[texhax] 3x3 array of alighned equations

Novak Elliott N.S.J.Elliott at warwick.ac.uk
Thu Nov 3 17:28:29 CET 2005


The alignat environment works a treat except now I'd like to get the subequation numbering working.
Something I've tried:

a&=b & &=c & &=d\\
a&=bbbb & &=c & &=d\\
a&=bb & &=c & &=d

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?

Any suggestions would be much appreciated.


>>> Lars Madsen <daleif at imf.au.dk> 11/02/05 12:43pm >>>
Novak Elliott :

> Hi,
> I'd like to format a 3x3 array of subequations in the form:
> a11 = b,         a12 = c,    a13 = d             (1a,b,c)
>                                                  -
>                                                  e
> a21 = f,    3 x a22 = ...                             (1d,e,f)
>          -
>          g
> a22 = ..                                                     (1g,h,i)
> i.e. I want them aligned horizontally between the three columns and also I want them aligned to the = sign within each column.  So I effectively have 9 columns, or 3 columns each with 3 subcolumns.  The eqnarry environment only allows the alignment to work with one equation per line, and the array environment typesets fractions in a tiny font so that they fit within one text line.  However, I want them to be at full size like in an ordinary equation.  I have a hack for getting the subequation numbering to work without using the subequations environment so that shouldn't be a drama.  If there is a way to produce an array that allows left/centre/right alignment and also allows fractions to be typeset at full size then that would almost certainly work.

the amsmath package and the alignat env might help

\begin{alignat*}{3} % three alignments
  a&=b & &=c & &=d\\
  a&=bbbb & &=c & &=d\\
  a&=bb & &=c & &=d

there needs to be 2n-1 &'s in each line, where n is the number of 
alignments, the extra two &'s in the example above separates the 


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