Hi group,

I need to define the relation double(Xs, Ys) where Ys is the bouble Xs list

Example: double([a, b, c], [a, a, b, b, c, c ]) is true

can anyone help me......

Ty for ur help,
PM

but it's evident !!

double([],[]).
double([X|L],[X,X|L2]):-double(L,L2).

Thank you for your help !

C ya