YES Problem: c(a(a(b(c(a(x1)))))) -> a(a(b(c(c(a(a(b(c(x1))))))))) Proof: DP Processor: DPs: c#(a(a(b(c(a(x1)))))) -> c#(x1) c#(a(a(b(c(a(x1)))))) -> c#(a(a(b(c(x1))))) c#(a(a(b(c(a(x1)))))) -> c#(c(a(a(b(c(x1)))))) TRS: c(a(a(b(c(a(x1)))))) -> a(a(b(c(c(a(a(b(c(x1))))))))) Matrix Interpretation Processor: dim=5 interpretation: [c#](x0) = [1 0 0 0 0]x0, [0 0 0 0 0] [0] [0 0 0 0 0] [0] [b](x0) = [0 0 1 0 0]x0 + [0] [0 1 0 0 0] [0] [0 0 0 0 0] [1], [0 0 1 0 1] [0 0 0 1 0] [c](x0) = [1 0 0 0 0]x0 [0 0 0 0 1] [0 1 1 0 1] , [1 0 0 1 0] [0] [0 0 1 0 0] [0] [a](x0) = [0 1 0 0 0]x0 + [0] [1 0 1 0 0] [1] [1 1 0 0 0] [0] orientation: c#(a(a(b(c(a(x1)))))) = [2 0 1 1 0]x1 + [2] >= [1 0 0 0 0]x1 = c#(x1) c#(a(a(b(c(a(x1)))))) = [2 0 1 1 0]x1 + [2] >= [1 0 0 1 0]x1 + [1] = c#(a(a(b(c(x1))))) c#(a(a(b(c(a(x1)))))) = [2 0 1 1 0]x1 + [2] >= [2 0 0 1 0]x1 = c#(c(a(a(b(c(x1)))))) [3 0 1 2 0] [1] [3 0 0 2 0] [1] [1 0 1 0 0] [2] [0 0 0 0 0] [0] c(a(a(b(c(a(x1)))))) = [2 0 1 1 0]x1 + [2] >= [2 0 0 1 0]x1 + [0] = a(a(b(c(c(a(a(b(c(x1))))))))) [2 0 1 1 0] [1] [1 0 0 1 0] [1] [3 0 1 2 0] [1] [3 0 0 2 0] [0] problem: DPs: TRS: c(a(a(b(c(a(x1)))))) -> a(a(b(c(c(a(a(b(c(x1))))))))) Qed