YES Problem: f(f(X)) -> c(n__f(g(n__f(X)))) c(X) -> d(activate(X)) h(X) -> c(n__d(X)) f(X) -> n__f(X) d(X) -> n__d(X) activate(n__f(X)) -> f(X) activate(n__d(X)) -> d(X) activate(X) -> X Proof: WPO Processor: algebra: Sum weight function: w0 = 0 w(h) = 2 w(activate) = w(c) = w(f) = 1 w(n__d) = w(d) = w(g) = w(n__f) = 0 status function: st(n__d) = st(h) = st(d) = st(activate) = st(c) = st(g) = st(n__f) = st(f) = [0] precedence: c > d ~ activate > n__d ~ h ~ g ~ n__f ~ f problem: Qed