[Tex/LaTex] equation labels inside a nested align and aligned environment

alignlabels

I'd like to have several equations aligned pair-wise in, essentially, two columns, but with individual labels for each equation and/or for each line (where one line displays two equations).

I have achieved the desired alignments by nesting aligned environments inside an align environment. I can also label the whole align environment. What about labeling the individual equations inside the aligned environment?

I'm looking for a solution that is not too hacky, if there is one. I'm not tied to align and aligned. It may be too cluttered to number each equation, but at least I'd like to label/number each line.

Thanks!

\documentclass{article}
\usepackage{amsmath}
\begin{document}

\begin{align}
\label{eq:myeq}
\begin{aligned}[c]
%  \label{eq:myeq:AB}
   A & = B
\\ 
%  \label{eq:myeq:CD}
   C & = D
\\ 
%  \label{eq:myeq:EF}
   E & = F
\end{aligned}
\qquad \Rightarrow \qquad
\begin{aligned}[c]
%  \label{eq:myeq:ab}
   a & = b
\\   
%  \label{eq:myeq:cd}
   c & = d
\\ 
%  \label{eq:myeq:ef}
   e & = f
\,.
\end{aligned}
\end{align}

\end{document}

enter image description here

Edit: Adding info.

To see what I'm after, consider the following:

\begin{align}
\label{eq:myeq:ABab}
  A & = B &&             & a & = b 
\\ 
\label{eq:myeq:CDcd}
  C & = D && \Rightarrow & c & = d 
\\
\label{eq:myeq:EFef}
  E & = F &&             & e & = f
\end{align} 

This produces the desired result for odd-numbered equations, but not for even-numbered equations. And also I prefer to see the equations "split" as they are in my first code, as it's easier to read.

enter image description here

Best Answer

You can number each line using the alignat environment from the amsmath package.

\documentclass{article}
\usepackage{amsmath}
\begin{document}
\begin{alignat}{2}
a &= b &\quad\Rightarrow\quad c &= d \\
e &= f &  g &= h
\end{alignat}
\end{document}

alignat

You can use \nonumber to suppress numbering on individual lines. I don't think it would be a good idea to separately number the equations in the left-hand column. Readers expecting to find the equation numbers at the edge of the page are likely to find this annoying.