YES Problem: a(b(x1)) -> x1 a(c(x1)) -> c(c(b(a(x1)))) b(c(x1)) -> a(b(x1)) Proof: DP Processor: DPs: a#(c(x1)) -> a#(x1) a#(c(x1)) -> b#(a(x1)) b#(c(x1)) -> b#(x1) b#(c(x1)) -> a#(b(x1)) TRS: a(b(x1)) -> x1 a(c(x1)) -> c(c(b(a(x1)))) b(c(x1)) -> a(b(x1)) TDG Processor: DPs: a#(c(x1)) -> a#(x1) a#(c(x1)) -> b#(a(x1)) b#(c(x1)) -> b#(x1) b#(c(x1)) -> a#(b(x1)) TRS: a(b(x1)) -> x1 a(c(x1)) -> c(c(b(a(x1)))) b(c(x1)) -> a(b(x1)) graph: b#(c(x1)) -> b#(x1) -> b#(c(x1)) -> a#(b(x1)) b#(c(x1)) -> b#(x1) -> b#(c(x1)) -> b#(x1) b#(c(x1)) -> a#(b(x1)) -> a#(c(x1)) -> b#(a(x1)) b#(c(x1)) -> a#(b(x1)) -> a#(c(x1)) -> a#(x1) a#(c(x1)) -> b#(a(x1)) -> b#(c(x1)) -> a#(b(x1)) a#(c(x1)) -> b#(a(x1)) -> b#(c(x1)) -> b#(x1) a#(c(x1)) -> a#(x1) -> a#(c(x1)) -> b#(a(x1)) a#(c(x1)) -> a#(x1) -> a#(c(x1)) -> a#(x1) Arctic Interpretation Processor: dimension: 1 interpretation: [b#](x0) = x0, [a#](x0) = 2x0 + 0, [c](x0) = 1x0 + 2, [a](x0) = 1x0, [b](x0) = -1x0 + 0 orientation: a#(c(x1)) = 3x1 + 4 >= 2x1 + 0 = a#(x1) a#(c(x1)) = 3x1 + 4 >= 1x1 = b#(a(x1)) b#(c(x1)) = 1x1 + 2 >= x1 = b#(x1) b#(c(x1)) = 1x1 + 2 >= 1x1 + 2 = a#(b(x1)) a(b(x1)) = x1 + 1 >= x1 = x1 a(c(x1)) = 2x1 + 3 >= 2x1 + 3 = c(c(b(a(x1)))) b(c(x1)) = x1 + 1 >= x1 + 1 = a(b(x1)) problem: DPs: b#(c(x1)) -> a#(b(x1)) TRS: a(b(x1)) -> x1 a(c(x1)) -> c(c(b(a(x1)))) b(c(x1)) -> a(b(x1)) EDG Processor: DPs: b#(c(x1)) -> a#(b(x1)) TRS: a(b(x1)) -> x1 a(c(x1)) -> c(c(b(a(x1)))) b(c(x1)) -> a(b(x1)) graph: Qed