Enhancing Constraint Propagation with Composition Operators
  Constraint propagation is a general algorithmic approach for pruning the
search space of a CSP. In a uniform way, K. R. Apt has defined a computation as
an iteration of reduction functions over a domain. He has also demonstrated the
need for integrating static properties of reduction functions (commutativity
and semi-commutativity) to design specialized algorithms such as AC3 and DAC.
We introduce here a set of operators for modeling compositions of reduction
functions. Two of the major goals are to tackle parallel computations, and
dynamic behaviours (such as slow convergence).
