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Maybe the problem is related to my version of Linux Libertine fonts? I'm using version 4.4.1-4 from Ubuntu 10.04 repository.<BR>
It seems to be the OpenType version, because I need to specify "Linux Libertine O" to find the fonts.<BR>
<BR>
So modifying your test document accordingly:<BR>
<BR>
% !TEX TS-program = XeLaTeX
<PRE>
\listfiles
\documentclass{article}
\usepackage{fontspec}
\setmainfont{Linux Libertine O}
\begin{document}
P\textsubscript{\textepsilon}
\end{document}
And running xelatex on it:
This is XeTeX, Version 3.1415926-2.2-0.9997.4 (TeX Live 2010):
[...]
(/usr/local/texlive/2010/texmf-dist/tex/latex/base/article.cls
Document Class: article 2007/10/19 v1.4h Standard LaTeX document class
(/usr/local/texlive/2010/texmf-dist/tex/latex/base/size10.clo))
(/usr/local/texlive/2010/texmf-dist/tex/latex/fontspec/fontspec.sty
(/usr/local/texlive/2010/texmf-dist/tex/latex/expl3/expl3.sty
(/usr/local/texlive/2010/texmf-dist/tex/latex/expl3/l3names.sty)
(/usr/local/texlive/2010/texmf-dist/tex/latex/etex-pkg/etex.sty)
(/usr/local/texlive/2010/texmf-dist/tex/latex/expl3/l3basics.sty)
(/usr/local/texlive/2010/texmf-dist/tex/latex/expl3/l3expan.sty)
(/usr/local/texlive/2010/texmf-dist/tex/latex/expl3/l3tl.sty)
(/usr/local/texlive/2010/texmf-dist/tex/latex/expl3/l3intexpr.sty)
(/usr/local/texlive/2010/texmf-dist/tex/latex/expl3/l3quark.sty)
(/usr/local/texlive/2010/texmf-dist/tex/latex/expl3/l3seq.sty)
(/usr/local/texlive/2010/texmf-dist/tex/latex/expl3/l3toks.sty)
(/usr/local/texlive/2010/texmf-dist/tex/latex/expl3/l3int.sty)
(/usr/local/texlive/2010/texmf-dist/tex/latex/expl3/l3prg.sty)
(/usr/local/texlive/2010/texmf-dist/tex/latex/expl3/l3clist.sty)
(/usr/local/texlive/2010/texmf-dist/tex/latex/expl3/l3token.sty)
(/usr/local/texlive/2010/texmf-dist/tex/latex/expl3/l3prop.sty)
(/usr/local/texlive/2010/texmf-dist/tex/latex/expl3/l3msg.sty)
(/usr/local/texlive/2010/texmf-dist/tex/latex/expl3/l3io.sty)
(/usr/local/texlive/2010/texmf-dist/tex/latex/expl3/l3skip.sty)
(/usr/local/texlive/2010/texmf-dist/tex/latex/expl3/l3box.sty)
(/usr/local/texlive/2010/texmf-dist/tex/latex/expl3/l3keyval.sty)
(/usr/local/texlive/2010/texmf-dist/tex/latex/expl3/l3keys.sty)
(/usr/local/texlive/2010/texmf-dist/tex/latex/expl3/l3precom.sty)
(/usr/local/texlive/2010/texmf-dist/tex/latex/expl3/l3xref.sty)
(/usr/local/texlive/2010/texmf-dist/tex/latex/expl3/l3file.sty)
(/usr/local/texlive/2010/texmf-dist/tex/latex/expl3/l3fp.sty)
(/usr/local/texlive/2010/texmf-dist/tex/latex/tools/calc.sty))
(/usr/local/texlive/2010/texmf-dist/tex/latex/xpackages/xbase/xparse.sty)
(/usr/local/texlive/2010/texmf-dist/tex/generic/kastrup/binhex.tex)
(/usr/local/texlive/2010/texmf-dist/tex/latex/xkeyval/xkeyval.sty
(/usr/local/texlive/2010/texmf-dist/tex/generic/xkeyval/xkeyval.tex
(/usr/local/texlive/2010/texmf-dist/tex/generic/xkeyval/keyval.tex)))
(/usr/local/texlive/2010/texmf-dist/tex/latex/fontspec/fontspec-patches.sty
(/usr/local/texlive/2010/texmf-dist/tex/latex/base/fixltx2e.sty))
(/usr/local/texlive/2010/texmf-dist/tex/latex/base/fontenc.sty
(/usr/local/texlive/2010/texmf-dist/tex/latex/euenc/eu1enc.def)
(/usr/local/texlive/2010/texmf-dist/tex/latex/euenc/eu1lmr.fd))
fontspec.cfg loaded.
<B>(/usr/local/texlive/2010/texmf-dist/tex/latex/fontspec/fontspec.cfg))</B>
<B>(./lowercase_test.aux)</B>
<B>! Undefined control sequence.</B>
<B><argument> ...f@size \z@ \selectfont \textepsilon</B>
So the problem seems to be coming from fontspec. What does it mean? That it cannot find \textepsilon for my font?
Thanks,
Maxim
</PRE>
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