[texhax] 3x3 array of alighned equations

[Robin Fairbairns]

> The alignat environment works a treat except now I'd like to get the subequation numbering working.
> Something I've tried:
> 
> \begin{alignat}
> \renewcommand{\theequation}{\arabic{equation}a,b,c}
> a&=b & &=c & &=d\\
> a&=bbbb & &=c & &=d\\
> a&=bb & &=c & &=d
> \end{alignat}
> 
> but this gets ignored and produces the standard (1), (2), (3) on consecutive lines.
> What actually I want is (1a,b,c), (1d,e,f), (1g,h,i) on consecutive lines.
> The above trick does work in the equation environment but perhaps the the command "theequation" isn't used in alignat?

amsmath does its labelling in its own enigmatic way.

try

\begin{alignat}
a&=b & &=c & &=d \tag{\theequation a,b,c}\\
a&=bbbb & &=c & &=d \tag{\theequation d,e,f}\\
a&=bb & &=c & &=d \tag{\theequation h,h,i}
\end{alignat}