MAYBE
179.00/58.79	MAYBE
179.00/58.79	
179.00/58.79	Problem:
179.00/58.79	 active(f(X,X)) -> mark(f(a(),b()))
179.00/58.79	 active(b()) -> mark(a())
179.00/58.79	 mark(f(X1,X2)) -> active(f(mark(X1),X2))
179.00/58.79	 mark(a()) -> active(a())
179.00/58.79	 mark(b()) -> active(b())
179.00/58.79	 f(mark(X1),X2) -> f(X1,X2)
179.00/58.79	 f(X1,mark(X2)) -> f(X1,X2)
179.00/58.79	 f(active(X1),X2) -> f(X1,X2)
179.00/58.79	 f(X1,active(X2)) -> f(X1,X2)
179.00/58.79	
179.00/58.79	Proof:
179.00/58.79	 Open
179.00/58.80	EOF