YES Problem: f(s(x),y) -> f(x,s(x)) f(x,s(y)) -> f(y,x) f(c(x),y) -> f(x,s(x)) Proof: DP Processor: DPs: f#(s(x),y) -> f#(x,s(x)) f#(x,s(y)) -> f#(y,x) f#(c(x),y) -> f#(x,s(x)) TRS: f(s(x),y) -> f(x,s(x)) f(x,s(y)) -> f(y,x) f(c(x),y) -> f(x,s(x)) Arctic Interpretation Processor: dimension: 1 interpretation: [f#](x0, x1) = x0 + x1 + -16, [c](x0) = 1x0 + 4, [f](x0, x1) = 0, [s](x0) = x0 orientation: f#(s(x),y) = x + y + -16 >= x + -16 = f#(x,s(x)) f#(x,s(y)) = x + y + -16 >= x + y + -16 = f#(y,x) f#(c(x),y) = 1x + y + 4 >= x + -16 = f#(x,s(x)) f(s(x),y) = 0 >= 0 = f(x,s(x)) f(x,s(y)) = 0 >= 0 = f(y,x) f(c(x),y) = 0 >= 0 = f(x,s(x)) problem: DPs: f#(s(x),y) -> f#(x,s(x)) f#(x,s(y)) -> f#(y,x) TRS: f(s(x),y) -> f(x,s(x)) f(x,s(y)) -> f(y,x) f(c(x),y) -> f(x,s(x)) Arctic Interpretation Processor: dimension: 1 interpretation: [f#](x0, x1) = 1x0 + x1, [c](x0) = 1x0 + -11, [f](x0, x1) = 3x0 + 2x1, [s](x0) = 2x0 orientation: f#(s(x),y) = 3x + y >= 2x = f#(x,s(x)) f#(x,s(y)) = 1x + 2y >= x + 1y = f#(y,x) f(s(x),y) = 5x + 2y >= 4x = f(x,s(x)) f(x,s(y)) = 3x + 4y >= 2x + 3y = f(y,x) f(c(x),y) = 4x + 2y + -8 >= 4x = f(x,s(x)) problem: DPs: TRS: f(s(x),y) -> f(x,s(x)) f(x,s(y)) -> f(y,x) f(c(x),y) -> f(x,s(x)) Qed