0 QTRS
leq(0, y) → true leq(s(x), 0) → false leq(s(x), s(y)) → leq(x, y) if(true, x, y) → x if(false, x, y) → y -(x, 0) → x -(s(x), s(y)) → -(x, y) mod(0, y) → 0 mod(s(x), 0) → 0 mod(s(x), s(y)) → if(leq(y, x), mod(-(s(x), s(y)), s(y)), s(x))