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