YES Problem: b(a(a(x1))) -> a(b(c(x1))) c(a(x1)) -> a(c(x1)) c(b(x1)) -> b(a(x1)) a(a(x1)) -> a(b(a(x1))) Proof: DP Processor: DPs: b#(a(a(x1))) -> c#(x1) b#(a(a(x1))) -> b#(c(x1)) b#(a(a(x1))) -> a#(b(c(x1))) c#(a(x1)) -> c#(x1) c#(a(x1)) -> a#(c(x1)) c#(b(x1)) -> a#(x1) c#(b(x1)) -> b#(a(x1)) a#(a(x1)) -> b#(a(x1)) a#(a(x1)) -> a#(b(a(x1))) TRS: b(a(a(x1))) -> a(b(c(x1))) c(a(x1)) -> a(c(x1)) c(b(x1)) -> b(a(x1)) a(a(x1)) -> a(b(a(x1))) Matrix Interpretation Processor: dim=1 usable rules: b(a(a(x1))) -> a(b(c(x1))) c(a(x1)) -> a(c(x1)) c(b(x1)) -> b(a(x1)) a(a(x1)) -> a(b(a(x1))) interpretation: [a#](x0) = 1/2x0 + 2, [c#](x0) = 2x0 + 5/2, [b#](x0) = 1/2x0 + 3/2, [c](x0) = 2x0 + 1/2, [b](x0) = 1/2x0, [a](x0) = 2x0 + 1 orientation: b#(a(a(x1))) = 2x1 + 3 >= 2x1 + 5/2 = c#(x1) b#(a(a(x1))) = 2x1 + 3 >= x1 + 7/4 = b#(c(x1)) b#(a(a(x1))) = 2x1 + 3 >= 1/2x1 + 17/8 = a#(b(c(x1))) c#(a(x1)) = 4x1 + 9/2 >= 2x1 + 5/2 = c#(x1) c#(a(x1)) = 4x1 + 9/2 >= x1 + 9/4 = a#(c(x1)) c#(b(x1)) = x1 + 5/2 >= 1/2x1 + 2 = a#(x1) c#(b(x1)) = x1 + 5/2 >= x1 + 2 = b#(a(x1)) a#(a(x1)) = x1 + 5/2 >= x1 + 2 = b#(a(x1)) a#(a(x1)) = x1 + 5/2 >= 1/2x1 + 9/4 = a#(b(a(x1))) b(a(a(x1))) = 2x1 + 3/2 >= 2x1 + 3/2 = a(b(c(x1))) c(a(x1)) = 4x1 + 5/2 >= 4x1 + 2 = a(c(x1)) c(b(x1)) = x1 + 1/2 >= x1 + 1/2 = b(a(x1)) a(a(x1)) = 4x1 + 3 >= 2x1 + 2 = a(b(a(x1))) problem: DPs: TRS: b(a(a(x1))) -> a(b(c(x1))) c(a(x1)) -> a(c(x1)) c(b(x1)) -> b(a(x1)) a(a(x1)) -> a(b(a(x1))) Qed