YES O(n^5) TRS: {app(app(app(uncurry(), f), x), y) -> app(app(f, x), y)} DUP: We consider a non-duplicating system. Trs: {app(app(app(uncurry(), f), x), y) -> app(app(f, x), y)} Matrix Interpretation: Interpretation class: triangular [0] [0] [uncurry] = [0] [0] [1] [X9] [X4] [1 0 0 0 1][X9] [1 0 0 0 0][X4] [0] [X8] [X3] [0 1 1 0 0][X8] [0 1 1 0 0][X3] [0] [app]([X7], [X2]) = [0 0 0 0 0][X7] + [0 0 1 0 0][X2] + [0] [X6] [X1] [0 0 0 0 0][X6] [0 0 0 0 0][X1] [0] [X5] [X0] [0 0 0 0 1][X5] [0 0 0 0 1][X0] [1] Qed