YES Problem: a(x1) -> b(x1) a(b(x1)) -> b(a(c(x1))) b(b(x1)) -> x1 c(c(x1)) -> a(x1) Proof: String Reversal Processor: a(x1) -> b(x1) b(a(x1)) -> c(a(b(x1))) b(b(x1)) -> x1 c(c(x1)) -> a(x1) DP Processor: DPs: a#(x1) -> b#(x1) b#(a(x1)) -> b#(x1) b#(a(x1)) -> a#(b(x1)) b#(a(x1)) -> c#(a(b(x1))) c#(c(x1)) -> a#(x1) TRS: a(x1) -> b(x1) b(a(x1)) -> c(a(b(x1))) b(b(x1)) -> x1 c(c(x1)) -> a(x1) TDG Processor: DPs: a#(x1) -> b#(x1) b#(a(x1)) -> b#(x1) b#(a(x1)) -> a#(b(x1)) b#(a(x1)) -> c#(a(b(x1))) c#(c(x1)) -> a#(x1) TRS: a(x1) -> b(x1) b(a(x1)) -> c(a(b(x1))) b(b(x1)) -> x1 c(c(x1)) -> a(x1) graph: c#(c(x1)) -> a#(x1) -> a#(x1) -> b#(x1) b#(a(x1)) -> c#(a(b(x1))) -> c#(c(x1)) -> a#(x1) b#(a(x1)) -> b#(x1) -> b#(a(x1)) -> c#(a(b(x1))) b#(a(x1)) -> b#(x1) -> b#(a(x1)) -> a#(b(x1)) b#(a(x1)) -> b#(x1) -> b#(a(x1)) -> b#(x1) b#(a(x1)) -> a#(b(x1)) -> a#(x1) -> b#(x1) a#(x1) -> b#(x1) -> b#(a(x1)) -> c#(a(b(x1))) a#(x1) -> b#(x1) -> b#(a(x1)) -> a#(b(x1)) a#(x1) -> b#(x1) -> b#(a(x1)) -> b#(x1) Arctic Interpretation Processor: dimension: 3 interpretation: [c#](x0) = [1 0 1]x0 + [0], [b#](x0) = [1 0 0]x0, [a#](x0) = [1 0 0]x0 + [0], [0 1 0] [0 ] [c](x0) = [0 0 0]x0 + [-&] [0 0 0] [0 ], [0 0 -&] [-&] [b](x0) = [0 0 -&]x0 + [-&] [0 1 0 ] [0 ], [1 1 0 ] [0 ] [a](x0) = [0 0 -&]x0 + [-&] [0 1 0 ] [0 ] orientation: a#(x1) = [1 0 0]x1 + [0] >= [1 0 0]x1 = b#(x1) b#(a(x1)) = [2 2 1]x1 + [1] >= [1 0 0]x1 = b#(x1) b#(a(x1)) = [2 2 1]x1 + [1] >= [1 1 0]x1 + [0] = a#(b(x1)) b#(a(x1)) = [2 2 1]x1 + [1] >= [2 2 1]x1 + [1] = c#(a(b(x1))) c#(c(x1)) = [1 2 1]x1 + [1] >= [1 0 0]x1 + [0] = a#(x1) [1 1 0 ] [0 ] [0 0 -&] [-&] a(x1) = [0 0 -&]x1 + [-&] >= [0 0 -&]x1 + [-&] = b(x1) [0 1 0 ] [0 ] [0 1 0 ] [0 ] [1 1 0] [0] [1 1 0] [0] b(a(x1)) = [1 1 0]x1 + [0] >= [1 1 0]x1 + [0] = c(a(b(x1))) [1 1 0] [0] [1 1 0] [0] [0 0 -&] [-&] b(b(x1)) = [0 0 -&]x1 + [-&] >= x1 = x1 [1 1 0 ] [0 ] [1 1 1] [0] [1 1 0 ] [0 ] c(c(x1)) = [0 1 0]x1 + [0] >= [0 0 -&]x1 + [-&] = a(x1) [0 1 0] [0] [0 1 0 ] [0 ] problem: DPs: a#(x1) -> b#(x1) b#(a(x1)) -> c#(a(b(x1))) c#(c(x1)) -> a#(x1) TRS: a(x1) -> b(x1) b(a(x1)) -> c(a(b(x1))) b(b(x1)) -> x1 c(c(x1)) -> a(x1) EDG Processor: DPs: a#(x1) -> b#(x1) b#(a(x1)) -> c#(a(b(x1))) c#(c(x1)) -> a#(x1) TRS: a(x1) -> b(x1) b(a(x1)) -> c(a(b(x1))) b(b(x1)) -> x1 c(c(x1)) -> a(x1) graph: c#(c(x1)) -> a#(x1) -> a#(x1) -> b#(x1) b#(a(x1)) -> c#(a(b(x1))) -> c#(c(x1)) -> a#(x1) a#(x1) -> b#(x1) -> b#(a(x1)) -> c#(a(b(x1))) Arctic Interpretation Processor: dimension: 2 interpretation: [c#](x0) = [2 0]x0 + [0], [b#](x0) = [-& 3 ]x0 + [0], [a#](x0) = [-& 3 ]x0 + [0], [-& 2 ] [0] [c](x0) = [0 0 ]x0 + [2], [0 2 ] [0 ] [b](x0) = [-& 0 ]x0 + [-&], [0 2] [0] [a](x0) = [0 2]x0 + [2] orientation: a#(x1) = [-& 3 ]x1 + [0] >= [-& 3 ]x1 + [0] = b#(x1) b#(a(x1)) = [3 5]x1 + [5] >= [2 4]x1 + [2] = c#(a(b(x1))) c#(c(x1)) = [0 4]x1 + [2] >= [-& 3 ]x1 + [0] = a#(x1) [0 2] [0] [0 2 ] [0 ] a(x1) = [0 2]x1 + [2] >= [-& 0 ]x1 + [-&] = b(x1) [2 4] [4] [2 4] [4] b(a(x1)) = [0 2]x1 + [2] >= [0 2]x1 + [2] = c(a(b(x1))) [0 2 ] [0 ] b(b(x1)) = [-& 0 ]x1 + [-&] >= x1 = x1 [2 2] [4] [0 2] [0] c(c(x1)) = [0 2]x1 + [2] >= [0 2]x1 + [2] = a(x1) problem: DPs: a#(x1) -> b#(x1) TRS: a(x1) -> b(x1) b(a(x1)) -> c(a(b(x1))) b(b(x1)) -> x1 c(c(x1)) -> a(x1) EDG Processor: DPs: a#(x1) -> b#(x1) TRS: a(x1) -> b(x1) b(a(x1)) -> c(a(b(x1))) b(b(x1)) -> x1 c(c(x1)) -> a(x1) graph: Qed