YES Problem: a(a(x1)) -> b(c(x1)) b(b(x1)) -> a(c(c(c(x1)))) c(c(x1)) -> a(b(x1)) Proof: DP Processor: DPs: a#(a(x1)) -> c#(x1) a#(a(x1)) -> b#(c(x1)) b#(b(x1)) -> c#(x1) b#(b(x1)) -> c#(c(x1)) b#(b(x1)) -> c#(c(c(x1))) b#(b(x1)) -> a#(c(c(c(x1)))) c#(c(x1)) -> b#(x1) c#(c(x1)) -> a#(b(x1)) TRS: a(a(x1)) -> b(c(x1)) b(b(x1)) -> a(c(c(c(x1)))) c(c(x1)) -> a(b(x1)) TDG Processor: DPs: a#(a(x1)) -> c#(x1) a#(a(x1)) -> b#(c(x1)) b#(b(x1)) -> c#(x1) b#(b(x1)) -> c#(c(x1)) b#(b(x1)) -> c#(c(c(x1))) b#(b(x1)) -> a#(c(c(c(x1)))) c#(c(x1)) -> b#(x1) c#(c(x1)) -> a#(b(x1)) TRS: a(a(x1)) -> b(c(x1)) b(b(x1)) -> a(c(c(c(x1)))) c(c(x1)) -> a(b(x1)) graph: b#(b(x1)) -> c#(c(c(x1))) -> c#(c(x1)) -> a#(b(x1)) b#(b(x1)) -> c#(c(c(x1))) -> c#(c(x1)) -> b#(x1) b#(b(x1)) -> c#(c(x1)) -> c#(c(x1)) -> a#(b(x1)) b#(b(x1)) -> c#(c(x1)) -> c#(c(x1)) -> b#(x1) b#(b(x1)) -> c#(x1) -> c#(c(x1)) -> a#(b(x1)) b#(b(x1)) -> c#(x1) -> c#(c(x1)) -> b#(x1) b#(b(x1)) -> a#(c(c(c(x1)))) -> a#(a(x1)) -> b#(c(x1)) b#(b(x1)) -> a#(c(c(c(x1)))) -> a#(a(x1)) -> c#(x1) c#(c(x1)) -> b#(x1) -> b#(b(x1)) -> a#(c(c(c(x1)))) c#(c(x1)) -> b#(x1) -> b#(b(x1)) -> c#(c(c(x1))) c#(c(x1)) -> b#(x1) -> b#(b(x1)) -> c#(c(x1)) c#(c(x1)) -> b#(x1) -> b#(b(x1)) -> c#(x1) c#(c(x1)) -> a#(b(x1)) -> a#(a(x1)) -> b#(c(x1)) c#(c(x1)) -> a#(b(x1)) -> a#(a(x1)) -> c#(x1) a#(a(x1)) -> b#(c(x1)) -> b#(b(x1)) -> a#(c(c(c(x1)))) a#(a(x1)) -> b#(c(x1)) -> b#(b(x1)) -> c#(c(c(x1))) a#(a(x1)) -> b#(c(x1)) -> b#(b(x1)) -> c#(c(x1)) a#(a(x1)) -> b#(c(x1)) -> b#(b(x1)) -> c#(x1) a#(a(x1)) -> c#(x1) -> c#(c(x1)) -> a#(b(x1)) a#(a(x1)) -> c#(x1) -> c#(c(x1)) -> b#(x1) Arctic Interpretation Processor: dimension: 2 interpretation: [b#](x0) = [1 -&]x0 + [0], [c#](x0) = [1 -&]x0 + [0], [a#](x0) = [-& 0 ]x0 + [0], [1 -&] [3] [b](x0) = [0 -&]x0 + [0], [0 -&] [2] [c](x0) = [2 -&]x0 + [0], [-1 0 ] [2] [a](x0) = [1 -&]x0 + [3] orientation: a#(a(x1)) = [1 -&]x1 + [3] >= [1 -&]x1 + [0] = c#(x1) a#(a(x1)) = [1 -&]x1 + [3] >= [1 -&]x1 + [3] = b#(c(x1)) b#(b(x1)) = [2 -&]x1 + [4] >= [1 -&]x1 + [0] = c#(x1) b#(b(x1)) = [2 -&]x1 + [4] >= [1 -&]x1 + [3] = c#(c(x1)) b#(b(x1)) = [2 -&]x1 + [4] >= [1 -&]x1 + [3] = c#(c(c(x1))) b#(b(x1)) = [2 -&]x1 + [4] >= [2 -&]x1 + [4] = a#(c(c(c(x1)))) c#(c(x1)) = [1 -&]x1 + [3] >= [1 -&]x1 + [0] = b#(x1) c#(c(x1)) = [1 -&]x1 + [3] >= [0 -&]x1 + [0] = a#(b(x1)) [1 -1] [3] [1 -&] [3] a(a(x1)) = [0 1 ]x1 + [3] >= [0 -&]x1 + [2] = b(c(x1)) [2 -&] [4] [2 -&] [4] b(b(x1)) = [1 -&]x1 + [3] >= [1 -&]x1 + [3] = a(c(c(c(x1)))) [0 -&] [2] [0 -&] [2] c(c(x1)) = [2 -&]x1 + [4] >= [2 -&]x1 + [4] = a(b(x1)) problem: DPs: a#(a(x1)) -> c#(x1) a#(a(x1)) -> b#(c(x1)) b#(b(x1)) -> a#(c(c(c(x1)))) c#(c(x1)) -> b#(x1) TRS: a(a(x1)) -> b(c(x1)) b(b(x1)) -> a(c(c(c(x1)))) c(c(x1)) -> a(b(x1)) EDG Processor: DPs: a#(a(x1)) -> c#(x1) a#(a(x1)) -> b#(c(x1)) b#(b(x1)) -> a#(c(c(c(x1)))) c#(c(x1)) -> b#(x1) TRS: a(a(x1)) -> b(c(x1)) b(b(x1)) -> a(c(c(c(x1)))) c(c(x1)) -> a(b(x1)) graph: b#(b(x1)) -> a#(c(c(c(x1)))) -> a#(a(x1)) -> c#(x1) b#(b(x1)) -> a#(c(c(c(x1)))) -> a#(a(x1)) -> b#(c(x1)) c#(c(x1)) -> b#(x1) -> b#(b(x1)) -> a#(c(c(c(x1)))) a#(a(x1)) -> b#(c(x1)) -> b#(b(x1)) -> a#(c(c(c(x1)))) a#(a(x1)) -> c#(x1) -> c#(c(x1)) -> b#(x1) Arctic Interpretation Processor: dimension: 2 interpretation: [b#](x0) = [-& 1 ]x0 + [0], [c#](x0) = [0 0]x0 + [3], [a#](x0) = [0 0]x0 + [3], [-& 0 ] [0] [b](x0) = [-2 1 ]x0 + [2], [-4 2 ] [2] [c](x0) = [-2 -1]x0 + [1], [-4 0 ] [2 ] [a](x0) = [0 -1]x0 + [-2] orientation: a#(a(x1)) = [0 0]x1 + [3] >= [0 0]x1 + [3] = c#(x1) a#(a(x1)) = [0 0]x1 + [3] >= [-1 0 ]x1 + [2] = b#(c(x1)) b#(b(x1)) = [-1 2 ]x1 + [3] >= [-1 2 ]x1 + [3] = a#(c(c(c(x1)))) c#(c(x1)) = [-2 2 ]x1 + [3] >= [-& 1 ]x1 + [0] = b#(x1) [0 -1] [2] [-2 -1] [1] a(a(x1)) = [-1 0 ]x1 + [2] >= [-1 0 ]x1 + [2] = b(c(x1)) [-2 1 ] [2] [-2 -1] [2] b(b(x1)) = [-1 2 ]x1 + [3] >= [-1 2 ]x1 + [3] = a(c(c(c(x1)))) [0 1 ] [3] [-2 1 ] [2] c(c(x1)) = [-3 0 ]x1 + [1] >= [-3 0 ]x1 + [1] = a(b(x1)) problem: DPs: a#(a(x1)) -> c#(x1) a#(a(x1)) -> b#(c(x1)) b#(b(x1)) -> a#(c(c(c(x1)))) TRS: a(a(x1)) -> b(c(x1)) b(b(x1)) -> a(c(c(c(x1)))) c(c(x1)) -> a(b(x1)) EDG Processor: DPs: a#(a(x1)) -> c#(x1) a#(a(x1)) -> b#(c(x1)) b#(b(x1)) -> a#(c(c(c(x1)))) TRS: a(a(x1)) -> b(c(x1)) b(b(x1)) -> a(c(c(c(x1)))) c(c(x1)) -> a(b(x1)) graph: b#(b(x1)) -> a#(c(c(c(x1)))) -> a#(a(x1)) -> b#(c(x1)) b#(b(x1)) -> a#(c(c(c(x1)))) -> a#(a(x1)) -> c#(x1) a#(a(x1)) -> b#(c(x1)) -> b#(b(x1)) -> a#(c(c(c(x1)))) SCC Processor: #sccs: 1 #rules: 2 #arcs: 3/9 DPs: b#(b(x1)) -> a#(c(c(c(x1)))) a#(a(x1)) -> b#(c(x1)) TRS: a(a(x1)) -> b(c(x1)) b(b(x1)) -> a(c(c(c(x1)))) c(c(x1)) -> a(b(x1)) Matrix Interpretation Processor: dim=3 interpretation: [b#](x0) = [0 0 1]x0 + [1], [a#](x0) = [0 0 1]x0 + [1], [0 0 0] [0] [b](x0) = [0 0 1]x0 + [0] [1 0 2] [1], [0 0 1] [0] [c](x0) = [2 0 2]x0 + [2] [1 0 0] [0], [0 0 0] [0] [a](x0) = [2 0 1]x0 + [1] [1 1 0] [0] orientation: b#(b(x1)) = [1 0 2]x1 + [2] >= [1 0 0]x1 + [1] = a#(c(c(c(x1)))) a#(a(x1)) = [1 1 0]x1 + [1] >= [1 0 0]x1 + [1] = b#(c(x1)) [0 0 0] [0] [0 0 0] [0] a(a(x1)) = [1 1 0]x1 + [1] >= [1 0 0]x1 + [0] = b(c(x1)) [2 0 1] [1] [2 0 1] [1] [0 0 0] [0] [0 0 0] [0] b(b(x1)) = [1 0 2]x1 + [1] >= [1 0 2]x1 + [1] = a(c(c(c(x1)))) [2 0 4] [3] [2 0 3] [2] [1 0 0] [0] [0 0 0] [0] c(c(x1)) = [2 0 2]x1 + [2] >= [1 0 2]x1 + [2] = a(b(x1)) [0 0 1] [0] [0 0 1] [0] problem: DPs: a#(a(x1)) -> b#(c(x1)) TRS: a(a(x1)) -> b(c(x1)) b(b(x1)) -> a(c(c(c(x1)))) c(c(x1)) -> a(b(x1)) EDG Processor: DPs: a#(a(x1)) -> b#(c(x1)) TRS: a(a(x1)) -> b(c(x1)) b(b(x1)) -> a(c(c(c(x1)))) c(c(x1)) -> a(b(x1)) graph: Qed