YES Problem: p(0(x1)) -> s(s(0(s(s(p(x1)))))) p(s(0(x1))) -> 0(x1) p(s(s(x1))) -> s(p(s(x1))) f(s(x1)) -> g(q(i(x1))) g(x1) -> f(p(p(x1))) q(i(x1)) -> q(s(x1)) q(s(x1)) -> s(s(x1)) i(x1) -> s(x1) Proof: Matrix Interpretation Processor: dim=4 interpretation: [1 0 0 0] [0 1 1 0] [i](x0) = [0 0 0 0]x0 [1 0 0 0] , [1 0 0 1] [0] [1 0 0 0] [1] [p](x0) = [1 0 0 0]x0 + [1] [0 1 0 0] [0], [1 0 0 0] [0] [0 0 0 0] [0] [f](x0) = [0 0 0 0]x0 + [1] [1 0 0 0] [0], [1 0 0 0] [0 0 0 0] [q](x0) = [0 0 0 1]x0 [0 0 0 0] , [1 0 0 1] [0] [0 0 0 0] [0] [0](x0) = [0 0 0 0]x0 + [1] [0 0 0 0] [1], [1 1 0 1] [0] [0 0 0 0] [0] [g](x0) = [0 0 0 1]x0 + [1] [1 1 0 1] [0], [1 0 0 0] [0 0 1 0] [s](x0) = [0 0 0 0]x0 [0 0 0 0] orientation: [1 0 0 1] [1] [1 0 0 1] [1 0 0 1] [1] [0 0 0 0] p(0(x1)) = [1 0 0 1]x1 + [1] >= [0 0 0 0]x1 = s(s(0(s(s(p(x1)))))) [0 0 0 0] [0] [0 0 0 0] [1 0 0 1] [0] [1 0 0 1] [0] [1 0 0 1] [1] [0 0 0 0] [0] p(s(0(x1))) = [1 0 0 1]x1 + [1] >= [0 0 0 0]x1 + [1] = 0(x1) [0 0 0 0] [1] [0 0 0 0] [1] [1 0 0 0] [0] [1 0 0 0] [0] [1 0 0 0] [1] [1 0 0 0] [1] p(s(s(x1))) = [1 0 0 0]x1 + [1] >= [0 0 0 0]x1 + [0] = s(p(s(x1))) [0 0 0 0] [0] [0 0 0 0] [0] [1 0 0 0] [0] [1 0 0 0] [0] [0 0 0 0] [0] [0 0 0 0] [0] f(s(x1)) = [0 0 0 0]x1 + [1] >= [0 0 0 0]x1 + [1] = g(q(i(x1))) [1 0 0 0] [0] [1 0 0 0] [0] [1 1 0 1] [0] [1 1 0 1] [0] [0 0 0 0] [0] [0 0 0 0] [0] g(x1) = [0 0 0 1]x1 + [1] >= [0 0 0 0]x1 + [1] = f(p(p(x1))) [1 1 0 1] [0] [1 1 0 1] [0] [1 0 0 0] [1 0 0 0] [0 0 0 0] [0 0 0 0] q(i(x1)) = [1 0 0 0]x1 >= [0 0 0 0]x1 = q(s(x1)) [0 0 0 0] [0 0 0 0] [1 0 0 0] [1 0 0 0] [0 0 0 0] [0 0 0 0] q(s(x1)) = [0 0 0 0]x1 >= [0 0 0 0]x1 = s(s(x1)) [0 0 0 0] [0 0 0 0] [1 0 0 0] [1 0 0 0] [0 1 1 0] [0 0 1 0] i(x1) = [0 0 0 0]x1 >= [0 0 0 0]x1 = s(x1) [1 0 0 0] [0 0 0 0] problem: p(s(0(x1))) -> 0(x1) p(s(s(x1))) -> s(p(s(x1))) f(s(x1)) -> g(q(i(x1))) g(x1) -> f(p(p(x1))) q(i(x1)) -> q(s(x1)) q(s(x1)) -> s(s(x1)) i(x1) -> s(x1) Matrix Interpretation Processor: dim=4 interpretation: [1 0 0 1] [0] [0 1 0 1] [1] [i](x0) = [1 0 0 1]x0 + [0] [0 1 0 0] [0], [1 0 0 0] [0 0 0 1] [p](x0) = [0 0 0 1]x0 [0 0 1 0] , [1 1 0 0] [0] [1 1 0 0] [1] [f](x0) = [0 0 0 0]x0 + [0] [0 1 0 0] [1], [1 0 0 0] [0] [0 1 0 1] [1] [q](x0) = [0 0 0 1]x0 + [0] [0 1 1 0] [0], [1 1 0 1] [1 1 0 0] [0](x0) = [0 0 0 0]x0 [0 0 0 0] , [1 0 1 0] [1] [1 0 1 0] [1] [g](x0) = [0 0 0 0]x0 + [0] [0 0 1 0] [1], [1 0 0 0] [0] [0 1 0 1] [1] [s](x0) = [0 0 0 1]x0 + [0] [0 1 0 0] [0] orientation: [1 1 0 1] [1 1 0 1] [1 1 0 0] [1 1 0 0] p(s(0(x1))) = [1 1 0 0]x1 >= [0 0 0 0]x1 = 0(x1) [0 0 0 0] [0 0 0 0] [1 0 0 0] [0] [1 0 0 0] [0] [0 1 0 1] [1] [0 1 0 1] [1] p(s(s(x1))) = [0 1 0 1]x1 + [1] >= [0 0 0 1]x1 + [0] = s(p(s(x1))) [0 1 0 0] [0] [0 1 0 0] [0] [1 1 0 1] [1] [1 1 0 1] [1] [1 1 0 1] [2] [1 1 0 1] [1] f(s(x1)) = [0 0 0 0]x1 + [0] >= [0 0 0 0]x1 + [0] = g(q(i(x1))) [0 1 0 1] [2] [0 1 0 0] [1] [1 0 1 0] [1] [1 0 1 0] [0] [1 0 1 0] [1] [1 0 1 0] [1] g(x1) = [0 0 0 0]x1 + [0] >= [0 0 0 0]x1 + [0] = f(p(p(x1))) [0 0 1 0] [1] [0 0 1 0] [1] [1 0 0 1] [0] [1 0 0 0] [0] [0 2 0 1] [2] [0 2 0 1] [2] q(i(x1)) = [0 1 0 0]x1 + [0] >= [0 1 0 0]x1 + [0] = q(s(x1)) [1 1 0 2] [1] [0 1 0 2] [1] [1 0 0 0] [0] [1 0 0 0] [0] [0 2 0 1] [2] [0 2 0 1] [2] q(s(x1)) = [0 1 0 0]x1 + [0] >= [0 1 0 0]x1 + [0] = s(s(x1)) [0 1 0 2] [1] [0 1 0 1] [1] [1 0 0 1] [0] [1 0 0 0] [0] [0 1 0 1] [1] [0 1 0 1] [1] i(x1) = [1 0 0 1]x1 + [0] >= [0 0 0 1]x1 + [0] = s(x1) [0 1 0 0] [0] [0 1 0 0] [0] problem: p(s(0(x1))) -> 0(x1) p(s(s(x1))) -> s(p(s(x1))) f(s(x1)) -> g(q(i(x1))) q(i(x1)) -> q(s(x1)) q(s(x1)) -> s(s(x1)) i(x1) -> s(x1) String Reversal Processor: 0(s(p(x1))) -> 0(x1) s(s(p(x1))) -> s(p(s(x1))) s(f(x1)) -> i(q(g(x1))) i(q(x1)) -> s(q(x1)) s(q(x1)) -> s(s(x1)) i(x1) -> s(x1) WPO Processor: algebra: Sum weight function: w0 = 0 w(f) = 5 w(i) = 4 w(q) = w(s) = w(p) = 2 w(0) = 1 w(g) = 0 status function: st(g) = st(q) = st(i) = st(f) = st(s) = st(p) = st(0) = [0] precedence: q > s > g ~ i ~ f ~ p ~ 0 problem: Qed