The code is below. I want B to be printed without brackets arround since it is just one vector element. 

```
\begin{equation}
Y = 
  \begin{bmatrix}
    \textit{\textbf{t}}_{1} \\
    \textit{\textbf{t}}_{2} \\
    \textit{\textbf{t}}_{3} \\
    \textit{\textbf{t}}_{4} \\
  \end{bmatrix}
 \begin{bmatrix}
    \textit{\textbf{B}}
  \end{bmatrix}
 \end{equation}

```