2/*
3
4Somehow these still appeared in operations.pl file
5
6subset([],_).
7subset([E|Sub],Set):-member(E,Set),!,subset(Sub,Set).
8
9intersection([],_,[]).
10intersection([H|L1],L2,[H|L3]):-member(H,L2),!,
11 intersection(L1,L2,L3).
12 intersection([_|L1],L2,L3):-intersection(L1,L2,L3).
13
14flatten([],[]):-!.
15flatten([[]|T],Res):-!,flatten(T,Res).
16flatten([[H1|T1]|T],Res):-!,flatten(T,Res1),!,
17 append([H1|T1],Res1,Res).
18flatten([H|T],[H|Res]):-!,flatten(T,Res).
19*/