YES Problem: f(c(a(),z,x)) -> b(a(),z) b(x,b(z,y)) -> f(b(f(f(z)),c(x,z,y))) b(y,z) -> z Proof: DP Processor: DPs: f#(c(a(),z,x)) -> b#(a(),z) b#(x,b(z,y)) -> f#(z) b#(x,b(z,y)) -> f#(f(z)) b#(x,b(z,y)) -> b#(f(f(z)),c(x,z,y)) b#(x,b(z,y)) -> f#(b(f(f(z)),c(x,z,y))) TRS: f(c(a(),z,x)) -> b(a(),z) b(x,b(z,y)) -> f(b(f(f(z)),c(x,z,y))) b(y,z) -> z Matrix Interpretation Processor: dim=2 usable rules: f(c(a(),z,x)) -> b(a(),z) b(x,b(z,y)) -> f(b(f(f(z)),c(x,z,y))) b(y,z) -> z interpretation: [b#](x0, x1) = [2 1]x1 + [1], [f#](x0) = [1 0]x0 + [2], [3 0] [2 1] [0] [b](x0, x1) = [1 2]x0 + [2 1]x1 + [2], [1 0] [0] [f](x0) = [1 0]x0 + [2], [2 1] [3 0] [c](x0, x1, x2) = [0 0]x1 + [0 2]x2, [0] [a] = [0] orientation: f#(c(a(),z,x)) = [3 0]x + [2 1]z + [2] >= [2 1]z + [1] = b#(a(),z) b#(x,b(z,y)) = [6 3]y + [7 2]z + [3] >= [1 0]z + [2] = f#(z) b#(x,b(z,y)) = [6 3]y + [7 2]z + [3] >= [1 0]z + [2] = f#(f(z)) b#(x,b(z,y)) = [6 3]y + [7 2]z + [3] >= [6 2]y + [4 2]z + [1] = b#(f(f(z)),c(x,z,y)) b#(x,b(z,y)) = [6 3]y + [7 2]z + [3] >= [6 2]y + [7 2]z + [2] = f#(b(f(f(z)),c(x,z,y))) [3 0] [2 1] [0] [2 1] [0] f(c(a(),z,x)) = [3 0]x + [2 1]z + [2] >= [2 1]z + [2] = b(a(),z) [3 0] [6 3] [7 2] [2] [6 2] [7 2] [0] b(x,b(z,y)) = [1 2]x + [6 3]y + [7 2]z + [4] >= [6 2]y + [7 2]z + [2] = f(b(f(f(z)),c(x,z,y))) [3 0] [2 1] [0] b(y,z) = [1 2]y + [2 1]z + [2] >= z = z problem: DPs: TRS: f(c(a(),z,x)) -> b(a(),z) b(x,b(z,y)) -> f(b(f(f(z)),c(x,z,y))) b(y,z) -> z Qed