Constraint Propagation Example Graph Coloring R G. B *Different-color constraint Initial Domains Arc examined Value deleted R.G.B none R G G Arcs to examine Delete unmentioned tail values .Vi-V, denotes two arcs between V; and Vi Vi<Vj denotes an arc from V, and V.-13 Constraint Propagation Example RG Graph coloring xgtDifferent-color constraint ( R,66 Arc examined value deleted G non Arcs to examine V1V3s V2-V3 Delete unmentioned tail values .V-V denotes two arcs between v and v Vi< Vi denotes an arc from V, and V-1413 Constraint Propagation Example R,G,B R, G G Different-color constraint V1 V2 V3 V1 – V2 none Arc examined Value deleted Graph Coloring Initial Domains R,G,B R, G G V2 V3 V1 Arcs to examine V1-V3, V2-V3 • Vi – Vj denotes two arcs between Vi and Vj . • Vi < Vj denotes an arc from Vj and Vi . • Delete unmentioned tail values 14 Constraint Propagation Example R,G,B R, G G Different-color constraint V1 V2 V3 V1>V3 V1 – V2 none Arc examined Value deleted Graph Coloring Initial Domains R,G,B R, G G V2 V3 V1 Arcs to examine V1<V3, V2-V3 • Vi – Vj denotes two arcs between Vi and Vj . • Vi < Vj denotes an arc from Vj and Vi . • Delete unmentioned tail values