2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/168297Let M_n be the collection of n x n complex matrices equipped with operator norm. Suppose U, V \in M_n are two unitary matrices, each possessing a gap larger than Δin their spectrum, which satisfy ||UV-VU|| \le ε. Then it is shown that there are two unitary operators X and Y satisfying XY-YX = 0 and ||U-X|| + ||V-Y|| \le E(Δ^2/ε) (ε/Δ^2)^(1/6), where E(x) is a function growing slower than x^(1/k) for any positive integer k.5 pagesOperator AlgebrasMathematical PhysicsQuantum Physics15A15, 15A27, 47A55; 47B47text