Source : Free On-Line Dictionary of Computing

incremental constraint solver
     
        A system in which a {constraint solver} is given {constraint}s
        one at a time by an {inference engine} (as is found in
        {Prolog}).  The solver adds the new constraint to an initially
        empty set of solved constraints.  If the new constraint is
        consistent with the solved constraints it will be added to the
        set.  If it was inconsistent, the inference engine
        {backtrack}s.  This is the basis of {Constraint Logic
        Programming}.
     
        (1994-11-01)