YES Problem: h(f(x,y)) -> f(y,f(h(h(x)),a())) Proof: DP Processor: DPs: h#(f(x,y)) -> h#(x) h#(f(x,y)) -> h#(h(x)) TRS: h(f(x,y)) -> f(y,f(h(h(x)),a())) Matrix Interpretation Processor: dim=2 usable rules: h(f(x,y)) -> f(y,f(h(h(x)),a())) interpretation: [h#](x0) = [1 0]x0, [0] [a] = [0], [0 1] [h](x0) = [3 0]x0, [1 1] [0 0] [1] [f](x0, x1) = [0 0]x0 + [1 1]x1 + [1] orientation: h#(f(x,y)) = [1 1]x + [1] >= [1 0]x = h#(x) h#(f(x,y)) = [1 1]x + [1] >= [0 1]x = h#(h(x)) [0 0] [1 1] [1] [0 0] [1 1] [1] h(f(x,y)) = [3 3]x + [0 0]y + [3] >= [3 3]x + [0 0]y + [3] = f(y,f(h(h(x)),a())) problem: DPs: TRS: h(f(x,y)) -> f(y,f(h(h(x)),a())) Qed