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