Math & Science ⇒ Alignedat padding issue

[kazza]

Hi, Ive recently been playing about with the alignedat environemnt, and have been porting my old definitions from arrays into it to allow for page breaking large equations.

But after much experimentation I can find how to cleanly remove the padding put around an alignedat environment. Ive looked at the amsmanual but no luck there.

So the following code type sets ok, but I dont like the negative space used.

Code: Select all

\begin{align*}
&\framebox[0.75\columnwidth]{left align header}\\
&\!
\begin{alignedat}{2}
 & \framebox[3em]{A} && \framebox[3em]{B}\\
 & \framebox[2em]{C} && \framebox[7em]{D}
\end{alignedat}
\end{align*}

I used to just use the array environemnt with a specifier such as {@{}l@{}} to remove padding. The manual says that the align*at environemnts allow for the horizontal spacing to be specified, but I cant see how to specificy the inital or final spaceing.