Math & Science ⇒ Left alignment in subequations

[nvx]

Hello everyone,

Is it possible to typeset a matrix of four left-aligned equations using the subequations environment? The only thing I am able to get is

Code: Select all

[looong 1st equation]  [short note on 1st eqn]            (1a)
      [short 2nd eqn]  [longer note on 2nd equation]      (1b)

instead of

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[looong 1st equation]  [short note on 1st eqn]            (1a)
[short 3rd eqn]        [longer note on 2nd equation]      (1b)

The reason I would like to align the equations this way is that I use left-aligned equations throughout the entire document (\documentclass[...,fleqn]{...}). MWE follows:

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\documentclass[12pt,a4paper,english,fleqn]{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{babel}
\usepackage{amsmath}
\begin{document}
\begin{subequations}
\begin{align}
looong 1st equation & \qquad short note on 1st eqn\\
short 3rd eqn & \qquad longer note on 2nd equation
\end{align}
\end{subequations}
\end{document}

I also tried to experiment with alignat, but that did not do what I need either. Array, on the other hand, aligned the stuff as required, but equation numbers were no longer present.

Any help would be much appreciated.

nvx

[nvx]

Well, I sort of found how to do it, but it is far from elegant:

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\begin{subequations}
\begin{alignat}{3}
\! & looong 1st equation & \qquad & short note on 1st eqn \\
\! & short 3rd eqn & \qquad & longer note on 2nd equation
\end{alignat}
\end{subequations}

(\! is there to more or less compensate for the extra space added by the empty first column.)

If anyone knows a better solution, please, let me know.