Journal of Mathematical Physics
Event structures in nonstandard quantum mechanics
Stanley Gudder
Abstract
Event structures in nonstandard quantum mechanics are represented by closed subspaces of a nonstandard Hilbert space. There are four natural types of closed subspaces of a nonstandard Hilbert space and these different types coalesce in the standard theory. These types are the closed internal subspaces, the splitting subspaces, the ⊥-closed subspaces, and the norm-closed subspaces. The algebraic properties of these four types are studied and compared. Moreover, the resulting structures are compared to others that have recently appeared in the literature.