MAYBE
25.17/10.19	MAYBE
25.17/10.19	
25.17/10.19	Problem:
25.17/10.19	 :(x,x) -> e()
25.17/10.19	 :(x,e()) -> x
25.17/10.19	 i(:(x,y)) -> :(y,x)
25.17/10.19	 :(:(x,y),z) -> :(x,:(z,i(y)))
25.17/10.19	 :(e(),x) -> i(x)
25.17/10.19	 i(i(x)) -> x
25.17/10.19	 i(e()) -> e()
25.17/10.19	 :(x,:(y,i(x))) -> i(y)
25.17/10.19	 :(x,:(y,:(i(x),z))) -> :(i(z),y)
25.17/10.19	 :(i(x),:(y,x)) -> i(y)
25.17/10.19	 :(i(x),:(y,:(x,z))) -> :(i(z),y)
25.17/10.19	
25.17/10.19	Proof:
25.17/10.19	 Open
25.30/10.20	EOF