YES Problem: a(x1) -> x1 a(a(b(x1))) -> b(b(a(a(x1)))) b(x1) -> c(c(a(x1))) Proof: String Reversal Processor: a(x1) -> x1 b(a(a(x1))) -> a(a(b(b(x1)))) b(x1) -> a(c(c(x1))) DP Processor: DPs: b#(a(a(x1))) -> b#(x1) b#(a(a(x1))) -> b#(b(x1)) b#(a(a(x1))) -> a#(b(b(x1))) b#(a(a(x1))) -> a#(a(b(b(x1)))) b#(x1) -> a#(c(c(x1))) TRS: a(x1) -> x1 b(a(a(x1))) -> a(a(b(b(x1)))) b(x1) -> a(c(c(x1))) TDG Processor: DPs: b#(a(a(x1))) -> b#(x1) b#(a(a(x1))) -> b#(b(x1)) b#(a(a(x1))) -> a#(b(b(x1))) b#(a(a(x1))) -> a#(a(b(b(x1)))) b#(x1) -> a#(c(c(x1))) TRS: a(x1) -> x1 b(a(a(x1))) -> a(a(b(b(x1)))) b(x1) -> a(c(c(x1))) graph: b#(a(a(x1))) -> b#(b(x1)) -> b#(x1) -> a#(c(c(x1))) b#(a(a(x1))) -> b#(b(x1)) -> b#(a(a(x1))) -> a#(a(b(b(x1)))) b#(a(a(x1))) -> b#(b(x1)) -> b#(a(a(x1))) -> a#(b(b(x1))) b#(a(a(x1))) -> b#(b(x1)) -> b#(a(a(x1))) -> b#(b(x1)) b#(a(a(x1))) -> b#(b(x1)) -> b#(a(a(x1))) -> b#(x1) b#(a(a(x1))) -> b#(x1) -> b#(x1) -> a#(c(c(x1))) b#(a(a(x1))) -> b#(x1) -> b#(a(a(x1))) -> a#(a(b(b(x1)))) b#(a(a(x1))) -> b#(x1) -> b#(a(a(x1))) -> a#(b(b(x1))) b#(a(a(x1))) -> b#(x1) -> b#(a(a(x1))) -> b#(b(x1)) b#(a(a(x1))) -> b#(x1) -> b#(a(a(x1))) -> b#(x1) SCC Processor: #sccs: 1 #rules: 2 #arcs: 10/25 DPs: b#(a(a(x1))) -> b#(b(x1)) b#(a(a(x1))) -> b#(x1) TRS: a(x1) -> x1 b(a(a(x1))) -> a(a(b(b(x1)))) b(x1) -> a(c(c(x1))) Arctic Interpretation Processor: dimension: 2 usable rules: a(x1) -> x1 b(a(a(x1))) -> a(a(b(b(x1)))) b(x1) -> a(c(c(x1))) interpretation: [b#](x0) = [0 0]x0, [0 -&] [-&] [b](x0) = [1 0 ]x0 + [0 ], [0 0] [-&] [a](x0) = [1 0]x0 + [0 ], [0 -&] [c](x0) = [0 -&]x0 orientation: b#(a(a(x1))) = [1 1]x1 + [0] >= [1 0]x1 + [0] = b#(b(x1)) b#(a(a(x1))) = [1 1]x1 + [0] >= [0 0]x1 = b#(x1) [0 0] [-&] a(x1) = [1 0]x1 + [0 ] >= x1 = x1 [1 0] [0] [1 0] [0] b(a(a(x1))) = [2 1]x1 + [1] >= [2 1]x1 + [1] = a(a(b(b(x1)))) [0 -&] [-&] [0 -&] [-&] b(x1) = [1 0 ]x1 + [0 ] >= [1 -&]x1 + [0 ] = a(c(c(x1))) problem: DPs: b#(a(a(x1))) -> b#(b(x1)) TRS: a(x1) -> x1 b(a(a(x1))) -> a(a(b(b(x1)))) b(x1) -> a(c(c(x1))) Restore Modifier: DPs: b#(a(a(x1))) -> b#(b(x1)) TRS: a(x1) -> x1 b(a(a(x1))) -> a(a(b(b(x1)))) b(x1) -> a(c(c(x1))) EDG Processor: DPs: b#(a(a(x1))) -> b#(b(x1)) TRS: a(x1) -> x1 b(a(a(x1))) -> a(a(b(b(x1)))) b(x1) -> a(c(c(x1))) graph: b#(a(a(x1))) -> b#(b(x1)) -> b#(a(a(x1))) -> b#(b(x1)) Arctic Interpretation Processor: dimension: 2 usable rules: a(x1) -> x1 b(a(a(x1))) -> a(a(b(b(x1)))) b(x1) -> a(c(c(x1))) interpretation: [b#](x0) = [0 0]x0 + [0], [0 -&] [0] [b](x0) = [0 0 ]x0 + [0], [0 1] [0] [a](x0) = [0 0]x0 + [0], [-& 1 ] [0 ] [c](x0) = [-& -&]x0 + [-&] orientation: b#(a(a(x1))) = [1 1]x1 + [1] >= [0 0]x1 + [0] = b#(b(x1)) [0 1] [0] a(x1) = [0 0]x1 + [0] >= x1 = x1 [1 1] [1] [1 1] [1] b(a(a(x1))) = [1 1]x1 + [1] >= [1 1]x1 + [1] = a(a(b(b(x1)))) [0 -&] [0] [0] b(x1) = [0 0 ]x1 + [0] >= [0] = a(c(c(x1))) problem: DPs: TRS: a(x1) -> x1 b(a(a(x1))) -> a(a(b(b(x1)))) b(x1) -> a(c(c(x1))) Qed