YES Problem: a(a(x)) -> b(c(x)) b(b(x)) -> a(c(x)) c(c(x)) -> a(b(x)) Proof: String Reversal Processor: a(a(x)) -> c(b(x)) b(b(x)) -> c(a(x)) c(c(x)) -> b(a(x)) DP Processor: DPs: a#(a(x)) -> b#(x) a#(a(x)) -> c#(b(x)) b#(b(x)) -> a#(x) b#(b(x)) -> c#(a(x)) c#(c(x)) -> a#(x) c#(c(x)) -> b#(a(x)) TRS: a(a(x)) -> c(b(x)) b(b(x)) -> c(a(x)) c(c(x)) -> b(a(x)) TDG Processor: DPs: a#(a(x)) -> b#(x) a#(a(x)) -> c#(b(x)) b#(b(x)) -> a#(x) b#(b(x)) -> c#(a(x)) c#(c(x)) -> a#(x) c#(c(x)) -> b#(a(x)) TRS: a(a(x)) -> c(b(x)) b(b(x)) -> c(a(x)) c(c(x)) -> b(a(x)) graph: c#(c(x)) -> b#(a(x)) -> b#(b(x)) -> c#(a(x)) c#(c(x)) -> b#(a(x)) -> b#(b(x)) -> a#(x) c#(c(x)) -> a#(x) -> a#(a(x)) -> c#(b(x)) c#(c(x)) -> a#(x) -> a#(a(x)) -> b#(x) b#(b(x)) -> c#(a(x)) -> c#(c(x)) -> b#(a(x)) b#(b(x)) -> c#(a(x)) -> c#(c(x)) -> a#(x) b#(b(x)) -> a#(x) -> a#(a(x)) -> c#(b(x)) b#(b(x)) -> a#(x) -> a#(a(x)) -> b#(x) a#(a(x)) -> c#(b(x)) -> c#(c(x)) -> b#(a(x)) a#(a(x)) -> c#(b(x)) -> c#(c(x)) -> a#(x) a#(a(x)) -> b#(x) -> b#(b(x)) -> c#(a(x)) a#(a(x)) -> b#(x) -> b#(b(x)) -> a#(x) Arctic Interpretation Processor: dimension: 1 interpretation: [c#](x0) = x0, [b#](x0) = x0, [a#](x0) = 4x0, [b](x0) = 4x0, [c](x0) = 4x0, [a](x0) = 4x0 orientation: a#(a(x)) = 8x >= x = b#(x) a#(a(x)) = 8x >= 4x = c#(b(x)) b#(b(x)) = 4x >= 4x = a#(x) b#(b(x)) = 4x >= 4x = c#(a(x)) c#(c(x)) = 4x >= 4x = a#(x) c#(c(x)) = 4x >= 4x = b#(a(x)) a(a(x)) = 8x >= 8x = c(b(x)) b(b(x)) = 8x >= 8x = c(a(x)) c(c(x)) = 8x >= 8x = b(a(x)) problem: DPs: b#(b(x)) -> a#(x) b#(b(x)) -> c#(a(x)) c#(c(x)) -> a#(x) c#(c(x)) -> b#(a(x)) TRS: a(a(x)) -> c(b(x)) b(b(x)) -> c(a(x)) c(c(x)) -> b(a(x)) EDG Processor: DPs: b#(b(x)) -> a#(x) b#(b(x)) -> c#(a(x)) c#(c(x)) -> a#(x) c#(c(x)) -> b#(a(x)) TRS: a(a(x)) -> c(b(x)) b(b(x)) -> c(a(x)) c(c(x)) -> b(a(x)) graph: c#(c(x)) -> b#(a(x)) -> b#(b(x)) -> a#(x) c#(c(x)) -> b#(a(x)) -> b#(b(x)) -> c#(a(x)) b#(b(x)) -> c#(a(x)) -> c#(c(x)) -> a#(x) b#(b(x)) -> c#(a(x)) -> c#(c(x)) -> b#(a(x)) SCC Processor: #sccs: 1 #rules: 2 #arcs: 4/16 DPs: c#(c(x)) -> b#(a(x)) b#(b(x)) -> c#(a(x)) TRS: a(a(x)) -> c(b(x)) b(b(x)) -> c(a(x)) c(c(x)) -> b(a(x)) Arctic Interpretation Processor: dimension: 2 interpretation: [c#](x0) = [2 0]x0 + [3], [b#](x0) = [2 0]x0 + [0], [1 0 ] [2] [b](x0) = [0 -&]x0 + [1], [0 1] [0] [c](x0) = [0 0]x0 + [2], [-& 0 ] [0] [a](x0) = [1 0 ]x0 + [2] orientation: c#(c(x)) = [2 3]x + [3] >= [1 2]x + [2] = b#(a(x)) b#(b(x)) = [3 2]x + [4] >= [1 2]x + [3] = c#(a(x)) [1 0] [2] [1 0] [2] a(a(x)) = [1 1]x + [2] >= [1 0]x + [2] = c(b(x)) [2 1] [3] [2 1] [3] b(b(x)) = [1 0]x + [2] >= [1 0]x + [2] = c(a(x)) [1 1] [3] [1 1 ] [2] c(c(x)) = [0 1]x + [2] >= [-& 0 ]x + [1] = b(a(x)) problem: DPs: b#(b(x)) -> c#(a(x)) TRS: a(a(x)) -> c(b(x)) b(b(x)) -> c(a(x)) c(c(x)) -> b(a(x)) EDG Processor: DPs: b#(b(x)) -> c#(a(x)) TRS: a(a(x)) -> c(b(x)) b(b(x)) -> c(a(x)) c(c(x)) -> b(a(x)) graph: Qed