Preserving Partial Solutions while Relaxing Constraint Networks
/ 552 Éric Grégoire, Jean-Marie Lagniez, Bertrand Mazure  This
paper is about transforming constraint networks to accommodate
additional constraints in specific ways. The focus is on two
intertwined issues. First, we investigate how partial solutions
to an initial network can be preserved from the potential impact
of additional constraints. Second, we study how more permissive
constraints, which are intended to enlarge the set of solutions,
can be accommodated in a constraint network. These two problems
are studied in the general case and the light is shed on their
relationship. A case study is then investigated where a more
permissive additional constraint is taken into account through a
form of network relaxation, while some previous partial
solutions are preserved at the same time.