(VAR x y) (RULES -(x, 0) -> x -(0, s(y)) -> 0 -(s(x), s(y)) -> -(x, y) lt(x, 0) -> false lt(0, s(y)) -> true lt(s(x), s(y)) -> lt(x, y) if(true, x, y) -> x if(false, x, y) -> y div(x, 0) -> 0 div(0, y) -> 0 div(s(x), s(y)) -> if(lt(x, y), 0, s(div(-(x, y), s(y)))) ) (COMMENT Example 8 in \cite{G96}. )