Take the 2-minute tour ×
TeX - LaTeX Stack Exchange is a question and answer site for users of TeX, LaTeX, ConTeXt, and related typesetting systems. It's 100% free, no registration required.

Is there a way to force individual equations to place their equation numbers (or more specifically the result of a \tag*{blah}) on a specific side of the page regardless of the options to amsart.

I sometimes wish to use the equation enviornment to define 'requirements' in my papers which should look like:

R_e: equation stuff

Where R_e is the equation tag. R_e should be on the left even when reqno is passed to the documentclass. How can I accomplish this?

share|improve this question

1 Answer 1

up vote 8 down vote accepted

If you just want to do this for the equation environment, define a command to be used in the equation environment:

\newcommand{\LeftEqNo}{\let\veqno\@@leqno}

For instance,

\documentclass{article}
\usepackage{amsmath}
\makeatletter
\newcommand{\LeftEqNo}{\let\veqno\@@leqno}
\makeatother
\begin{document}
  \begin{equation}
    x^2 + y^2 = 1,
  \end{equation}
  \begin{equation}\LeftEqNo
    x^2 + y^2 = 1.
  \end{equation}
\end{document}

The align environment is implemented quite differently, and you will need the environ package used like

\usepackage{environ}
\makeatletter
\NewEnviron{Lalign}{\tagsleft@true\begin{align}\BODY\end{align}}
\makeatother

Then use \begin{Lalign} ... \end{Lalign} for left-numbered align environments.

I'm afraid that various hacks of the same kind will be necessary for the other ams environments, but I can't list everything without knowing which ones you need :).

share|improve this answer
    
equation or possibly align is fine. I plan to wrap this in a special environment for this construct and it will be one of those two. –  Peter Gerdes Jan 2 '11 at 0:18
    
When I try this (using pdflatex) I get an error: ! Undefined control sequence. \env@Lalign@process ->\tagsleft –  Sam Nead Sep 9 '11 at 14:59
    
@Sam Nead: I assume you might have a different version of the environ package. Can you post somewhere the result of \listfiles? –  Bruno Le Floch Sep 11 '11 at 17:17
    
Using the command \LeftEqNo in equation as above, LaTeX reports the error "ERROR: You can't use `\spacefactor' in display math mode." and "\veqno ->\spacefactor \@m l.1567 \end{equation}". What is wrong? –  gofvonx Feb 6 at 10:16
1  
@gofvonx I've updated with a full example. I had forgotten to mention the need for \makeatletter and \makeother when one works with commands whose name contains @. –  Bruno Le Floch Feb 7 at 22:32

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.