I am writing a lengthy paper. So far I have been using \label{...} and \eqref{...}.
This makes the counter of the referenced equations to be increased by one across all sections and subsections.
But what I want, is that the counter of the references equations begins with the associated section and subsection number.
\numberwithin{equation}{section}? For it you need to loadamsmathpackage. – Zarko Apr 04 '21 at 07:36