We present a unified framework for the management of stored data, deci
sion models, and assertions in two-valued logic, based on the algebra
of relations and on the operation of relational division. This powerfu
l operation was developed in the context of stored data, and it also h
as limited applicability to models and assertions. The strength and we
akness of division is that it allows universal quantification of certa
in queries on partitioned relations. We extend this concept by introdu
cing a new operation, relational pseudodivision, which replaces univer
sal with existential quantification and thus enlarges the set of avail
able partitioning operations.