dislikes(sam, onions). 
dislikes(sam, greenpeppers). 
dislikes(parker, pepperoni). 
dislikes(parker, greenpeppers). 
dislikes(elizabeth, pepperoni). 
dislikes(elizabeth, eggplant). 
dislikes(fred, pepperoni).

dislikes_with_isno(Name, Topping, IsNo) :-
	dislikes(Name, Topping).

dislikes_topping([H|T], Top, IsNo) :- 
	dislikes_with_isno(H, Top, IsNo),
	dislikes_topping(T, Top, IsNo).