[Tex/LaTex] Subequations with main equation number


I would like to have a set of equations, all under the same number, but with a "main" equation, and some other equations that follow being labelled with subnumbers, for example

1 = 1 (1)

1 < 2 (1a)

1 > 0 (1b)

How can I achieve this?

Best Answer

Use \tag for getting the main number:



First some separate equations
1=1 \tag{\ref{first:main}}
and another
1>0 \label{first:a}
and another
1<2 \label{first:b}

But it works also with \texttt{align} and the other alignment
1 &= 1 \tag{\ref{second:main}}\\
1 &> 0 \label{second:a}\\
1 &< 2 \label{second:b}
and you can reference all of them, as seen below.

Here are some references: \eqref{first:main}, \eqref{first:a}
and \eqref{second:b}.


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