[texhax] The undertilde package.

[Bob Tennent]

 >|> 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
 >|please elaborate?  What *should* I have done to get access to the
 >|\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.