YES(?,O(n^2)) Problem: +(0(),y) -> y +(s(x),y) -> s(+(x,y)) +(s(x),y) -> +(x,s(y)) Proof: RT Transformation Processor: strict: +(0(),y) -> y +(s(x),y) -> s(+(x,y)) +(s(x),y) -> +(x,s(y)) weak: Matrix Interpretation Processor: dimension: 1 interpretation: [s](x0) = x0 + 4, [+](x0, x1) = x0 + x1 + 29, [0] = 2 orientation: +(0(),y) = y + 31 >= y = y +(s(x),y) = x + y + 33 >= x + y + 33 = s(+(x,y)) +(s(x),y) = x + y + 33 >= x + y + 33 = +(x,s(y)) problem: strict: +(s(x),y) -> s(+(x,y)) +(s(x),y) -> +(x,s(y)) weak: +(0(),y) -> y Matrix Interpretation Processor: dimension: 2 interpretation: [0] [s](x0) = x0 + [1], [1 1] [1 1] [+](x0, x1) = [0 1]x0 + [0 1]x1, [0] [0] = [0] orientation: [1 1] [1 1] [1] [1 1] [1 1] [0] +(s(x),y) = [0 1]x + [0 1]y + [1] >= [0 1]x + [0 1]y + [1] = s(+(x,y)) [1 1] [1 1] [1] [1 1] [1 1] [1] +(s(x),y) = [0 1]x + [0 1]y + [1] >= [0 1]x + [0 1]y + [1] = +(x,s(y)) [1 1] +(0(),y) = [0 1]y >= y = y problem: strict: +(s(x),y) -> +(x,s(y)) weak: +(s(x),y) -> s(+(x,y)) +(0(),y) -> y Matrix Interpretation Processor: dimension: 2 interpretation: [0] [s](x0) = x0 + [1], [1 1] [+](x0, x1) = [0 1]x0 + x1, [0] [0] = [0] orientation: [1 1] [1] [1 1] [0] +(s(x),y) = [0 1]x + y + [1] >= [0 1]x + y + [1] = +(x,s(y)) [1 1] [1] [1 1] [0] +(s(x),y) = [0 1]x + y + [1] >= [0 1]x + y + [1] = s(+(x,y)) +(0(),y) = y >= y = y problem: strict: weak: +(s(x),y) -> +(x,s(y)) +(s(x),y) -> s(+(x,y)) +(0(),y) -> y Qed