[OS X TeX] \delimitershortfall and \delimiterfactor?

[Gary L. Gray]

This isn't specifically a Mac-related question, but I thought I might get a good answer here.

I just stumbled upon the commands \delimitershortfall and \delimiterfactor, neither of which I was previously aware. Since I typeset a lot of math with delimiters, these appear to be incredibly useful. Unfortunately, after looking in Guide to LaTeX, The LaTeX Companion, More Math Into LaTeX, and doing a bit of DuckDuckGoing, I have not been able to find anything that documents these commands (just a few examples of their use). Can anyone out there point me to a site that documents these two commands?

Thank you.

Gary