how to write double summation notation for this question

Question

I am trying to concisely write a problem as a double summation. In my problem, there are $m$ factories and each factory has $n_i$ employees ($\forall i = 1,...,m$). That is, every factory has different number of employees. So, if there are 3 factories, the factories may have 6, 7, and 10 employees.

I need to write an objective function expressing their cost minimization. I wrote this as follows:

\begin{equation} \text{min } \left(\sum_{i=1}^{m}\sum_{j=1}^{n_{i}}C_{emp_{i,j}}(t)\right) \end{equation}

Is this correct?

Answer 1

It's fine as is, but you might as well replace $C_{emp_{i,j}}$ with $C_{i,\,j}$ (I've added a space with \, viz. C_{i,\,j}) or $C_{ij}$.