Domain may assume 3 forms: Glb..Lub, Glb+Poss or Glb+Poss:Cardinality.
Glb is a ground set denoting the SetVariable's glb. Lub is a ground set denoting the SetVariable's lub. Poss is a ground set denoting the SetVariable's poss (lub\glb). Cardinality is the SetVariable's cardinality, which may be an integer, an FD variable, or an integer domain (list or range).
?- S `:: []..[a,b]. ?- S `:: []+[a,b]. ?- S `:: []+[a,b]:1. ?- S `:: [x]+[a,b]:C. ?- S `:: []+[a,b]:[0,2]. ?- S `:: [c]+[a,b,d,e,f,g,h,i,j,k]:[2,4..7].