YES (VAR x1 x0 x y z) (RULES i(f(x1,x0)) -> f(i(x0),i(x1)) h(i(x0)) -> i(h(x0)) f(i(x0),f(x0,x1)) -> x1 f(i(x0),x0) -> e() h(e()) -> e() i(e()) -> e() i(i(x0)) -> x0 f(e(),x1) -> x1 f(x1,f(i(x1),x0)) -> x0 h(f(x,y)) -> f(h(x),h(y)) f(x,e()) -> x f(x,i(x)) -> e() f(f(x,y),z) -> f(x,f(y,z)) ) (COMMENT Termination is shown by LPO with precedence: h > i > f > e )