# SPAM:[texhax] Renewcommand not working for \Lambda and \Sigma

Philip G. Ratcliffe philip.ratcliffe at uninsubria.it
Tue Nov 29 17:21:40 CET 2005

> I would like to redefine the capital Greek letters so that they can be
used
> without worrying about putting \$ around them in in-line text. I was able
to
> do this fine for all letters

This is news to me; maybe you could tell us how you did it for the letters
you say worked ... or do you really only mean things like the following?

\newcommand{\Alpha}{\ensuremath A\xspace}

> except for \Lambda and \Sigma (uppercase). The following is the code I
used
> in the preamble of my document.
>
> \renewcommand{\Lambda}{\ensuremath \Lambda\xspace}
> \renewcommand{\Sigma}{\ensuremath\Sigma\xspace}
>
> What happens is that my LaTeX hits waht appears to be an infinite loop and
> then runs out of memory and then shuts down.

Not surprising really is it?

> Any thoughts on why \Lambda and \Sigma are the only ones (upper or lower
case)
> that are giving me such trouble?

I don't believe they are - that is, on my setup (MiKTeX) ANY such
definitions
run into the obvious loop problem.

The standard way to get round this is, e.g.:

\let\oldSigma\Sigma
\renewcommand{\Sigma}{\ensuremath\oldSigma\xspace}

Cheers,  Phil Ratcliffe