YES Problem: f(a(),x) -> f(b(),f(c(),x)) f(a(),f(b(),x)) -> f(b(),f(a(),x)) f(d(),f(c(),x)) -> f(d(),f(a(),x)) f(a(),f(c(),x)) -> f(c(),f(a(),x)) Proof: Extended Uncurrying Processor: application symbol: f symbol table: d ==> d0/0 d1/1 c ==> c0/0 c1/1 b ==> b0/0 b1/1 a ==> a0/0 a1/1 uncurry-rules: f(a0(),x1) -> a1(x1) f(b0(),x3) -> b1(x3) f(c0(),x5) -> c1(x5) f(d0(),x7) -> d1(x7) eta-rules: problem: a1(x) -> b1(c1(x)) a1(b1(x)) -> b1(a1(x)) d1(c1(x)) -> d1(a1(x)) a1(c1(x)) -> c1(a1(x)) f(a0(),x1) -> a1(x1) f(b0(),x3) -> b1(x3) f(c0(),x5) -> c1(x5) f(d0(),x7) -> d1(x7) Matrix Interpretation Processor: dim=3 interpretation: [1 0 0] [b1](x0) = [0 0 0]x0 [0 0 0] , [1 0 1] [1 1 1] [0] [f](x0, x1) = [0 0 0]x0 + [0 0 1]x1 + [0] [0 0 0] [1 0 1] [1], [0] [a0] = [0] [0], [1 0 0] [c1](x0) = [0 0 0]x0 [0 0 0] , [1] [b0] = [0] [1], [1 0 0] [0] [d1](x0) = [0 0 0]x0 + [0] [0 0 0] [1], [1] [d0] = [0] [1], [1] [c0] = [0] [0], [1 0 0] [0] [a1](x0) = [0 0 0]x0 + [0] [1 0 0] [1] orientation: [1 0 0] [0] [1 0 0] a1(x) = [0 0 0]x + [0] >= [0 0 0]x = b1(c1(x)) [1 0 0] [1] [0 0 0] [1 0 0] [0] [1 0 0] a1(b1(x)) = [0 0 0]x + [0] >= [0 0 0]x = b1(a1(x)) [1 0 0] [1] [0 0 0] [1 0 0] [0] [1 0 0] [0] d1(c1(x)) = [0 0 0]x + [0] >= [0 0 0]x + [0] = d1(a1(x)) [0 0 0] [1] [0 0 0] [1] [1 0 0] [0] [1 0 0] a1(c1(x)) = [0 0 0]x + [0] >= [0 0 0]x = c1(a1(x)) [1 0 0] [1] [0 0 0] [1 1 1] [0] [1 0 0] [0] f(a0(),x1) = [0 0 1]x1 + [0] >= [0 0 0]x1 + [0] = a1(x1) [1 0 1] [1] [1 0 0] [1] [1 1 1] [2] [1 0 0] f(b0(),x3) = [0 0 1]x3 + [0] >= [0 0 0]x3 = b1(x3) [1 0 1] [1] [0 0 0] [1 1 1] [1] [1 0 0] f(c0(),x5) = [0 0 1]x5 + [0] >= [0 0 0]x5 = c1(x5) [1 0 1] [1] [0 0 0] [1 1 1] [2] [1 0 0] [0] f(d0(),x7) = [0 0 1]x7 + [0] >= [0 0 0]x7 + [0] = d1(x7) [1 0 1] [1] [0 0 0] [1] problem: a1(x) -> b1(c1(x)) a1(b1(x)) -> b1(a1(x)) d1(c1(x)) -> d1(a1(x)) a1(c1(x)) -> c1(a1(x)) f(a0(),x1) -> a1(x1) Matrix Interpretation Processor: dim=3 interpretation: [1 0 0] [b1](x0) = [0 0 0]x0 [0 0 0] , [1 0 0] [1 0 1] [1] [f](x0, x1) = [0 0 0]x0 + [0 1 0]x1 + [0] [0 0 0] [1 1 1] [0], [0] [a0] = [0] [0], [1 0 0] [0] [c1](x0) = [0 1 0]x0 + [1] [0 0 0] [0], [1 1 0] [d1](x0) = [0 1 0]x0 [0 0 0] , [1 0 0] [1] [a1](x0) = [0 1 0]x0 + [0] [1 1 1] [0] orientation: [1 0 0] [1] [1 0 0] a1(x) = [0 1 0]x + [0] >= [0 0 0]x = b1(c1(x)) [1 1 1] [0] [0 0 0] [1 0 0] [1] [1 0 0] [1] a1(b1(x)) = [0 0 0]x + [0] >= [0 0 0]x + [0] = b1(a1(x)) [1 0 0] [0] [0 0 0] [0] [1 1 0] [1] [1 1 0] [1] d1(c1(x)) = [0 1 0]x + [1] >= [0 1 0]x + [0] = d1(a1(x)) [0 0 0] [0] [0 0 0] [0] [1 0 0] [1] [1 0 0] [1] a1(c1(x)) = [0 1 0]x + [1] >= [0 1 0]x + [1] = c1(a1(x)) [1 1 0] [1] [0 0 0] [0] [1 0 1] [1] [1 0 0] [1] f(a0(),x1) = [0 1 0]x1 + [0] >= [0 1 0]x1 + [0] = a1(x1) [1 1 1] [0] [1 1 1] [0] problem: a1(b1(x)) -> b1(a1(x)) d1(c1(x)) -> d1(a1(x)) a1(c1(x)) -> c1(a1(x)) f(a0(),x1) -> a1(x1) Matrix Interpretation Processor: dim=1 interpretation: [b1](x0) = x0, [f](x0, x1) = 5x0 + 4x1 + 3, [a0] = 4, [c1](x0) = x0 + 6, [d1](x0) = 2x0 + 1, [a1](x0) = x0 + 6 orientation: a1(b1(x)) = x + 6 >= x + 6 = b1(a1(x)) d1(c1(x)) = 2x + 13 >= 2x + 13 = d1(a1(x)) a1(c1(x)) = x + 12 >= x + 12 = c1(a1(x)) f(a0(),x1) = 4x1 + 23 >= x1 + 6 = a1(x1) problem: a1(b1(x)) -> b1(a1(x)) d1(c1(x)) -> d1(a1(x)) a1(c1(x)) -> c1(a1(x)) Matrix Interpretation Processor: dim=1 interpretation: [b1](x0) = 2x0 + 4, [c1](x0) = 4x0 + 1, [d1](x0) = 2x0 + 1, [a1](x0) = x0 orientation: a1(b1(x)) = 2x + 4 >= 2x + 4 = b1(a1(x)) d1(c1(x)) = 8x + 3 >= 2x + 1 = d1(a1(x)) a1(c1(x)) = 4x + 1 >= 4x + 1 = c1(a1(x)) problem: a1(b1(x)) -> b1(a1(x)) a1(c1(x)) -> c1(a1(x)) Matrix Interpretation Processor: dim=3 interpretation: [1 0 1] [0] [b1](x0) = [0 1 0]x0 + [1] [0 1 0] [1], [1 0 1] [1] [c1](x0) = [0 1 0]x0 + [0] [0 1 0] [0], [1 0 1] [a1](x0) = [0 1 0]x0 [0 1 0] orientation: [1 1 1] [1] [1 1 1] [0] a1(b1(x)) = [0 1 0]x + [1] >= [0 1 0]x + [1] = b1(a1(x)) [0 1 0] [1] [0 1 0] [1] [1 1 1] [1] [1 1 1] [1] a1(c1(x)) = [0 1 0]x + [0] >= [0 1 0]x + [0] = c1(a1(x)) [0 1 0] [0] [0 1 0] [0] problem: a1(c1(x)) -> c1(a1(x)) Matrix Interpretation Processor: dim=3 interpretation: [1 0 0] [0] [c1](x0) = [0 1 0]x0 + [1] [0 0 0] [0], [1 1 0] [a1](x0) = [0 1 0]x0 [0 0 0] orientation: [1 1 0] [1] [1 1 0] [0] a1(c1(x)) = [0 1 0]x + [1] >= [0 1 0]x + [1] = c1(a1(x)) [0 0 0] [0] [0 0 0] [0] problem: Qed