The package is for LaTeX , but it might still work. I notice that, in my example, the eqnarray* and align* are centered very slightly differently (the eqnarray* is less .
eqnarray vs. align. There’s a lot of freely available documentation for LaTeX, but there’s a pitfall: some documents that are still online are outdated and therefore contain obsolete information. Documents like “Obsolete packages and commands” (“l2tabu”) address the need of up-to-date information.
eqnarray and eqnarray* Similar to align and align* Not recommended because spacing is inconsistent multline and multline* First line left aligned, last line right aligned Equation number aligned vertically with first line and not centered as with other environments gather and gather* Consecutive equations without alignment flalign and flalign*.
Why not use eqnarray?. The environment eqnarray is attractive for the occasional user of mathematics in LaTeX documents: it seems to allow aligned systems of equations. Indeed it does supply such things, but it makes a serious mess of spacing. In the system.