YES Problem: b(c(a(x1))) -> a(b(a(b(x1)))) b(x1) -> c(c(x1)) a(a(x1)) -> a(c(b(a(x1)))) Proof: DP Processor: DPs: b#(c(a(x1))) -> b#(x1) b#(c(a(x1))) -> a#(b(x1)) b#(c(a(x1))) -> b#(a(b(x1))) b#(c(a(x1))) -> a#(b(a(b(x1)))) a#(a(x1)) -> b#(a(x1)) a#(a(x1)) -> a#(c(b(a(x1)))) TRS: b(c(a(x1))) -> a(b(a(b(x1)))) b(x1) -> c(c(x1)) a(a(x1)) -> a(c(b(a(x1)))) Matrix Interpretation Processor: dim=4 interpretation: [a#](x0) = [1 0 0 1]x0, [b#](x0) = [1 0 0 0]x0, [0 0 0 0] [0 0 0 0] [b](x0) = [0 0 0 0]x0 [1 0 0 0] , [0 0 0 1] [0 0 0 1] [c](x0) = [0 0 0 0]x0 [0 0 0 0] , [0 0 1 0] [0] [0 0 0 0] [0] [a](x0) = [0 0 0 0]x0 + [0] [1 0 0 0] [1] orientation: b#(c(a(x1))) = [1 0 0 0]x1 + [1] >= [1 0 0 0]x1 = b#(x1) b#(c(a(x1))) = [1 0 0 0]x1 + [1] >= [1 0 0 0]x1 = a#(b(x1)) b#(c(a(x1))) = [1 0 0 0]x1 + [1] >= [0] = b#(a(b(x1))) b#(c(a(x1))) = [1 0 0 0]x1 + [1] >= [0] = a#(b(a(b(x1)))) a#(a(x1)) = [1 0 1 0]x1 + [1] >= [0 0 1 0]x1 = b#(a(x1)) a#(a(x1)) = [1 0 1 0]x1 + [1] >= [0 0 1 0]x1 = a#(c(b(a(x1)))) [0 0 0 0] [0] [0] [0 0 0 0] [0] [0] b(c(a(x1))) = [0 0 0 0]x1 + [0] >= [0] = a(b(a(b(x1)))) [1 0 0 0] [1] [1] [0 0 0 0] [0] [0 0 0 0] [0] b(x1) = [0 0 0 0]x1 >= [0] = c(c(x1)) [1 0 0 0] [0] [0 0 0 0] [0] [0 0 0 0] [0] [0 0 0 0] [0] [0 0 0 0] [0] a(a(x1)) = [0 0 0 0]x1 + [0] >= [0 0 0 0]x1 + [0] = a(c(b(a(x1)))) [0 0 1 0] [1] [0 0 1 0] [1] problem: DPs: TRS: b(c(a(x1))) -> a(b(a(b(x1)))) b(x1) -> c(c(x1)) a(a(x1)) -> a(c(b(a(x1)))) Qed