(from AG01 3.8b) (VAR x y) (RULES le(0,y) -> true le(s(x),0) -> false le(s(x),s(y)) -> le(x,y) minus(0,y) -> 0 minus(s(x),y) -> if_minus(le(s(x),y),s(x),y) if_minus(true,s(x),y) -> 0 if_minus(false,s(x),y) -> s(minus(x,y)) quot(0,s(y)) -> 0 quot(s(x),s(y)) -> s(quot(minus(x,y),s(y))) log(s(0)) -> 0 log(s(s(x))) -> s(log(s(quot(x,s(s(0)))))) )