YES Problem: f(f(x)) -> f(g(f(x),x)) f(f(x)) -> f(h(f(x),f(x))) g(x,y) -> y h(x,x) -> g(x,0()) Proof: DP Processor: DPs: f#(f(x)) -> g#(f(x),x) f#(f(x)) -> f#(g(f(x),x)) f#(f(x)) -> h#(f(x),f(x)) f#(f(x)) -> f#(h(f(x),f(x))) h#(x,x) -> g#(x,0()) TRS: f(f(x)) -> f(g(f(x),x)) f(f(x)) -> f(h(f(x),f(x))) g(x,y) -> y h(x,x) -> g(x,0()) Arctic Interpretation Processor: dimension: 1 interpretation: [h#](x0, x1) = 1x0 + 4, [g#](x0, x1) = 1x1, [f#](x0) = 2x0 + 0, [0] = 0, [h](x0, x1) = 4, [g](x0, x1) = 1x1 + 0, [f](x0) = 2x0 + 5 orientation: f#(f(x)) = 4x + 7 >= 1x = g#(f(x),x) f#(f(x)) = 4x + 7 >= 3x + 2 = f#(g(f(x),x)) f#(f(x)) = 4x + 7 >= 3x + 6 = h#(f(x),f(x)) f#(f(x)) = 4x + 7 >= 6 = f#(h(f(x),f(x))) h#(x,x) = 1x + 4 >= 1 = g#(x,0()) f(f(x)) = 4x + 7 >= 3x + 5 = f(g(f(x),x)) f(f(x)) = 4x + 7 >= 6 = f(h(f(x),f(x))) g(x,y) = 1y + 0 >= y = y h(x,x) = 4 >= 1 = g(x,0()) problem: DPs: TRS: f(f(x)) -> f(g(f(x),x)) f(f(x)) -> f(h(f(x),f(x))) g(x,y) -> y h(x,x) -> g(x,0()) Qed