MAYBE
28.35/10.18	MAYBE
28.35/10.19	
28.35/10.19	Problem:
28.35/10.19	 minus(0()) -> 0()
28.35/10.19	 +(x,0()) -> x
28.35/10.19	 +(0(),y) -> y
28.35/10.19	 +(minus(1()),1()) -> 0()
28.35/10.19	 minus(minus(x)) -> x
28.35/10.19	 +(x,minus(y)) -> minus(+(minus(x),y))
28.35/10.19	 +(x,+(y,z)) -> +(+(x,y),z)
28.35/10.19	 +(minus(+(x,1())),1()) -> minus(x)
28.35/10.19	
28.35/10.19	Proof:
28.35/10.19	 Open
28.35/10.19	EOF