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