\begin{align}
    \begin{matrix}
        \mathcal{X}_{\epsilon_1}(\omega_1) & \subset & \mathcal{X}_{\epsilon_2}(\omega_1) & \subset & \cdots & \subset & \mathcal{X}_{\epsilon_n}(\omega_1), \\
        \mathcal{X}_{\epsilon_1}(\omega_2) & \subset & \mathcal{X}_{\epsilon_2}(\omega_2) & \subset & \cdots & \subset & \mathcal{X}_{\epsilon_n}(\omega_2), \\
        \vdots & \vdots &  &  &  &  & \vdots \\
        \mathcal{X}_{\epsilon_1}(\omega_T) & \subset & \mathcal{X}_{\epsilon_2}(\omega_T) & \subset & \cdots & \subset & \mathcal{X}_{\epsilon_n}(\omega_T),
    \end{matrix} \label{eq:spectral_filtration}
\end{align}
