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