Hi,

I am relatively new to sublime text so maybe the problem I have is simple to solve.

Generally everything was working fine writing the Latex document until I closed and reopened sublime text.

Now I get undefined control sequence error for the code that compiled just fine 30 seconds ago.

For example in this code:

\begin{equation}

\begin{aligned}

&\mu=\sum\limit_{i=1}^N{\frac{x_i}{N}}\

&\sigma=\sqrt{\sum\limit_{i=1}^N{\frac{\left(x_i-\bar{x}\right)^2}{N}}}

\end{aligned}

\end{equation}

I get error “Undefined control sequence. [&\mu=\sum\limit]”

What can the problem be?