YES Problem: f(x,y) -> g1(x,x,y) f(x,y) -> g1(y,x,x) f(x,y) -> g2(x,y,y) f(x,y) -> g2(y,y,x) g1(x,x,y) -> h(x,y) g1(y,x,x) -> h(x,y) g2(x,y,y) -> h(x,y) g2(y,y,x) -> h(x,y) h(x,x) -> x Proof: Polynomial Interpretation Processor: dimension: 1 interpretation: [h](x0, x1) = x0 + x1 + 2, [g2](x0, x1, x2) = 3x0 + 2x1 + 3x2 + 4, [g1](x0, x1, x2) = x0 + 2x1 + x2 + 4, [f](x0, x1) = 3x0 + 5x1 + 5 orientation: f(x,y) = 3x + 5y + 5 >= 3x + y + 4 = g1(x,x,y) f(x,y) = 3x + 5y + 5 >= 3x + y + 4 = g1(y,x,x) f(x,y) = 3x + 5y + 5 >= 3x + 5y + 4 = g2(x,y,y) f(x,y) = 3x + 5y + 5 >= 3x + 5y + 4 = g2(y,y,x) g1(x,x,y) = 3x + y + 4 >= x + y + 2 = h(x,y) g1(y,x,x) = 3x + y + 4 >= x + y + 2 = h(x,y) g2(x,y,y) = 3x + 5y + 4 >= x + y + 2 = h(x,y) g2(y,y,x) = 3x + 5y + 4 >= x + y + 2 = h(x,y) h(x,x) = 2x + 2 >= x = x problem: Qed