YES Problem: a(a(x1)) -> c(b(x1)) b(b(x1)) -> c(a(x1)) c(c(x1)) -> b(a(x1)) Proof: String Reversal Processor: a(a(x1)) -> b(c(x1)) b(b(x1)) -> a(c(x1)) c(c(x1)) -> a(b(x1)) DP Processor: DPs: a#(a(x1)) -> c#(x1) a#(a(x1)) -> b#(c(x1)) b#(b(x1)) -> c#(x1) b#(b(x1)) -> a#(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(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)) -> a#(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(x1)) c(c(x1)) -> a(b(x1)) graph: 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(x1)) -> a#(a(x1)) -> b#(c(x1)) b#(b(x1)) -> a#(c(x1)) -> a#(a(x1)) -> c#(x1) c#(c(x1)) -> b#(x1) -> b#(b(x1)) -> a#(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(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: 1 usable rules: a(a(x1)) -> b(c(x1)) b(b(x1)) -> a(c(x1)) c(c(x1)) -> a(b(x1)) interpretation: [c#](x0) = x0 + 0, [b](x0) = 2x0 + 0, [a#](x0) = x0 + 0, [b#](x0) = x0, [a](x0) = 2x0 + 0, [c](x0) = 2x0 + 0 orientation: a#(a(x1)) = 2x1 + 0 >= x1 + 0 = c#(x1) a#(a(x1)) = 2x1 + 0 >= 2x1 + 0 = b#(c(x1)) b#(b(x1)) = 2x1 + 0 >= x1 + 0 = c#(x1) b#(b(x1)) = 2x1 + 0 >= 2x1 + 0 = a#(c(x1)) c#(c(x1)) = 2x1 + 0 >= x1 = b#(x1) c#(c(x1)) = 2x1 + 0 >= 2x1 + 0 = a#(b(x1)) a(a(x1)) = 4x1 + 2 >= 4x1 + 2 = b(c(x1)) b(b(x1)) = 4x1 + 2 >= 4x1 + 2 = a(c(x1)) c(c(x1)) = 4x1 + 2 >= 4x1 + 2 = a(b(x1)) problem: DPs: a#(a(x1)) -> c#(x1) a#(a(x1)) -> b#(c(x1)) b#(b(x1)) -> c#(x1) b#(b(x1)) -> a#(c(x1)) c#(c(x1)) -> a#(b(x1)) TRS: a(a(x1)) -> b(c(x1)) b(b(x1)) -> a(c(x1)) c(c(x1)) -> a(b(x1)) Restore Modifier: DPs: a#(a(x1)) -> c#(x1) a#(a(x1)) -> b#(c(x1)) b#(b(x1)) -> c#(x1) b#(b(x1)) -> a#(c(x1)) c#(c(x1)) -> a#(b(x1)) TRS: a(a(x1)) -> b(c(x1)) b(b(x1)) -> a(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)) -> c#(x1) b#(b(x1)) -> a#(c(x1)) c#(c(x1)) -> a#(b(x1)) TRS: a(a(x1)) -> b(c(x1)) b(b(x1)) -> a(c(x1)) c(c(x1)) -> a(b(x1)) graph: b#(b(x1)) -> c#(x1) -> c#(c(x1)) -> a#(b(x1)) b#(b(x1)) -> a#(c(x1)) -> a#(a(x1)) -> c#(x1) b#(b(x1)) -> a#(c(x1)) -> a#(a(x1)) -> b#(c(x1)) c#(c(x1)) -> a#(b(x1)) -> a#(a(x1)) -> c#(x1) c#(c(x1)) -> a#(b(x1)) -> a#(a(x1)) -> b#(c(x1)) a#(a(x1)) -> b#(c(x1)) -> b#(b(x1)) -> c#(x1) a#(a(x1)) -> b#(c(x1)) -> b#(b(x1)) -> a#(c(x1)) a#(a(x1)) -> c#(x1) -> c#(c(x1)) -> a#(b(x1)) Arctic Interpretation Processor: dimension: 1 usable rules: a(a(x1)) -> b(c(x1)) b(b(x1)) -> a(c(x1)) c(c(x1)) -> a(b(x1)) interpretation: [c#](x0) = 1x0, [b](x0) = 1x0, [a#](x0) = x0, [b#](x0) = x0, [a](x0) = 1x0, [c](x0) = 1x0 orientation: a#(a(x1)) = 1x1 >= 1x1 = c#(x1) a#(a(x1)) = 1x1 >= 1x1 = b#(c(x1)) b#(b(x1)) = 1x1 >= 1x1 = c#(x1) b#(b(x1)) = 1x1 >= 1x1 = a#(c(x1)) c#(c(x1)) = 2x1 >= 1x1 = a#(b(x1)) a(a(x1)) = 2x1 >= 2x1 = b(c(x1)) b(b(x1)) = 2x1 >= 2x1 = a(c(x1)) c(c(x1)) = 2x1 >= 2x1 = a(b(x1)) problem: DPs: a#(a(x1)) -> c#(x1) a#(a(x1)) -> b#(c(x1)) b#(b(x1)) -> c#(x1) b#(b(x1)) -> a#(c(x1)) TRS: a(a(x1)) -> b(c(x1)) b(b(x1)) -> a(c(x1)) c(c(x1)) -> a(b(x1)) Restore Modifier: DPs: a#(a(x1)) -> c#(x1) a#(a(x1)) -> b#(c(x1)) b#(b(x1)) -> c#(x1) b#(b(x1)) -> a#(c(x1)) TRS: a(a(x1)) -> b(c(x1)) b(b(x1)) -> a(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)) -> c#(x1) b#(b(x1)) -> a#(c(x1)) TRS: a(a(x1)) -> b(c(x1)) b(b(x1)) -> a(c(x1)) c(c(x1)) -> a(b(x1)) graph: b#(b(x1)) -> a#(c(x1)) -> a#(a(x1)) -> b#(c(x1)) b#(b(x1)) -> a#(c(x1)) -> a#(a(x1)) -> c#(x1) a#(a(x1)) -> b#(c(x1)) -> b#(b(x1)) -> a#(c(x1)) a#(a(x1)) -> b#(c(x1)) -> b#(b(x1)) -> c#(x1) SCC Processor: #sccs: 1 #rules: 2 #arcs: 4/16 DPs: b#(b(x1)) -> a#(c(x1)) a#(a(x1)) -> b#(c(x1)) TRS: a(a(x1)) -> b(c(x1)) b(b(x1)) -> a(c(x1)) c(c(x1)) -> a(b(x1)) Arctic Interpretation Processor: dimension: 2 usable rules: a(a(x1)) -> b(c(x1)) b(b(x1)) -> a(c(x1)) c(c(x1)) -> a(b(x1)) interpretation: [-& 0 ] [0] [b](x0) = [0 2 ]x0 + [3], [a#](x0) = [-& -2]x0 + [2], [b#](x0) = [-& 0 ]x0 + [0], [0 0 ] [2 ] [a](x0) = [2 -4]x0 + [-4], [0 2 ] [0] [c](x0) = [0 -&]x0 + [2] orientation: b#(b(x1)) = [0 2]x1 + [3] >= [-2 -&]x1 + [2] = a#(c(x1)) a#(a(x1)) = [0 -6]x1 + [2] >= [0 -&]x1 + [2] = b#(c(x1)) [2 0] [2] [0 -&] [2] a(a(x1)) = [2 2]x1 + [4] >= [2 2 ]x1 + [4] = b(c(x1)) [0 2] [3] [0 2] [2] b(b(x1)) = [2 4]x1 + [5] >= [2 4]x1 + [2] = a(c(x1)) [2 2] [4] [0 2 ] [3] c(c(x1)) = [0 2]x1 + [2] >= [-4 2 ]x1 + [2] = a(b(x1)) problem: DPs: a#(a(x1)) -> b#(c(x1)) TRS: a(a(x1)) -> b(c(x1)) b(b(x1)) -> a(c(x1)) c(c(x1)) -> a(b(x1)) Restore Modifier: DPs: a#(a(x1)) -> b#(c(x1)) TRS: a(a(x1)) -> b(c(x1)) b(b(x1)) -> a(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(x1)) c(c(x1)) -> a(b(x1)) graph: SCC Processor: #sccs: 0 #rules: 0 #arcs: 0/1