YES (VAR x2 x0 x1 x y) (RULES *(*(x2,x0),x1) -> *(f(x0),x1) *(x0,f(x1)) -> *(x0,x1) g(*(x1,x0)) -> f(x0) f(*(x0,x1)) -> g(x0) *(x0,*(x1,x2)) -> *(x0,g(x1)) f(f(x0)) -> f(x0) *(f(x),x) -> f(x) g(f(x0)) -> f(x0) f(g(x0)) -> g(x0) *(x0,g(x0)) -> g(x0) g(g(x0)) -> g(x0) *(f(x0),g(x0)) -> x0 *(g(x),y) -> *(x,y) ) (COMMENT Termination is shown by KBO with weight w0 = 2 w(*) = 0 w(f) = 1 w(g) = 1 and precedence: * > f > g )