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) = 1x0 + x1 + -8, [c](x0) = 2x0 + 0, [f](x0, x1) = x0 + -1x1, [s](x0) = 2x0 + 0 orientation: f#(s(x),y) = 3x + y + 1 >= 2x + 0 = f#(x,s(x)) f#(x,s(y)) = 1x + 2y + 0 >= x + 1y + -8 = f#(y,x) f#(c(x),y) = 3x + y + 1 >= 2x + 0 = f#(x,s(x)) f(s(x),y) = 2x + -1y + 0 >= 1x + -1 = f(x,s(x)) f(x,s(y)) = x + 1y + -1 >= -1x + y = f(y,x) f(c(x),y) = 2x + -1y + 0 >= 1x + -1 = 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