Allow the interchange between \mid and |?

[CaptainChicky]

Hi, so for the really long spectral decomposition formula, I initially set the input

A=
\begin{pmatrix}
\mid & \mid & & \mid\\
\mathbf{v}_1 & \mathbf{v}_2 & \cdots & \mathbf{v}_n \\
\mid & \mid & & \mid
\end{pmatrix}
\begin{pmatrix}
\lambda_1&   & &  \\
 &\lambda_2 & &  \\
 &   & \ddots &  \\
 &   & &  \lambda_n
\end{pmatrix}
\begin{pmatrix}
\mid & \mid & & \mid\\
\mathbf{v}_1 & \mathbf{v}_2 & \cdots & \mathbf{v}_n \\
\mid & \mid & & \mid
\end{pmatrix}^{-1}

However, it didn't accept, much to my dismay. I checked the answer, and it seems to only accept "|" instead of the "\mid". I know "|" has less time to type, but people who first try this don't exactly know the correct answer so please accept \mid as well :) thanks

[skylee03]

My answer is exactly the same as yours except for the spaces. I tried both \mid and |, but that does not work. I found that we should write \mathbf v_n instead of \mathbf{v}_n, although the two are actually equivalent. :dizzy_face: