YES O(n^5) TRS: { implies(x, or(y, z)) -> or(y, implies(x, z)), implies(not(x), y) -> or(x, y), implies(not(x), or(y, z)) -> implies(y, or(x, z)) } DUP: We consider a non-duplicating system. Trs: { implies(x, or(y, z)) -> or(y, implies(x, z)), implies(not(x), y) -> or(x, y), implies(not(x), or(y, z)) -> implies(y, or(x, z)) } Matrix Interpretation: Interpretation class: triangular [X4] [1 0 0 0 0][X4] [1] [X3] [0 0 0 0 0][X3] [0] [not]([X2]) = [0 0 0 0 0][X2] + [0] [X1] [0 0 0 0 0][X1] [0] [X0] [0 0 0 0 0][X0] [0] [X9] [X4] [1 0 0 0 0][X9] [1 1 0 0 0][X4] [0] [X8] [X3] [0 0 0 0 0][X8] [0 1 0 0 0][X3] [1] [implies]([X7], [X2]) = [0 0 0 0 0][X7] + [0 0 0 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 0][X5] [0 0 0 0 0][X0] [0] [X9] [X4] [1 0 0 0 0][X9] [1 0 0 0 0][X4] [0] [X8] [X3] [0 0 0 0 0][X8] [0 1 0 0 0][X3] [1] [or]([X7], [X2]) = [0 0 0 0 0][X7] + [0 0 0 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 0][X5] [0 0 0 0 0][X0] [0] Qed