\vDash and \models but with three horizontal lines

Question

I'm looking for way to draw the \vDash or the \models operator but with three horizontal lines instead of just two. Is there an easy way to do this?

It should look something like this:

Thanks for any help!!

Answer 1

You can mimick the definition of \models, but with a slight change so the subscript is a bit lower.

\documentclass{article}
\usepackage{amsmath}
\newcommand{\mmmodels}{\mathrel{|\mkern-3.5mu{\equiv}}}
\begin{document}
[
\mmmodels_K
]
\end{document}

Answer 2

A little extension on egreg's answer that scales to the math style being used via \mathchoice:

\documentclass{article}
\newcommand{\mmmodels}{%
  \mathrel{
    {|}
    \mathchoice{\mkern -3.5mu}{\mkern -3.5mu}{\mkern -4mu}{\mkern -4.5mu}
    {\equiv}
  }
}
\begin{document}
$a \mmmodels b_{a \mmmodels b_{a \mmmodels b}}$
\end{document}

Answer 3

U+2AE2 VERTICAL BAR TRIPLE RIGHT TURNSTILE ⫢ is \vDdash in unicode-math for lualatex and xelatex or compatible packages such as stix2 for pdflatex

\documentclass{article}
\usepackage{stix2}
\begin{document}
[
A \vDdash B
]
\end{document}

Answer 4

The turnstile package is designed for typesetting various configurations of turnstiles with or without text above and below the bar.

For your case, you want a single vertical bar on the left followed by a triple horizontal bar, and no text, so the command is \sttstile{}{}:

\documentclass{article}
\usepackage{turnstile}
\begin{document}
[
\sttstile{}{} K
]
\end{document}