  A ring with effects (e-ring) is a generalization of the ring of bounded
linear operators on a Hilbert space and the subsystem of effect operators
(positive Hermitian operators dominated by the identity operator). The
POV-measures representing (perhaps fuzzy) quantum mechanical observables take
on their valued in the system of Hilbert-space effect operators. We study and
give several examples of e-rings, including von Neumann algebras and rings of
bounded measurable functions.
