Triple turnstile symbol

Question

I want a triple-bar turnstile symbol to go alongside the single-bar \vdash and the double-bar \vDash – a symbol the same size and weight as the Computer Modern turnstiles:

(The Comprehensive LaTeX Symbol List tells me there is is a stix version, but it doesn't really match the CM symbols.)

I can cook up something that almost works with | and \equiv and \raisebox and \tiny etc.

But I'm just wondering if someone has a nicer solution out there!

Answer 1

You could just superimpose the two present symbols (\vDdashA). If you want more control over the spacing, \vDdashB is another possibility (I don't know if there are better possibilities to get the dash than using a \clipbox).

\documentclass{article}

\usepackage{amssymb}
\usepackage{trimclip} % for \vDdashB

\newcommand*\vDdashA{%
  \mathrel{%
    \ooalign{$\vdash$\cr$\vDash$}%
  }%
}
\def\@clipped@vdash{%
  \raise .6ex\hbox{\clipbox{0pt .6ex 0pt .6ex}{$\vdash$}}%
}
\newcommand*\vDdashB{%
  \mathrel{%
    \ooalign{%
      $\vdash$\cr
      \raise  .3ex\hbox{\@clipped@vdash}\cr
      \raise -.3ex\hbox{\@clipped@vdash}%
    }%
  }%
}

\begin{document}

\(a \vdash b\)

\(a \vDdashA b\)

\(a \vDdashB b\)

\end{document}