%% traverse(+Antecedent,+Consequent,+List)
%% Checks an argument is valid, or proven by parts given
%% An argument is given by If <Antecedent>, then <Consequent>
%% List is a list of reasons for the argument

%% ?- traverse(a,b,[[a,c],[c,b]],_).
%% ?- traverse(a,b,[[a,c],[c,b],[a,d],[d,c]],_).

traverse(A,B,List) :-
	traverse1(A,B,List,_).

%% traverse(+Antecedent,+Consequent,+List,-List)
%% Most of the variables are the same as for traverse/3
%% List2 is List with all the found reasons removed

traverse1(_,_,[],[]).
traverse1(A,B,List,List4) :- 
	delete(List,[A,C],List1), delete(List1,[C,B],List2),
	traverse1(A,C,List2,List3), traverse1(C,B,List3,List4).