lab([required,strong,prefer,weak]). 

********* using LPB ***********

?-solve_constr_hier([[X=Y,Z\=Y,X=b,Z=b]@strong,[Y=c]@weak],[[]],A).

X = b 
Y = b 
Z = _769 
A = [_769\=b] ;

X = c 
Y = c 
Z = b 
A = [] ;

X = b 
Y = b 
Z = b 
A = [] ;

X = b 
Y = c 
Z = b 
A = [] ;

no

?-solve_constr_hier([[X=a,Y=b,Y\=b]@strong],[[X=Y]],A).

X = a 
Y = a 
A = [] ;

X = b 
Y = b 
A = [] ;

no

?-solve_constr_hier([[X=a,Y=b,Y\=b]@strong,[Y=b]@prefer],[[X=Y]],A).

X = a 
Y = a 
A = [] ;

X = b 
Y = b 
A = [] ;

no

********* using RPB ***********

?-solve_constr_hier([[X=Y,Z\=Y,X=b,Z=b]@strong,[Y=c]@weak],[[]],A).

X = b 
Y = c 
Z = b 
A = [] ;

X = c 
Y = c 
Z = b 
A = [] ;

no

?-solve_constr_hier([[X=a,Y=b,Y\=b]@strong],[[X=Y]],A).

X = b 
Y = b 
A = [] ;

X = a 
Y = a 
A = [] ;

no

?-solve_constr_hier([[X=a,Y=b,Y\=b]@strong,[Y=b]@prefer],[[X=Y]],A).

X = b 
Y = b 
A = [] ;

no

********* using UCB ***********

?-solve_constr_hier([[X=Y,Z\=Y,X=b,Z=b]@strong,[Y=c]@weak],[[]],A).

X = b 
Y = c 
Z = b 
A = [] ;

X = c 
Y = c 
Z = b 
A = [] ;

no

?-solve_constr_hier([[X=a,Y=b,Y\=b]@strong],[[X=Y]],A).

X = a 
Y = a 
A = [] ;

no

?-solve_constr_hier([[X=a,Y=b,Y\=b]@strong,[Y=b]@prefer],[[X=Y]],A).

X = a 
Y = a 
A = [] ;

no

********* using WSB ***********

?-solve_constr_hier([[(X=Y,1),(Z\=Y,1),(X=b,1),(Z=b,1)]@strong,[(Y=c,1)]@weak],[[]],A).

X = b 
Y = c 
Z = b 
A = [] ;

X = c 
Y = c 
Z = b 
A = [] ;

no

?-solve_constr_hier([[(X=a,1),(Y=b,1),(Y\=b,1)]@strong],[[X=Y]],A).

X = a 
Y = a 
A = [] ;

no

?-solve_constr_hier([[(X=a,1),(Y=b,2),(Y\=b,1)]@strong],[[X=Y]],A).

X = b 
Y = b 
A = [] ;

X = a 
Y = a 
A = [] ;

no

?-solve_constr_hier([[(X=a,1),(Y=b,1),(Y\=b,1)]@strong,[(Y=b,1)]@prefer],[[X=Y]],A).

X = a 
Y = a 
A = [] ;

no

?-solve_constr_hier([[(X=a,1),(Y=b,2),(Y\=b,1)]@strong,[(Y=b,1)]@prefer],[[X=Y]],A).

X = b 
Y = b 
A = [] ;

no

********* using WCB ***********

?-solve_constr_hier([[(X=Y,1),(Z\=Y,1),(X=b,1),(Z=b,1)]@strong],[[]],A).

X = b 
Y = _3028 
Z = b 
A = [b\=_3028] ;

X = b 
Y = b 
Z = b 
A = [] ;

X = _3027 
Y = _3027 
Z = b 
A = [b\=_3027] ;

X = b 
Y = b 
Z = _3035 
A = [_3035\=b] ;

no

?-solve_constr_hier([[(X=Y,1),(Z\=Y,1),(X=b,1),(Z=b,1)]@strong,[(Y=c,1)]@weak],[[]],A).

X = b 
Y = c 
Z = b 
A = [] ;

X = c 
Y = c 
Z = b 
A = [] ;

no

?-solve_constr_hier([[(X=a,1),(Y=b,1),(Y\=b,1)]@strong],[[X=Y]],A).

X = b 
Y = b 
A = [] ;

X = a 
Y = a 
A = [] ;

no

?-solve_constr_hier([[(X=a,1),(Y=b,2),(Y\=b,1)]@strong],[[X=Y]],A).

X = b 
Y = b 
A = [] ;

no

?-solve_constr_hier([[(X=a,1),(Y=b,1),(Y\=b,1)]@strong,[(Y=b,1)]@prefer],[[X=Y]],A).

X = b 
Y = b 
A = [] ;

no

?-solve_constr_hier([[(X=a,1),(Y=b,1),(Y\=b,1)]@strong,[(Y=c,1)]@prefer],[[X=Y]],A).

X = b 
Y = b 
A = [] ;

X = a 
Y = a 
A = [] ;

no

?-solve_constr_hier([[(X=a,1),(Y=b,2),(Y\=b,1)]@strong,[(Y=b,1)]@prefer],[[X=Y]],A).

X = b 
Y = b 
A = [] ;

no

?-solve_constr_hier([[(X=a,2),(Y=b,1),(Y\=b,1)]@strong,[(Y=b,1)]@prefer],[[X=Y]],A).

X = a 
Y = a 
A = [] ;

no