YES (VAR x0 x) (RULES u(v(v(x0))) -> v(v(u(x0))) c(u(u(x0))) -> u(u(c(x0))) c(u(v(x0))) -> b(b(u(u(v(c(u(x0))))))) u(b(x0)) -> b(b(u(v(x0)))) c(b(x0)) -> v(c(x0)) c(u(c(x0))) -> u(x0) u(v(u(x0))) -> v(x0) a(x0) -> b(u(v(x0))) w(x0) -> b(u(v(c(u(x0))))) v(b(x)) -> x b(v(x)) -> x c(v(x)) -> b(c(x)) ) (COMMENT Termination is shown by LPO with precedence: w > a > c > u > b > v )