Cannot generate hyphen

Question

I am new to TEX and am using scribtex as an online latex editor. My problem is that when I put hyphen in my text it sometimes appears and sometimes doesn't appear. What can be the reason for this and how do I fix this?

The code for example I am putting in is:

  \documentclass[12pt,oneside]{amsart}
  \usepackage{amssymb}
  \theoremstyle{plain}
  \newtheorem{theorem}{Theorem}[section]
  \newtheorem{lemma}[theorem]{Lemma}
  \newtheorem{corollary}[theorem]{Corollary}
  \theoremstyle{definition}
  \newtheorem{definition}[theorem]{Definition}
  \theoremstyle{remark}
  \newtheorem{remark}[theorem]{Remark}
  \newcommand{\R}{{\mathbb R}}
  \newcommand{\nil}{\varnothing}
  \begin{document}
  Reissener–Nordstrom 
  Reissener – Nordstrom 
  \end{document}

​ The output I get is "ReissenerNordstrom Reissener Nordstrom" whereas I expect "Reissener-Nordstrom Reissener-Nordstrom".

Thanks

Answer 1

what you call a hyphen is the unicode character for a n-dash. You can see it with

\documentclass[12pt,oneside]{amsart}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{amssymb}
[...]

I changed the first one to a hyphen to make the difference visible:

Answer 2

Hyphens are used for compound words like: son-in-law. For number ranges use two dashes: 15--24. Punctuation in sentences uses three dashes --- such as this. However, if you are in math mode then things are different as a dash is a minus sign. So, you need to use either \hbox, or \mbox, or \text (if you have amsmath pacakge loaded).

I just tied pasting the code below at http://scribtex.com, and the output PDF that I got seems to work fine.

\documentclass{article}
\usepackage{amsmath}
\begin{document}

Compound words like: daughter-in-law.\par
Number ranges: 15--24.\par
Punctuation in sentences---such as this.

\bigskip
However, in math mode, a dash gets treated as a minus sign:
$15-25$, $15--24$ 

So use \textbackslash mbox (or \textbackslash hbox) to get back to text mode:
$a \mbox{-} b$  $15 \mbox{--} 24$

\bigskip
or with `amsmath` you can also use `\textbackslash text`:
$a \text{-} b$  

$14 \text{--} 24$
\end{document}