YES Problem: strict: n(s(x1)) -> s(x1) o(s(x1)) -> s(x1) n(o(p(x1))) -> o(n(x1)) weak: t(x1) -> t(c(n(x1))) p(s(x1)) -> s(x1) o(n(x1)) -> n(o(x1)) p(n(x1)) -> m(p(x1)) p(m(x1)) -> m(p(x1)) o(m(x1)) -> n(o(x1)) n(p(x1)) -> p(n(x1)) c(p(x1)) -> p(c(x1)) c(m(x1)) -> m(c(x1)) c(n(x1)) -> n(c(x1)) c(o(x1)) -> o(c(x1)) c(o(x1)) -> o(x1) Proof: String Reversal Processor: strict: s(n(x1)) -> s(x1) s(o(x1)) -> s(x1) p(o(n(x1))) -> n(o(x1)) weak: t(x1) -> n(c(t(x1))) s(p(x1)) -> s(x1) n(o(x1)) -> o(n(x1)) n(p(x1)) -> p(m(x1)) m(p(x1)) -> p(m(x1)) m(o(x1)) -> o(n(x1)) p(n(x1)) -> n(p(x1)) p(c(x1)) -> c(p(x1)) m(c(x1)) -> c(m(x1)) n(c(x1)) -> c(n(x1)) o(c(x1)) -> c(o(x1)) o(c(x1)) -> o(x1) Arctic Interpretation Processor: dimension: 1 interpretation: [t](x0) = x0, [n](x0) = x0, [p](x0) = 4x0, [c](x0) = x0, [s](x0) = x0, [m](x0) = x0, [o](x0) = 8x0 orientation: s(n(x1)) = x1 >= x1 = s(x1) s(o(x1)) = 8x1 >= x1 = s(x1) p(o(n(x1))) = 12x1 >= 8x1 = n(o(x1)) t(x1) = x1 >= x1 = n(c(t(x1))) s(p(x1)) = 4x1 >= x1 = s(x1) n(o(x1)) = 8x1 >= 8x1 = o(n(x1)) n(p(x1)) = 4x1 >= 4x1 = p(m(x1)) m(p(x1)) = 4x1 >= 4x1 = p(m(x1)) m(o(x1)) = 8x1 >= 8x1 = o(n(x1)) p(n(x1)) = 4x1 >= 4x1 = n(p(x1)) p(c(x1)) = 4x1 >= 4x1 = c(p(x1)) m(c(x1)) = x1 >= x1 = c(m(x1)) n(c(x1)) = x1 >= x1 = c(n(x1)) o(c(x1)) = 8x1 >= 8x1 = c(o(x1)) o(c(x1)) = 8x1 >= 8x1 = o(x1) problem: strict: s(n(x1)) -> s(x1) weak: t(x1) -> n(c(t(x1))) n(o(x1)) -> o(n(x1)) n(p(x1)) -> p(m(x1)) m(p(x1)) -> p(m(x1)) m(o(x1)) -> o(n(x1)) p(n(x1)) -> n(p(x1)) p(c(x1)) -> c(p(x1)) m(c(x1)) -> c(m(x1)) n(c(x1)) -> c(n(x1)) o(c(x1)) -> c(o(x1)) o(c(x1)) -> o(x1) Matrix Interpretation Processor: dim=2 interpretation: [2 0] [1] [t](x0) = [2 2]x0 + [2], [0] [n](x0) = x0 + [1], [2 0] [p](x0) = [0 1]x0, [1 0] [c](x0) = [0 0]x0, [2 1] [2] [s](x0) = [0 0]x0 + [0], [0] [m](x0) = x0 + [1], [2 0] [0] [o](x0) = [0 0]x0 + [2] orientation: [2 1] [3] [2 1] [2] s(n(x1)) = [0 0]x1 + [0] >= [0 0]x1 + [0] = s(x1) [2 0] [1] [2 0] [1] t(x1) = [2 2]x1 + [2] >= [0 0]x1 + [1] = n(c(t(x1))) [2 0] [0] [2 0] [0] n(o(x1)) = [0 0]x1 + [3] >= [0 0]x1 + [2] = o(n(x1)) [2 0] [0] [2 0] [0] n(p(x1)) = [0 1]x1 + [1] >= [0 1]x1 + [1] = p(m(x1)) [2 0] [0] [2 0] [0] m(p(x1)) = [0 1]x1 + [1] >= [0 1]x1 + [1] = p(m(x1)) [2 0] [0] [2 0] [0] m(o(x1)) = [0 0]x1 + [3] >= [0 0]x1 + [2] = o(n(x1)) [2 0] [0] [2 0] [0] p(n(x1)) = [0 1]x1 + [1] >= [0 1]x1 + [1] = n(p(x1)) [2 0] [2 0] p(c(x1)) = [0 0]x1 >= [0 0]x1 = c(p(x1)) [1 0] [0] [1 0] m(c(x1)) = [0 0]x1 + [1] >= [0 0]x1 = c(m(x1)) [1 0] [0] [1 0] n(c(x1)) = [0 0]x1 + [1] >= [0 0]x1 = c(n(x1)) [2 0] [0] [2 0] o(c(x1)) = [0 0]x1 + [2] >= [0 0]x1 = c(o(x1)) [2 0] [0] [2 0] [0] o(c(x1)) = [0 0]x1 + [2] >= [0 0]x1 + [2] = o(x1) problem: strict: weak: t(x1) -> n(c(t(x1))) n(o(x1)) -> o(n(x1)) n(p(x1)) -> p(m(x1)) m(p(x1)) -> p(m(x1)) m(o(x1)) -> o(n(x1)) p(n(x1)) -> n(p(x1)) p(c(x1)) -> c(p(x1)) m(c(x1)) -> c(m(x1)) n(c(x1)) -> c(n(x1)) o(c(x1)) -> c(o(x1)) o(c(x1)) -> o(x1) Qed