trace
domains
    list = symbol*
predicates
    del(symbol,list,list)
    permute(list,list)
clauses
    del(X,[X|L1],L1).
    del(X,[Y|L1],[Y|L2]):-
        del(X,L1,L2).
    permute([],[]).
    permute(L,[X|P]):-
        del(X,L,L1),
        permute(L1,P).


Output : 

Goal: permute([a,b,c],P)

P=["a","b","c"]
P=["a","c","b"]
P=["b","a","c"]
P=["b","c","a"]
P=["c","a","b"]
P=["c","b","a"]
6 Solutions
Goal: