# How to write this symbol (vee with double line left)

I want to write this symbol:

but cannot find anywhere how to do it. Detexify did'nt find it.

Edit: Thank you very much for your solutions but i forgot to write that i need this symbol in the size (and with the same behaviour) like "bigvee" I dont understand anything of the commands your solutions used, so i cannot change it myself, sorry.

• Does $$\mathbb{V}$$ with amssymb package loaded works for you? – koleygr Aug 25 at 12:17
• What is the mraning of this symbol? – barbara beeton Aug 25 at 13:40
• But is it a mathematical symbol that you created? – Sebastiano Aug 25 at 14:39
• @koleygr i thought about this too but it's not quiet the same – T_01 Aug 26 at 12:11

Here's my proposal:

\documentclass{article}
\usepackage{amsmath}
\usepackage{pict2e,xfp}

\makeatletter
\newcommand{\dvee}{\mathbin{\mathpalette\d@vee\relax}}
\newcommand{\d@vee}[2]{%
\begingroup
\sbox\z@{$\m@th#1\vee$}%
\setlength{\unitlength}{\ht\z@}%
\kern0.1\wd\z@
\begin{picture}(\fpeval{0.4\wd0/\unitlength},1)
\roundcap\d@vee@thickness{#1}
\Line(0,1.03)(\fpeval{0.4\wd0/\unitlength},0)
\end{picture}%
\kern-0.3\wd\z@\box\z@
\endgroup
}
\newcommand{\d@vee@thickness}[1]{% see https://tex.stackexchange.com/a/477200/
\linethickness{%
1\fontdimen8
\ifx#1\displaystyle\textfont\else
\ifx#1\textstyle\textfont\else
\ifx#1\scriptstyle\scriptfont\else
\scriptscriptfont\fi\fi\fi 3
}%
}
\makeatother

\begin{document}

$a \vee a \dvee a$\quad $\scriptstyle a \vee a \dvee a$

\fboxsep=0pt\fboxrule=0.1pt

\fbox{$\vee$}

\fbox{$\dvee$}

\end{document}

For the analog to \bigvee:

\documentclass{article}
\usepackage{amsmath}
\usepackage{pict2e,xfp}

\makeatletter
\newcommand{\bigdvee}{\mathop{\mathpalette\bigd@vee\relax}}
\newcommand{\bigd@vee}[2]{%
\ifx#1\displaystyle
\displaystylebigd@vee
\else
\begingroup
\sbox\z@{$\m@th#1\bigvee$}%
\setlength{\unitlength}{\dimexpr\ht\z@+\dp\z@}%
\kern0.07\wd\z@
\raisebox{-\dp\z@}{%
\begin{picture}(\fpeval{0.45\wd0/\unitlength},1)
\roundcap\bigd@vee@thickness{#1}%
\Line(0.03,0.97)(\fpeval{0.45\wd0/\unitlength},0.03)
\end{picture}%
}%
\kern-0.3\wd\z@\box\z@
\endgroup
\fi
}
\newcommand{\bigd@vee@thickness}[1]{% see https://tex.stackexchange.com/a/477200/
\linethickness{%
1.75\fontdimen8
\ifx#1\textstyle\textfont\else
\ifx#1\scriptstyle\scriptfont\else
\scriptscriptfont\fi\fi 3
}%
}
\def\displaystylebigd@vee{%
\begingroup
\sbox\z@{$\m@th\displaystyle\bigvee$}%
\setlength{\unitlength}{0.825\dimexpr\ht\z@+\dp\z@}%
\kern0.07\wd\z@
\raisebox{-0.75\dp\z@}{%
\begin{picture}(\fpeval{0.45\wd0/\unitlength},1)
\roundcap\linethickness{2\fontdimen8\textfont3}
\Line(0,1)(\fpeval{0.45\wd0/\unitlength},0)
\end{picture}%
}%
\kern-0.3\wd\z@\box\z@
\endgroup
}
\makeatother

\begin{document}

$\displaystyle \bigvee a + \bigdvee a$\quad
$\textstyle \bigvee a + \bigdvee a$\quad
$\scriptstyle a \bigvee a \bigdvee a$

\fboxsep=0pt\fboxrule=0.1pt

\fbox{$\bigvee$}

\fbox{$\bigdvee$}

\fbox{$\displaystyle\bigvee$}\fbox{$\displaystyle\bigdvee$}

\end{document}

• see my edit please – T_01 Aug 26 at 12:15
• @T1 See the edit. – egreg Aug 26 at 19:55

I propose two solutions, based on the versions of leqslantin amssymb and mathabx (without loading the latter fonts):

\documentclass{article}
\usepackage{amssymb}
\usepackage{graphicx}
\newcommand{\dbvee}{\mathbin{\rotatebox[origin=c]{-90}{$\geqslant$}}}

\DeclareFontFamily{U}{matha}{\hyphenchar\font45}
\DeclareFontShape{U}{matha}{m}{n}{ <-6> matha5 <6-7> matha6 <7-8>
matha7 <8-9> matha8 <9-10> matha9 <10-12> matha10 <12-> matha12 }{}
\DeclareSymbolFont{matha}{U}{matha}{m}{n}

\DeclareMathSymbol{\abxgeqslant}{\mathord}{matha}{"A5}
\newcommand{\abxdbvee}{\mathbin{\rotatebox[origin=c]{-90}{$\abxgeqslant$}}}

\begin{document}

$A\dbvee B \qquad A\abxdbvee B$%

\end{document}

Edit:

To have the same symbol with \bigvee, you can add this to you preamble:

\usepackage{stackengine, mathtools}
\newcommand{\bigeqvee}{\stackMath\mathop{\stackinset{l}{-2pt}{c}{-0.5pt}{\scalebox{1.35}{$\setminus$}}{\displaystyle\bigvee}}}

and type in the body of your document

$A = \bigeqvee_{\mathclap{i\in I}} A_i$%

(of course this works only for display style. For a more general use, one would have to use \mathpalette, in order to adapt the code to textstyle, script style ans=d scriptscriptcstyle –) but will you need them?

• see my edit please – T_01 Aug 26 at 12:15
• I've added a solution for this case. – Bernard Aug 26 at 19:38