YES Problem: a(a(x1)) -> b(b(c(x1))) a(c(x1)) -> x1 c(b(x1)) -> a(c(a(x1))) Proof: String Reversal Processor: a(a(x1)) -> c(b(b(x1))) c(a(x1)) -> x1 b(c(x1)) -> a(c(a(x1))) DP Processor: DPs: a#(a(x1)) -> b#(x1) a#(a(x1)) -> b#(b(x1)) a#(a(x1)) -> c#(b(b(x1))) b#(c(x1)) -> a#(x1) b#(c(x1)) -> c#(a(x1)) b#(c(x1)) -> a#(c(a(x1))) TRS: a(a(x1)) -> c(b(b(x1))) c(a(x1)) -> x1 b(c(x1)) -> a(c(a(x1))) TDG Processor: DPs: a#(a(x1)) -> b#(x1) a#(a(x1)) -> b#(b(x1)) a#(a(x1)) -> c#(b(b(x1))) b#(c(x1)) -> a#(x1) b#(c(x1)) -> c#(a(x1)) b#(c(x1)) -> a#(c(a(x1))) TRS: a(a(x1)) -> c(b(b(x1))) c(a(x1)) -> x1 b(c(x1)) -> a(c(a(x1))) graph: b#(c(x1)) -> a#(c(a(x1))) -> a#(a(x1)) -> c#(b(b(x1))) b#(c(x1)) -> a#(c(a(x1))) -> a#(a(x1)) -> b#(b(x1)) b#(c(x1)) -> a#(c(a(x1))) -> a#(a(x1)) -> b#(x1) b#(c(x1)) -> a#(x1) -> a#(a(x1)) -> c#(b(b(x1))) b#(c(x1)) -> a#(x1) -> a#(a(x1)) -> b#(b(x1)) b#(c(x1)) -> a#(x1) -> a#(a(x1)) -> b#(x1) a#(a(x1)) -> b#(b(x1)) -> b#(c(x1)) -> a#(c(a(x1))) a#(a(x1)) -> b#(b(x1)) -> b#(c(x1)) -> c#(a(x1)) a#(a(x1)) -> b#(b(x1)) -> b#(c(x1)) -> a#(x1) a#(a(x1)) -> b#(x1) -> b#(c(x1)) -> a#(c(a(x1))) a#(a(x1)) -> b#(x1) -> b#(c(x1)) -> c#(a(x1)) a#(a(x1)) -> b#(x1) -> b#(c(x1)) -> a#(x1) SCC Processor: #sccs: 1 #rules: 4 #arcs: 12/36 DPs: b#(c(x1)) -> a#(c(a(x1))) a#(a(x1)) -> b#(x1) b#(c(x1)) -> a#(x1) a#(a(x1)) -> b#(b(x1)) TRS: a(a(x1)) -> c(b(b(x1))) c(a(x1)) -> x1 b(c(x1)) -> a(c(a(x1))) Arctic Interpretation Processor: dimension: 3 interpretation: [b#](x0) = [1 0 -&]x0 + [0], [a#](x0) = [0 0 1]x0 + [0], [-& 0 -&] [0 ] [b](x0) = [0 -& -&]x0 + [-&] [1 0 -&] [0 ], [0 1 0 ] [1] [c](x0) = [0 0 0 ]x0 + [1] [0 0 -&] [0], [-& -& 0 ] [1 ] [a](x0) = [-& 0 0 ]x0 + [-&] [0 1 0 ] [1 ] orientation: b#(c(x1)) = [1 2 1]x1 + [2] >= [0 1 1]x1 + [2] = a#(c(a(x1))) a#(a(x1)) = [1 2 1]x1 + [2] >= [1 0 -&]x1 + [0] = b#(x1) b#(c(x1)) = [1 2 1]x1 + [2] >= [0 0 1]x1 + [0] = a#(x1) a#(a(x1)) = [1 2 1]x1 + [2] >= [0 1 -&]x1 + [1] = b#(b(x1)) [0 1 0] [1] [0 1 -&] [1] a(a(x1)) = [0 1 0]x1 + [1] >= [0 1 -&]x1 + [1] = c(b(b(x1))) [0 1 1] [1] [0 0 -&] [0] [0 1 1 ] [1] c(a(x1)) = [0 1 0 ]x1 + [1] >= x1 = x1 [-& 0 0 ] [1] [0 0 0] [1] [-& 0 0 ] [1] b(c(x1)) = [0 1 0]x1 + [1] >= [0 1 0 ]x1 + [1] = a(c(a(x1))) [1 2 1] [2] [1 2 1 ] [2] problem: DPs: b#(c(x1)) -> a#(c(a(x1))) a#(a(x1)) -> b#(x1) b#(c(x1)) -> a#(x1) TRS: a(a(x1)) -> c(b(b(x1))) c(a(x1)) -> x1 b(c(x1)) -> a(c(a(x1))) EDG Processor: DPs: b#(c(x1)) -> a#(c(a(x1))) a#(a(x1)) -> b#(x1) b#(c(x1)) -> a#(x1) TRS: a(a(x1)) -> c(b(b(x1))) c(a(x1)) -> x1 b(c(x1)) -> a(c(a(x1))) graph: b#(c(x1)) -> a#(c(a(x1))) -> a#(a(x1)) -> b#(x1) b#(c(x1)) -> a#(x1) -> a#(a(x1)) -> b#(x1) a#(a(x1)) -> b#(x1) -> b#(c(x1)) -> a#(x1) a#(a(x1)) -> b#(x1) -> b#(c(x1)) -> a#(c(a(x1))) Arctic Interpretation Processor: dimension: 3 interpretation: [b#](x0) = [1 0 -&]x0 + [1], [a#](x0) = [0 0 0]x0 + [0], [-& -& 0 ] [0 ] [b](x0) = [0 -& 1 ]x0 + [0 ] [0 -& -&] [-&], [0 0 0 ] [1] [c](x0) = [0 -& 0 ]x0 + [0] [1 0 0 ] [1], [0 0 -&] [1] [a](x0) = [1 0 0 ]x0 + [1] [-& 0 -&] [1] orientation: b#(c(x1)) = [1 1 1]x1 + [2] >= [1 1 0]x1 + [2] = a#(c(a(x1))) a#(a(x1)) = [1 0 0]x1 + [1] >= [1 0 -&]x1 + [1] = b#(x1) b#(c(x1)) = [1 1 1]x1 + [2] >= [0 0 0]x1 + [0] = a#(x1) [1 0 0] [1] [1 -& 0 ] [1] a(a(x1)) = [1 1 0]x1 + [2] >= [0 -& 0 ]x1 + [0] = c(b(b(x1))) [1 0 0] [1] [1 -& 0 ] [1] [1 0 0 ] [1] c(a(x1)) = [0 0 -&]x1 + [1] >= x1 = x1 [1 1 0 ] [2] [1 0 0] [1] [1 0 0 ] [1] b(c(x1)) = [2 1 1]x1 + [2] >= [2 1 1 ]x1 + [2] = a(c(a(x1))) [0 0 0] [1] [0 0 -&] [1] problem: DPs: b#(c(x1)) -> a#(c(a(x1))) a#(a(x1)) -> b#(x1) TRS: a(a(x1)) -> c(b(b(x1))) c(a(x1)) -> x1 b(c(x1)) -> a(c(a(x1))) EDG Processor: DPs: b#(c(x1)) -> a#(c(a(x1))) a#(a(x1)) -> b#(x1) TRS: a(a(x1)) -> c(b(b(x1))) c(a(x1)) -> x1 b(c(x1)) -> a(c(a(x1))) graph: b#(c(x1)) -> a#(c(a(x1))) -> a#(a(x1)) -> b#(x1) a#(a(x1)) -> b#(x1) -> b#(c(x1)) -> a#(c(a(x1))) Arctic Interpretation Processor: dimension: 3 interpretation: [b#](x0) = [0 0 1]x0 + [1], [a#](x0) = [0 -& -&]x0 + [1], [-& 1 0 ] [0 ] [b](x0) = [-& -& 0 ]x0 + [-&] [-& 0 -&] [0 ], [-& 0 -&] [0] [c](x0) = [0 0 1 ]x0 + [1] [0 0 0 ] [1], [0 0 1 ] [0] [a](x0) = [0 -& -&]x0 + [1] [0 -& 0 ] [1] orientation: b#(c(x1)) = [1 1 1]x1 + [2] >= [0 -& -&]x1 + [1] = a#(c(a(x1))) a#(a(x1)) = [0 0 1]x1 + [1] >= [0 0 1]x1 + [1] = b#(x1) [1 0 1] [2] [-& 0 -&] [0] a(a(x1)) = [0 0 1]x1 + [1] >= [-& 0 1 ]x1 + [1] = c(b(b(x1))) [0 0 1] [1] [-& 0 1 ] [1] [0 -& -&] [1] c(a(x1)) = [1 0 1 ]x1 + [2] >= x1 = x1 [0 0 1 ] [1] [1 1 2] [2] [1 1 2 ] [2] b(c(x1)) = [0 0 0]x1 + [1] >= [0 -& -&]x1 + [1] = a(c(a(x1))) [0 0 1] [1] [0 0 1 ] [1] problem: DPs: a#(a(x1)) -> b#(x1) TRS: a(a(x1)) -> c(b(b(x1))) c(a(x1)) -> x1 b(c(x1)) -> a(c(a(x1))) EDG Processor: DPs: a#(a(x1)) -> b#(x1) TRS: a(a(x1)) -> c(b(b(x1))) c(a(x1)) -> x1 b(c(x1)) -> a(c(a(x1))) graph: Qed