YES (VAR x0 x1 x y z) (RULES f(b(),f(a(),x0)) -> f(a(),f(a(),f(a(),f(a(),f(a(),f(a(),f(a(),f(b(),x0)))))))) i(f(x0,x1)) -> f(i(x1),i(x0)) f(i(x0),f(x0,x1)) -> x1 i(a()) -> f(a(),f(a(),f(a(),f(a(),f(a(),f(a(),a())))))) i(i(x0)) -> x0 i(b()) -> b() f(i(x0),x0) -> f(a(),f(a(),f(a(),f(a(),f(a(),f(a(),f(a(),a()))))))) f(a(),f(a(),f(a(),f(a(),f(a(),f(a(),f(a(),f(a(),x0)))))))) -> x0 f(b(),a()) -> f(a(),f(a(),f(a(),f(a(),f(a(),f(a(),f(a(),b()))))))) f(x1,f(i(x1),x0)) -> x0 f(b(),f(b(),x0)) -> x0 f(x,i(x)) -> f(a(),f(a(),f(a(),f(a(),f(a(),f(a(),f(a(),a()))))))) f(b(),b()) -> f(a(),f(a(),f(a(),f(a(),f(a(),f(a(),f(a(),a()))))))) f(x,f(a(),f(a(),f(a(),f(a(),f(a(),f(a(),f(a(),a())))))))) -> x e() -> f(a(),f(a(),f(a(),f(a(),f(a(),f(a(),f(a(),a()))))))) f(f(x,y),z) -> f(x,f(y,z)) ) (COMMENT Termination is shown by ELPO with interpretations on natural numbers f_A(x1,x2) = x1 + x2 i_A(x1) = x1 e_A = 1 a_A = 0 b_A = 1 f#_A(x1,x2) = x1 i#_A(x1) = 0 e#_A = 0 a#_A = 0 b#_A = 0 and precedence: e > i > f > b > a )