(VAR x y ) (RULES p(0) -> 0 p(s(x)) -> x minus(x, 0) -> x minus(s(x), s(y)) -> minus(x, y) minus(x, s(y)) -> p(minus(x, y)) div(0, s(y)) -> 0 div(s(x), s(y)) -> s(div(minus(s(x), s(y)), s(y))) log(s(0), s(s(y))) -> 0 log(s(s(x)), s(s(y))) -> s(log(div(minus(x, y), s(s(y))), s(s(y)))) )