How can I produce this expression in latex: ⌜A⌝?

Question

I want to introduce a unique operator in my document. I basically want it to look like this: ⌜A⌝, where A is just an arbitrary statement. So '⌜⌝' is the operator.

How can I produce the ⌜ and ⌝ symbols here? The closest I've gotten so far are the \lceil and \rceil commands, but they're not really satisfying since they're way too large. It just looks like this: ⌈A⌉. How could I create a new command for the type of operator I'm looking for?

I'm using amsmath and LuaLaTeX on overleaf in case that's relevant here.

Answer 1

If the versions of the \ulcorner and \urcorner symbols provided by the amssymb package are a bit too large for your taste, you could try those provided by the unicode-math package.

Depending on the letter that forms the argument of \upcorner, some fine-tuning may be needed. E.g., for the letter T, the output of \upcorner{\,T} looks better than that of \upcorner{T}.

% !TEX TS-program = lualatex
\documentclass{article}
\usepackage{mathtools}    % for \DeclarePairedDelimiter macro
\usepackage{unicode-math} % for \ulcorner and \urcorner macros
\newcommand\upcorner[1]{\ulcorner\!#1\urcorner}
\DeclarePairedDelimiter\ceil\lceil\rceil % just for comparison
\begin{document}
$\upcorner{A}\ \upcorner{B}\ \upcorner{C}\ \dots\ 
 \upcorner{X}\ \upcorner{Y}\ \upcorner{Z}$
$\scriptstyle\upcorner{A}\ \upcorner{B}\ \upcorner{C}\ \dots\ 
 \upcorner{X}\ \upcorner{Y}\ \upcorner{Z}$
$\scriptscriptstyle\upcorner{A}\ \upcorner{B}\ \upcorner{C}\ \dots\ 
 \upcorner{X}\ \upcorner{Y}\ \upcorner{Z}$
\medskip
$\upcorner{A}$ vs.\ $\ceil{A}$

\end{document}

Answer 2

You could try \urcorner and \ulcorner from amssymb:

\documentclass{article}
\usepackage{amssymb}
\begin{document}
[
 \ulcorner T \urcorner
]
\end{document}

Answer 3

You can search on "C:\texlive\2023\texmf-dist\doc\latex\comprehensive\symbols-a4.pdf" by \ulcorner.

\documentclass{article}
\usepackage{amsmath}
\usepackage{amssymb}
% \usepackage{MnSymbol}
% \usepackage{fdsymbol}
% \usepackage{stix}
% \usepackage{mathabx}
\begin{document}
$\ulcorner A\urcorner$ amssymb
% $\ulcorner A\urcorner$ MnSymbol
% $\ulcorner A\urcorner$ fdsymbol
% $\ulcorner A\urcorner$ stix
% $\ulcorner A\urcorner$ mathabx
\end{document}

Answer 4

A variant of https://tex.stackexchange.com/a/674742/4427

\documentclass{article}
\usepackage{amsmath}
\usepackage{tikz}
\makeatletter
\NewDocumentCommand{\godel}{m}{{\mathpalette\godel@{#1}}}
\newcommand{\godel@}[2]{%
  \mspace{1\medmuskip}%
  \vphantom{#2}%
  \begin{tikzpicture}[baseline=(M.south)]
    \nodeinner ysep=0pt,inner xsep=3pt{\smash[b]{$\m@th#1\mathstrut#2$}};
    \draw([xshift=-1mm]M.north east)--(M.north east)--++(0,-.1);
    \draw([xshift=1mm]M.north west)--(M.north west)--++(0,-.1);
  \end{tikzpicture}%
  \mspace{1\medmuskip}%
}
\makeatother
\begin{document}
$\godel{A}$
$\godel{a+b}$
\medskip
$\displaystyle\godel{\sum_{n\ge0}a_n}$
\end{document}