NO Problem: -(0(),0()) -> 0() -(s(x),0()) -> s(x) -(x,s(y)) -> -(d(x),y) d(s(x)) -> x -(s(x),s(y)) -> -(x,y) -(d(x),y) -> -(x,s(y)) Proof: Matrix Interpretation Processor: dimension: 1 interpretation: [d](x0) = x0 + 4, [s](x0) = x0 + 1, [-](x0, x1) = x0 + 4x1, [0] = 0 orientation: -(0(),0()) = 0 >= 0 = 0() -(s(x),0()) = x + 1 >= x + 1 = s(x) -(x,s(y)) = x + 4y + 4 >= x + 4y + 4 = -(d(x),y) d(s(x)) = x + 5 >= x = x -(s(x),s(y)) = x + 4y + 5 >= x + 4y = -(x,y) -(d(x),y) = x + 4y + 4 >= x + 4y + 4 = -(x,s(y)) problem: -(0(),0()) -> 0() -(s(x),0()) -> s(x) -(x,s(y)) -> -(d(x),y) -(d(x),y) -> -(x,s(y)) Matrix Interpretation Processor: dimension: 1 interpretation: [d](x0) = x0 + 2, [s](x0) = x0 + 4, [-](x0, x1) = 4x0 + 2x1, [0] = 0 orientation: -(0(),0()) = 0 >= 0 = 0() -(s(x),0()) = 4x + 16 >= x + 4 = s(x) -(x,s(y)) = 4x + 2y + 8 >= 4x + 2y + 8 = -(d(x),y) -(d(x),y) = 4x + 2y + 8 >= 4x + 2y + 8 = -(x,s(y)) problem: -(0(),0()) -> 0() -(x,s(y)) -> -(d(x),y) -(d(x),y) -> -(x,s(y)) Matrix Interpretation Processor: dimension: 1 interpretation: [d](x0) = x0, [s](x0) = x0, [-](x0, x1) = x0 + x1, [0] = 2 orientation: -(0(),0()) = 4 >= 2 = 0() -(x,s(y)) = x + y >= x + y = -(d(x),y) -(d(x),y) = x + y >= x + y = -(x,s(y)) problem: -(x,s(y)) -> -(d(x),y) -(d(x),y) -> -(x,s(y)) Unfolding Processor: loop length: 2 terms: -(x4,s(x5)) -(d(x4),x5) context: [] substitution: x4 -> x4 x5 -> x5 Qed