4.4.2 Characteristic Constraints

The constraints characteristic of or for each can be easily expressed in terms of the node representations and .

<Dominance: characteristic constraints>=

proc {Equal N1 N2} N1=N2 end 
proc {NotEqual N1 N2}
   {FS.disjoint N1.eq N2.eq}
end 
proc {Above N1 N2}
   {FS.subset N2.eqdown N1.down}
   {FS.subset N1.equp N2.up}
   {FS.subset N1.side N2.side}
end 
proc {NotAbove N1 N2}
   {FS.disjoint N1.eq N2.up}
   {FS.disjoint N2.eq N1.down}
end 
proc {Disjoint N1 N2}
   {FS.subset N1.eqdown N2.side}
   {FS.subset N2.eqdown N1.side}
end 
proc {NotDisjoint N1 N2}
   {FS.disjoint N1.eq N2.side}
   {FS.disjoint N2.eq N1.side}
end