State spaces of JB*-triples

An atomic decomposition is proved for Banach spaces which satisfy some affine geometric axioms compatible with notions from the quantum mechanical measuring process. This is then applied to yield, under appropriate assumptions, a geometric characterization, up to isometry, of the unit ball of the dual space of a JB*-triple, extending a theorem of Friedman and Russo for the atomic case. This result is a non-ordered analog of the Alfsen-Shultz characterizations of state spaces of JB-algebras and C*-algebras. As application, by combining this result with the authors' characterization of TROs ([118] in this archive), an affine operator space characterization is given of TROs, C*-algebras, and one-sided ideals in C*-algebras.

(This paper has appeared in Math. Ann. 328 (2004), 585-624)


Matthew Neal < nealm@denison.edu >

Bernard Russo < brusso@math.uci.edu >