Is there a `let` quantifier in LATEX?

Question

Is there a let quantifier in LATEX? (It looks like \exists, but without a middle stick)

Answer 1

Here is a (humble) possibility using tikz. It won't resist scaling though

\documentclass{standalone}
\usepackage{tikz,amstext}
\newlength{\tempheight}
\newcommand{\Let}[0]{%
\mathbin{\text{\settoheight{\tempheight}{\mathstrut}\raisebox{0.5\pgflinewidth}{%
\tikz[baseline,line cap=round,line join=round] \draw (0,0) --++ (0.4em,0) --++ (0,1.5ex) --++ (-0.4em,0);%
}}}}
\begin{document}
$\Let\exists\alpha\beta\gamma$
\end{document} 

Answer 2

I used that quantor during my stury in Saint-Petersburg State University, and I wonder, if that sign being used in other places. Searched for it several times, found an old FIDO mail with DIY-version:

\documentclass{standalone}
\def\letus{%
    \mathord{\setbox0=\hbox{$\exists$}%
             \hbox{\kern 0.125\wd0%
                   \vbox to \ht0{%
                      \hrule width 0.75\wd0%
                      \vfill%
                      \hrule width 0.75\wd0}%
                   \vrule height \ht0%
                   \kern 0.125\wd0}%
           }%
}
\begin{document}
$\letus$
\end{document}

Answer 3

The closest symbol in Unicode is ⊐ (U+2290), the Square Original Of. Since this is a relational operator, you would want to change its spacing to

\newcommand\letsymbol{\mathord{\sqsupset}}

This works with numerous packages, including unicode-math, amssymb and latexsym.