Some Remarks on Boolean Constraint Propagation
  We study here the well-known propagation rules for Boolean constraints. First
we propose a simple notion of completeness for sets of such rules and establish
a completeness result. Then we show an equivalence in an appropriate sense
between Boolean constraint propagation and unit propagation, a form of
resolution for propositional logic.
  Subsequently we characterize one set of such rules by means of the notion of
hyper-arc consistency introduced in (Mohr and Masini 1988). Also, we clarify
the status of a similar, though different, set of rules introduced in (Simonis
1989a) and more fully in (Codognet and Diaz 1996).
