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