25.17/15.94	MAYBE
25.17/15.94	
25.17/15.94	Problem:
25.17/15.94	 +(0(),y) -> y
25.17/15.94	 +(s(0()),y) -> s(y)
25.17/15.94	 +(+(x,y),z) -> +(x,+(y,z))
25.17/15.94	 +(x,y) -> +(y,x)
25.17/15.94	 s(s(x)) -> s(x)
25.17/15.94	 s(x) -> s(s(x))
25.17/15.94	
25.17/15.94	Proof:
25.17/15.94	 Open
25.17/15.95	EOF