# [texhax] The undertilde package.

Bob Tennent rdt at cs.queensu.ca
Sat May 10 01:07:47 CEST 2014

>|> I'm wrong. It is undertilde.tex. Why did you think it was an sty
>|> file?
>|
>|Well ... I guess the short answer is I didn't.  I just wanted to use
>|\utilde, found it was provided by the package "undertilde" and so put
>|\usepackage{undertilde} in my preamble.  (Isn't that what one usually
>|does in respect of packages?)
>|
>|But this produced the error "package undertilde not found" (or words to
>|that effect).
>|
>|There *is* a .sty file in the undertilde package which I downloaded from
>|CRAN and managed to install.  After I installed it, there was no longer
>|any problem with \usepackage{undertilde}.
>|
>|So I am kind of bewildered as to what you are driving at.  Can you
>|\utilde command (without having to install "undertilde" by hand as it
>|were.  And why wasn't undertilde.sty available from the get-go from my
>|installation of Texlive 2013?

If you use

\usepackage{xxx}

LaTeX expects to find xxx.sty. But undertilde in TeXLive is a
"generic" package, usable with Plain TeX, so it's been named
undertilde.tex and it's loaded by using

\input{undertilde}

The undertilde.tex in TeXLive is likely from

http://www.ctan.org/pkg/undertilde-gen

The undertilde package available at

http://www.ctan.org/pkg/undertilde

seems to be different.

Bob T.