion of Arens regularity of bilinear mappings, we say that a bounded trilinear map on Banach spaces id Aron--Berner regular when all its six Aron-Berner extensions to the bidual spaces coincide. We give some results on the Aron-Berner regularity of certain trilinear maps. We then focus on the bidual, $E^{**},$ of a Jordan banach triple system $(E,\pi)$, and investigate those conditions under which $E^{**}$ is itself a Jordan Banach triple system under each of the Aron-Berner extensions of the triple product $\pi.$ We also compare these six triple products with those arising from certain ultrafilters based on the ultrapower formulation of the principle of local reflexivity. In particular, we examine the Aron--Berner triple products on the bidual of a JB$^*$-triple in relation with the so-called Dineen's theorem. Some illuminating examples are included and some questions are also left undecided.