YES
(VAR x y z)
(RULES
+(x,-(x)) -> 0()
+(x,+(-(x),y)) -> y
+(-(x),x) -> 0()
-(+(x,y)) -> +(-(y),-(x))
g(x,y) -> f(x,+(x,-(y)),y)
+(-(x),+(x,y)) -> y
-(0()) -> 0()
+(0(),x) -> x
+(x,0()) -> x
-(-(x)) -> x
+(+(x,y),z) -> +(x,+(y,z))
f(0(),x,y) -> x
)