YES Problem: f(a(),f(a(),x)) -> f(c(),f(b(),x)) f(b(),f(b(),x)) -> f(a(),f(c(),x)) f(c(),f(c(),x)) -> f(b(),f(a(),x)) Proof: Extended Uncurrying Processor: application symbol: f symbol table: b ==> b0/0 b1/1 c ==> c0/0 c1/1 a ==> a0/0 a1/1 uncurry-rules: f(a0(),x1) -> a1(x1) f(c0(),x3) -> c1(x3) f(b0(),x5) -> b1(x5) eta-rules: problem: a1(a1(x)) -> c1(b1(x)) b1(b1(x)) -> a1(c1(x)) c1(c1(x)) -> b1(a1(x)) f(a0(),x1) -> a1(x1) f(c0(),x3) -> c1(x3) f(b0(),x5) -> b1(x5) Matrix Interpretation Processor: dim=3 interpretation: [1] [a0] = [0] [0], [0] [b0] = [0] [0], [1 0 0] [1 1 1] [0] [f](x0, x1) = [0 0 0]x0 + [1 0 1]x1 + [1] [0 0 1] [1 1 0] [0], [1 1 0] [0] [a1](x0) = [0 0 0]x0 + [1] [0 0 0] [0], [1 1 0] [0] [c1](x0) = [0 0 0]x0 + [1] [0 0 0] [0], [1 1 0] [0] [b1](x0) = [0 0 0]x0 + [1] [0 0 0] [0], [0] [c0] = [0] [1] orientation: [1 1 0] [1] [1 1 0] [1] a1(a1(x)) = [0 0 0]x + [1] >= [0 0 0]x + [1] = c1(b1(x)) [0 0 0] [0] [0 0 0] [0] [1 1 0] [1] [1 1 0] [1] b1(b1(x)) = [0 0 0]x + [1] >= [0 0 0]x + [1] = a1(c1(x)) [0 0 0] [0] [0 0 0] [0] [1 1 0] [1] [1 1 0] [1] c1(c1(x)) = [0 0 0]x + [1] >= [0 0 0]x + [1] = b1(a1(x)) [0 0 0] [0] [0 0 0] [0] [1 1 1] [1] [1 1 0] [0] f(a0(),x1) = [1 0 1]x1 + [1] >= [0 0 0]x1 + [1] = a1(x1) [1 1 0] [0] [0 0 0] [0] [1 1 1] [0] [1 1 0] [0] f(c0(),x3) = [1 0 1]x3 + [1] >= [0 0 0]x3 + [1] = c1(x3) [1 1 0] [1] [0 0 0] [0] [1 1 1] [0] [1 1 0] [0] f(b0(),x5) = [1 0 1]x5 + [1] >= [0 0 0]x5 + [1] = b1(x5) [1 1 0] [0] [0 0 0] [0] problem: a1(a1(x)) -> c1(b1(x)) b1(b1(x)) -> a1(c1(x)) c1(c1(x)) -> b1(a1(x)) f(c0(),x3) -> c1(x3) f(b0(),x5) -> b1(x5) Matrix Interpretation Processor: dim=1 interpretation: [b0] = 2, [f](x0, x1) = 4x0 + 4x1, [a1](x0) = 3x0 + 3, [c1](x0) = 3x0 + 3, [b1](x0) = 3x0 + 3, [c0] = 6 orientation: a1(a1(x)) = 9x + 12 >= 9x + 12 = c1(b1(x)) b1(b1(x)) = 9x + 12 >= 9x + 12 = a1(c1(x)) c1(c1(x)) = 9x + 12 >= 9x + 12 = b1(a1(x)) f(c0(),x3) = 4x3 + 24 >= 3x3 + 3 = c1(x3) f(b0(),x5) = 4x5 + 8 >= 3x5 + 3 = b1(x5) problem: a1(a1(x)) -> c1(b1(x)) b1(b1(x)) -> a1(c1(x)) c1(c1(x)) -> b1(a1(x)) DP Processor: DPs: a{1,#}(a1(x)) -> b{1,#}(x) a{1,#}(a1(x)) -> c{1,#}(b1(x)) b{1,#}(b1(x)) -> c{1,#}(x) b{1,#}(b1(x)) -> a{1,#}(c1(x)) c{1,#}(c1(x)) -> a{1,#}(x) c{1,#}(c1(x)) -> b{1,#}(a1(x)) TRS: a1(a1(x)) -> c1(b1(x)) b1(b1(x)) -> a1(c1(x)) c1(c1(x)) -> b1(a1(x)) TDG Processor: DPs: a{1,#}(a1(x)) -> b{1,#}(x) a{1,#}(a1(x)) -> c{1,#}(b1(x)) b{1,#}(b1(x)) -> c{1,#}(x) b{1,#}(b1(x)) -> a{1,#}(c1(x)) c{1,#}(c1(x)) -> a{1,#}(x) c{1,#}(c1(x)) -> b{1,#}(a1(x)) TRS: a1(a1(x)) -> c1(b1(x)) b1(b1(x)) -> a1(c1(x)) c1(c1(x)) -> b1(a1(x)) graph: c{1,#}(c1(x)) -> b{1,#}(a1(x)) -> b{1,#}(b1(x)) -> a{1,#}(c1(x)) c{1,#}(c1(x)) -> b{1,#}(a1(x)) -> b{1,#}(b1(x)) -> c{1,#}(x) c{1,#}(c1(x)) -> a{1,#}(x) -> a{1,#}(a1(x)) -> c{1,#}(b1(x)) c{1,#}(c1(x)) -> a{1,#}(x) -> a{1,#}(a1(x)) -> b{1,#}(x) b{1,#}(b1(x)) -> c{1,#}(x) -> c{1,#}(c1(x)) -> b{1,#}(a1(x)) b{1,#}(b1(x)) -> c{1,#}(x) -> c{1,#}(c1(x)) -> a{1,#}(x) b{1,#}(b1(x)) -> a{1,#}(c1(x)) -> a{1,#}(a1(x)) -> c{1,#}(b1(x)) b{1,#}(b1(x)) -> a{1,#}(c1(x)) -> a{1,#}(a1(x)) -> b{1,#}(x) a{1,#}(a1(x)) -> c{1,#}(b1(x)) -> c{1,#}(c1(x)) -> b{1,#}(a1(x)) a{1,#}(a1(x)) -> c{1,#}(b1(x)) -> c{1,#}(c1(x)) -> a{1,#}(x) a{1,#}(a1(x)) -> b{1,#}(x) -> b{1,#}(b1(x)) -> a{1,#}(c1(x)) a{1,#}(a1(x)) -> b{1,#}(x) -> b{1,#}(b1(x)) -> c{1,#}(x) Bounds Processor: bound: 0 enrichment: match automaton: final states: {13,12,11,9,8,6,5,3,1} transitions: a{1,0}(7) -> 12* a{1,0}(2) -> 10* f130() -> 2* c{1,#,0}(2) -> 5* c{1,#,0}(4) -> 3* b{1,0}(2) -> 4* b{1,0}(10) -> 13* c{1,0}(4) -> 11* c{1,0}(2) -> 7* a{1,#,0}(7) -> 6* a{1,#,0}(2) -> 8* b{1,#,0}(10) -> 9* b{1,#,0}(2) -> 1* 12 -> 4* 11 -> 10* 6 -> 1* 13 -> 7* 8 -> 5* 1 -> 8* 5 -> 1* 9 -> 5* 3 -> 8* problem: DPs: TRS: a1(a1(x)) -> c1(b1(x)) b1(b1(x)) -> a1(c1(x)) c1(c1(x)) -> b1(a1(x)) Qed