YES Problem: a(x1) -> x1 a(b(x1)) -> b(b(a(a(c(x1))))) b(b(x1)) -> x1 c(c(x1)) -> x1 Proof: DP Processor: DPs: a#(b(x1)) -> c#(x1) a#(b(x1)) -> a#(c(x1)) a#(b(x1)) -> a#(a(c(x1))) a#(b(x1)) -> b#(a(a(c(x1)))) a#(b(x1)) -> b#(b(a(a(c(x1))))) TRS: a(x1) -> x1 a(b(x1)) -> b(b(a(a(c(x1))))) b(b(x1)) -> x1 c(c(x1)) -> x1 TDG Processor: DPs: a#(b(x1)) -> c#(x1) a#(b(x1)) -> a#(c(x1)) a#(b(x1)) -> a#(a(c(x1))) a#(b(x1)) -> b#(a(a(c(x1)))) a#(b(x1)) -> b#(b(a(a(c(x1))))) TRS: a(x1) -> x1 a(b(x1)) -> b(b(a(a(c(x1))))) b(b(x1)) -> x1 c(c(x1)) -> x1 graph: a#(b(x1)) -> a#(c(x1)) -> a#(b(x1)) -> b#(b(a(a(c(x1))))) a#(b(x1)) -> a#(c(x1)) -> a#(b(x1)) -> b#(a(a(c(x1)))) a#(b(x1)) -> a#(c(x1)) -> a#(b(x1)) -> a#(a(c(x1))) a#(b(x1)) -> a#(c(x1)) -> a#(b(x1)) -> a#(c(x1)) a#(b(x1)) -> a#(c(x1)) -> a#(b(x1)) -> c#(x1) a#(b(x1)) -> a#(a(c(x1))) -> a#(b(x1)) -> b#(b(a(a(c(x1))))) a#(b(x1)) -> a#(a(c(x1))) -> a#(b(x1)) -> b#(a(a(c(x1)))) a#(b(x1)) -> a#(a(c(x1))) -> a#(b(x1)) -> a#(a(c(x1))) a#(b(x1)) -> a#(a(c(x1))) -> a#(b(x1)) -> a#(c(x1)) a#(b(x1)) -> a#(a(c(x1))) -> a#(b(x1)) -> c#(x1) SCC Processor: #sccs: 1 #rules: 2 #arcs: 10/25 DPs: a#(b(x1)) -> a#(c(x1)) a#(b(x1)) -> a#(a(c(x1))) TRS: a(x1) -> x1 a(b(x1)) -> b(b(a(a(c(x1))))) b(b(x1)) -> x1 c(c(x1)) -> x1 Arctic Interpretation Processor: dimension: 2 interpretation: [a#](x0) = [-& 0 ]x0 + [0], [0 0 ] [c](x0) = [0 -&]x0, [0 -&] [0] [b](x0) = [2 0 ]x0 + [3], [0 0 ] [0 ] [a](x0) = [-& 2 ]x0 + [-&] orientation: a#(b(x1)) = [2 0]x1 + [3] >= [0 -&]x1 + [0] = a#(c(x1)) a#(b(x1)) = [2 0]x1 + [3] >= [2 -&]x1 + [0] = a#(a(c(x1))) [0 0 ] [0 ] a(x1) = [-& 2 ]x1 + [-&] >= x1 = x1 [2 0] [3] [2 0] [0] a(b(x1)) = [4 2]x1 + [5] >= [4 2]x1 + [3] = b(b(a(a(c(x1))))) [0 -&] [0] b(b(x1)) = [2 0 ]x1 + [3] >= x1 = x1 [0 0] c(c(x1)) = [0 0]x1 >= x1 = x1 problem: DPs: a#(b(x1)) -> a#(a(c(x1))) TRS: a(x1) -> x1 a(b(x1)) -> b(b(a(a(c(x1))))) b(b(x1)) -> x1 c(c(x1)) -> x1 EDG Processor: DPs: a#(b(x1)) -> a#(a(c(x1))) TRS: a(x1) -> x1 a(b(x1)) -> b(b(a(a(c(x1))))) b(b(x1)) -> x1 c(c(x1)) -> x1 graph: a#(b(x1)) -> a#(a(c(x1))) -> a#(b(x1)) -> a#(a(c(x1))) Arctic Interpretation Processor: dimension: 4 interpretation: [a#](x0) = [0 -2 1 0 ]x0 + [0], [-& 0 -& -&] [0 ] [0 -1 1 1 ] [-&] [c](x0) = [-& -1 -& -&]x0 + [-&] [-& -1 -& -&] [-2], [-& 0 -& -&] [1 ] [0 -& 0 -&] [0 ] [b](x0) = [-& 0 -& -&]x0 + [0 ] [-1 0 0 0 ] [-&], [0 -& 1 -&] [0 ] [0 0 0 1 ] [0 ] [a](x0) = [-2 -& 0 0 ]x0 + [-1] [0 -& 0 1 ] [0 ] orientation: a#(b(x1)) = [-1 1 0 0 ]x1 + [1] >= [-2 0 -1 -1]x1 + [0] = a#(a(c(x1))) [0 -& 1 -&] [0 ] [0 0 0 1 ] [0 ] a(x1) = [-2 -& 0 0 ]x1 + [-1] >= x1 = x1 [0 -& 0 1 ] [0 ] [-& 1 -& -&] [1] [-& 0 -& -&] [1] [0 1 1 1 ] [1] [0 1 1 1 ] [1] a(b(x1)) = [-1 0 0 0 ]x1 + [0] >= [-& 0 -& -&]x1 + [0] = b(b(a(a(c(x1))))) [0 1 1 1 ] [1] [0 1 1 1 ] [1] [0 -& 0 -&] [1] [-& 0 -& -&] [1] b(b(x1)) = [0 -& 0 -&]x1 + [0] >= x1 = x1 [0 0 0 0 ] [0] [0 -1 1 1 ] [0 ] [-1 0 0 0 ] [0 ] c(c(x1)) = [-1 -2 0 0 ]x1 + [-&] >= x1 = x1 [-1 -2 0 0 ] [-2] problem: DPs: TRS: a(x1) -> x1 a(b(x1)) -> b(b(a(a(c(x1))))) b(b(x1)) -> x1 c(c(x1)) -> x1 Qed