What input encoding do I have to choose if I have an 'ɛ' in a reference title?

Question

I'm trying to cite this paper in my assignment using bibtex. It has an 'ɛ' in the title and this does not get represented correctly in my pdf. Umlauts, which I also have, are not a problem.

So far I've tried

\usepackage[utf8]{inputenc}

and

\usepackage[latin1]{inputenc}

but pdflatex asks for an interpretation in both cases.

I'm using jabref to manage my .bib file and there the ɛ is encoded as É^Û when I open it with nano.

Is there a way to solve this without using the method described in this question? It works, but I would not want to have an expression like {$\varepsilon$} in jabref.

locale returns:

    LANG=
    LC_CTYPE="POSIX"
    LC_NUMERIC="POSIX"
    LC_TIME="POSIX"
    LC_COLLATE="POSIX"
    LC_MONETARY="POSIX"
    LC_MESSAGES="POSIX"
    LC_PAPER="POSIX"
    LC_NAME="POSIX"
    LC_ADDRESS="POSIX"
    LC_TELEPHONE="POSIX"
    LC_MEASUREMENT="POSIX"
    LC_IDENTIFICATION="POSIX"
    LC_ALL=

Correction:

The umlauts only work with utf8 encoding.

It is hard to answer as the character in the question is a latin letter U+025b LATIN SMALL LETTER OPEN E, but you suggest that \varepsilon would work, but that is Greek, even though it may looks superficially similar. What character do you actually need (and should it be in math or text) — David Carlisle, Nov 02 '15 at 16:04
Oh, they looked somewhat different to me, I just thought that they were the same, but I need the letter in the title of the paper, i.e. the LATIN SMALL LETTER OPEN E. How would I represent that using the latex encoding? And also it should be text, I guess, although I can't really tell from looking at it... — user35915, Nov 02 '15 at 16:06
I have never seen that character used anywhere, ever:-) It is not in any of the standard tex encodings as far as I know, so if you are using pdftex I guess you will have to fake it with $\varepsilon$ I'll add an answer showing how to get that output from the utf8 input — David Carlisle, Nov 02 '15 at 16:10
Wow really :-)? Well the paper is rather old, maybe they used it back then...ok thanks! — user35915, Nov 02 '15 at 16:11
While that paper you cite is using a latin open e, I think that is simply a poor html encoding in that site, wikipedia suggests that the correct name is an epsilon https://en.wikipedia.org/wiki/Epsilon_Aurigae — David Carlisle, Nov 02 '15 at 16:20
Yes, you're probably right. Just in case I encounter a similar situation in the future: is there a webpage or something where I can find out, what exact letter or symbol I'm looking at and how it is encoded in unicode? I will try your solution in the evening and the accept your answer, if I get it to work... — user35915, Nov 02 '15 at 16:31
The canonical one is this http://r12a.github.io/apps/conversion/ but actually I used this https://w3c.github.io/xml-entities/unicode-names.html (as it's my file:-) — David Carlisle, Nov 02 '15 at 16:35

score 6 · Accepted Answer · answered Nov 02 '15 at 16:16

Using UTF-8 text input and rather basic math approximations we get:

\documentclass{article}

\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\DeclareUnicodeCharacter{025B}{\ensuremath{\varepsilon}}
\DeclareUnicodeCharacter{03F5}{\ensuremath{\epsilon}}
\DeclareUnicodeCharacter{03B5}{\ensuremath{\varepsilon}}

\begin{document}

latin open e U+025b [ɛ]  

lunate epsilon U+03f5 [ϵ] 

epsilon U+03b5 [ε]

\end{document}

egreg · Answer 2 · 2015-11-02T16:55:14.053

Use the right packages, in this case textalpha; note that ε is U+03B5 GREEK SMALL LETTER EPSILON. Since we're dealing with the name of a star, the Greek letter is to be used. I also fixed the BibTeX entry for the paper, which had a few errors.

\begin{filecontents*}{\jobname.bib}
@ARTICLE{1937ApJ....86..570K,
   author = {Kuiper, G. P. and Struve, O. and Str{\"o}mgren, B.},
    title = {The Interpretation of ε {Aurigae}},
  journal = {Astrophysical Journal},
     year = 1937,
    month = dec,
   volume = 86,
    pages = {570},
      doi = {10.1086/143888},
   adsurl = {http://adsabs.harvard.edu/abs/1937ApJ....86..570K},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
\end{filecontents*}

\documentclass{article}
\usepackage[T1]{fontenc} % optional
\usepackage[utf8]{inputenc}

\usepackage{textalpha}

\begin{document}

\cite{1937ApJ....86..570K}

\bibliographystyle{plain}

\bibliography{\jobname}

\end{document}

What input encoding do I have to choose if I have an 'ɛ' in a reference title?

2 Answers2