Reviews in Mathematical Physics
JAUCH–PIRON STATES AND σ-ADDITIVITY
L. J. Bunce, Jan Hamhalter
Abstract
We study σ-additivity of the physically plausible Jauch–Piron states on a von Neumann algebra M. Amongst other consequences we extend our earlier results [5] by showing that geometric conditions much weaker than pureness imply σ-additivity for a Jauch–Piron state and, further, that if M is properly infinite and the continuum hypothesis is assumed to be true then all Jauch–Piron factor states are σ-additive.