Meaning of $\begin{bmatrix}V \\ \begin{bmatrix} E^p \\ E^n \end{bmatrix} \end{bmatrix}$, for matrices $V$, $E^p$, $E^n$

Question

What does this notation mean:

$$ \tilde{V} = \begin{bmatrix}V \\ \begin{bmatrix} E^p \\ E^n \end{bmatrix} \end{bmatrix} $$

where $V$ is an $k \times n$ matrix and both $E^p$, $E^n$ are $m\times n$ matrices. Does this just stack them vertically to form a $(k + 2m) \times n$ matrix?

Source is from this paper (introduced on page 2): https://projet.liris.cnrs.fr/imagine/pub/proceedings/ICIP-2014/Papers/1569911469.pdf