700.41/299.38	MAYBE
700.41/299.38	
700.41/299.38	Problem:
700.41/299.38	 strict:
700.41/299.38	  p(0(),y) -> y
700.41/299.38	  p(s(x),y) -> s(p(x,y))
700.41/299.38	 weak:
700.41/299.38	  p(x,y) -> s(p(x,y))
700.41/299.38	
700.41/299.38	Proof:
700.41/299.38	 Open
700.41/299.38	EOF