HTab-1.5.4: examples/sat/d_sat7.frm
% SAT
% caused a loop when the saturation for the difference modality was not exhaustive,
% ie when we did not check if the "second different word" was already created
signature { automatic } theory
{
!N1; !P3;
D N1;
P3 v ( E(N1 v N1:P2) & A(N1 v E P3));
E(!P2 & B(!P3));
N1 v A(P2 v D(P3 v <>(P3 & N1)))
}