0 QTRS
-(x, 0) → x -(s(x), s(y)) → -(x, y) +(0, y) → y +(s(x), y) → s(+(x, y)) *(x, 0) → 0 *(x, s(y)) → +(x, *(x, y)) f(s(x), y) → f(-(*(s(x), s(y)), s(*(s(x), y))), *(y, y))