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