YES (THEORY (AC + * ) ) (VAR x2 x1 x3 x y z ) (RULES *(x2,+(x1,x3)) -> +(*(x1,x2) ,*(x3,x2)) *(x2,s(x1)) -> +(*(x1,x2),x2) +(x2,s(x1)) -> s(+(x1,x2)) -(s(x),s(y)) -> -(x,y) *(zero(),x) -> zero() +(zero(),x) -> x -(zero(),x) -> zero() -(x,zero()) -> x +(x1,zero()) -> x1 *(x1,zero()) -> zero() +(s(x),y) -> s(+(x,y)) *(s(x),y) -> +(*(x,y),y) *(+(x,y),z) -> +(*(x,z),*(y,z)) )