16:21 - Wednesday, 23 April 2014

Automatic Equation Numbering In LyX

#Topics: numbering equations lyx

I would like to create automatic numbering of equations in LyX. when I entered


for the “equation” environment it worked. However, when trying to make the align* environment numbering


it produces errors, such as “LaTeX Error: begin{align*}undefined”.

how can I overcome this?

As LyX normally loads amsmath automatically if you use one of its environments, I just had to redefine the environment, by adding the following to the preamble:


Example of result, having added a simple align environment from the LyX menus:

enter image description here

I used the “command forms” align and endalign as I think I read somewhere on this site that those are recommended in definitions of environments. Please comment if I’m wrong.

If you still get the error message, try loading amsmath explicitly, by either

  1. adding usepackage{amsmath} the Document –> Settings –> LaTeX preamble, or
  2. going to Document –> Settings –> Math options, unchecking the box by “Use AMS math package automatically” and checking the box below, for “Use AMS math package“.

A better option, in my opinion

Instead of redefining align* to align, you can add a keyboard shortcut to add a numbered align. This is done in Tools –> Preferences –> Editing –> Shortcuts (see my answer on Shortcuts for Lemma, Claim, Theorem etc for some more detail, should that be needed). Add a new shortcut, and type

command-sequence math-mode on; math-mutate align;math-number-toggle

as the function. You could for example use Ctrl+Alt+Shift+A as the shortcut, in which case the dialog would look as follows:

enter image description here

Having done this, just hit the specified shortcut, and you have a numbered align environment.

Similarly you can create a keyboard shortcut for a numbered equation. Just replace align with equation in the function above, making it

command-sequence math-mode on; math-mutate equation;math-number-toggle

Ctrl+Alt+Shift+M is free (unless you’ve defined it yourself), so then only the Alt is the difference between a numbered and an unnumbered. You could of course change these around, making Ctrl+Shift+M create a numbered equation.