[Tex/LaTex] Empty set symbols confused

amssymb

I am trying to typeset the symbol for empty set and using the answer of that question I chose \varnothing but when I used it I got the symbol that is described to be \emptyset and vice versa. Also when I use the amssymb package I get these errors:

Command `\eth' already defined.

Command `\digamma' already 

Command `\backepsilon' already

If I don't useamssymb it still happens the same regarding those 2 symbols. What is happening? How can I get the right symbol? (Meaning the \varnothing)

\documentclass[12pt]{article}

\usepackage{fontspec}

\setmainfont
[
  Ligatures=TeX,
  Extension=.otf,
  UprightFont=*,
  BoldFont=*Bold,
  ItalicFont=*It,
  BoldItalicFont=*BoldIt,
  Mapping=tex-text
]{GFSArtemisia}

\setsansfont[Mapping=tex-text]{GFSArtemisia.otf}

\usepackage[english,greek]{babel}

\usepackage[fleqn]{amsmath}

\usepackage{unicode-math}

\begin{document}

This is the problem:

\vspace{1cm}

$\varnothing \quad \emptyset$

\end{document}

Best Answer

There are not two distinct Unicode points for the empty set and its variant symbol (they are just different forms of the same symbol). Find a font that has the circle form and use it.

\documentclass[12pt]{article}

\usepackage[fleqn]{amsmath}
\usepackage{unicode-math}
\usepackage[english,greek]{babel}

\setmainfont[
  Ligatures=TeX,
  Extension=.otf,
  UprightFont=*,
  BoldFont=*Bold,
  ItalicFont=*It,
  BoldItalicFont=*BoldIt,
]{GFSArtemisia}

%\setsansfontMapping=tex-text]{GFSArtemisia.otf} %%% it's not sans serif!

\setmathfont{Latin Modern Math}
\setmathfont[range=\varnothing]{Asana Math}
\setmathfont[range=\int]{Latin Modern Math}

\begin{document}

This is the problem: $\varnothing\subseteq A\times B$

\end{document}

enter image description here

By the way, Latin Modern Math together with GFS Artemisia doesn't seem too nice a combination. If your document is math intensive, Artemisia for the Latin characters is not recommendable, in my opinion, because there's no matching math font.

Loading Latin Modern Math explicitly is necessary if another math font is chosen for some range of characters (it's a bug of fontspec, I'd say).

Note that, depending on the host system (say ShareLaTeX or WriteLaTeX) or your own system, the font may have to be loaded by file name and not by font name; in this case, the math fonts should be loaded with

\setmathfont{latinmodern-math.otf}
\setmathfont[range=\varnothing]{Asana-Math.otf}
\setmathfont[range=\int]{latinmodern-math.otf}
Related Question