A Hyperdoctrinal View of Constraint Systems

The title sounds scary, but this paper is quite thoughtful and looks crucial to understand the importance and beauty of concurrent constraint programming.

Intuitively, CCP is good because it is so easy and natural to define a denotational semantics for it. This naturality stems from the fact that closure operators are completely defined by sets of their fixpoints, so all combinators on them can be defined in terms of this sets, not functions themselves. And ability to limit attention to closure operators follows from informational approach to computation.