In order to distinguish between object language and meta language I want a rather visible difference between the signs mentioned in the title as used in the object language and as used in the formal meta language. How do I best achieve this?
I am not satisfied with the minor difference between $\boldsymbol{{}()\vee} and ${}()\vee$.
Perhaps there are some related symbols in http://linorg.usp.br/CTAN/info/symbols/comprehensive/symbols-a4.pdf that I could use?
I introduce \fat that emboldens the argument with a multi-offset-overlay. While it can be invoked in text mode or math mode, its argument is processed in math mode (unless delimited by $ which will process it in text mode). Importantly, the current math style is preserved. For things like \vee, it is easier to define \fvee in terms of \fat and \vee.
\documentclass{article}
\usepackage{scalerel}
\newcommand\fat[1]{\ThisStyle{\ooalign{%
\kern.46pt$\SavedStyle#1$\cr\kern.33pt$\SavedStyle#1$\cr%
\kern.2pt$\SavedStyle#1$\cr$\SavedStyle#1$}}}
\def\fvee{\mathbin{\fat{\vee}}}
\begin{document}
$\{(xyz\vee abc)\} \scriptscriptstyle
\{(xyz\vee abc)\}$
$\fat\{\fat(xyz\fvee abc\fat)\fat\} \scriptscriptstyle
\fat\{\fat(xyz\fvee abc\fat)\fat\}$
\fat aa\fat{$a$}
\end{document}
If you really wanted to enhance the effect, you could add a small horizontal stretch to the result (in this case 20%):
\documentclass{article}
\usepackage{scalerel}
\newcommand\fat[1]{\ThisStyle{\hstretch{1.2}{\ooalign{%
\kern.46pt$\SavedStyle#1$\cr\kern.33pt$\SavedStyle#1$\cr%
\kern.2pt$\SavedStyle#1$\cr$\SavedStyle#1$}}}}
\def\fvee{\mathbin{\fat{\vee}}}
\begin{document}
$\{(xyz\vee abc)\} \scriptscriptstyle
\{(xyz\vee abc)\}$
$\fat\{\fat(xyz\fvee abc\fat)\fat\} \scriptscriptstyle
\fat\{\fat(xyz\fvee abc\fat)\fat\}$
\fat aa\fat{$a$}
\end{document}
A solution based on package pdfrender to additionally stroke the symbols with a line width.
\documentclass{article}
\usepackage{amsmath}% for environment "gather*"
\usepackage{pdfrender}
\newcommand*{\fatten}[1][.4pt]{%
\textpdfrender{
TextRenderingMode=FillStroke,
LineWidth={\dimexpr(#1)\relax},
}%
}
\begin{document}
\begin{gather*}
(a \vee b) = \{a \vee b\}
\\
\fatten{(} a \fatten{\vee} b \fatten{)} =
\fatten{\{} a \fatten{\vee} b \fatten{\}}
\\
\fatten[1pt]{(} a \fatten[1pt]{\vee} b \fatten[1pt]{)} =
\fatten[1pt]{\{} a \fatten[1pt]{\vee} b \fatten[1pt]{\}}
\end{gather*}
\end{document}
Caution:
The increased stroke width does not contribute to the width of the symbol. A macro can compensate this:
\newcommand*{\fatvee}[1][1pt]{%
\mathbin{%
\kern.5\dimexpr(#1)\relax
\fatten[{#1}]{\vee}%
\kern.5\dimexpr(#1)\relax
}%
}
Full example with width compensation:
\documentclass{article}
\usepackage{amsmath}% for environment "gather*"
\usepackage{pdfrender}
\newcommand*{\fatten}[1][.4pt]{%
\textpdfrender{
TextRenderingMode=FillStroke,
LineWidth={\dimexpr(#1)\relax},
}%
}
\newcommand*{\fatdef}[4][1pt]{%
% #1: optional stroke width
% #2: new macro for fattened symbol
% #3: math atom type (\mathbin, \mathrel, ...)
% #4: symbol
\newcommand*{#2}{%
#3{%
\kern.5\dimexpr(#1)\relax
\fatten[{#1}]{#4}%
\kern.5\dimexpr(#1)\relax
}%
}%
}
\fatdef\fatvee\mathbin\vee
\fatdef\fatlparen\mathopen(
\fatdef\fatrparen\mathclose)
\fatdef\fatlbrace\mathopen\{
\fatdef\fatrbrace\mathclose\}
\begin{document}
\begin{gather*}
(a \vee b) = \{a \vee b\}
\\
\fatlparen a \fatvee b \fatrparen =
\fatlbrace a \fatvee b \fatrbrace
\end{gather*}
\end{document}
\left and \right can be supported by a macro that resets the rendering mode for the formula inside the fences:
\documentclass{article}
\usepackage{amsmath}% for environment "gather*"
\usepackage{pdfrender}
\newcommand*{\fatten}[1][.4pt]{%
\textpdfrender{
TextRenderingMode=FillStroke,
LineWidth={\dimexpr(#1)\relax},
}%
}
\newcommand*{\fatdef}[4][1pt]{%
% #1: optional stroke width
% #2: new macro for fattened symbol
% #3: math atom type (\mathbin, \mathrel, ...)
% #4: symbol
\newcommand*{#2}{%
#3{%
\kern.5\dimexpr(#1)\relax
\fatten[{#1}]{#4}%
\kern.5\dimexpr(#1)\relax
}%
}%
}
\newcommand*{\fatleftrightdef}[4][1pt]{%
% #1: optional stroke width
% #2: new macro name
% #3: left fence
% #4: right fence
\newcommand*{#2}[1]{%
\kern.5\dimexpr(#1)\relax
\fatten[{#1}]{%
\left#3%
\kern.5\dimexpr(#1)\relax
\textpdfrender{TextRenderingMode=Fill}{##1}%
\kern.5\dimexpr(#1)\relax
\right#4%
}%
\kern.5\dimexpr(#1)\relax
}%
}
\fatdef\fatvee\mathbin\vee
\fatleftrightdef\fatleftrightparens()
\fatleftrightdef\fatleftrightbraces\{\}
\begin{document}
\begin{gather*}
\left( \frac{a}{a} \vee \frac{b}{b} \right) =
\left\{ \frac{a}{a} \vee \frac{b}{b} \right\}
\\
\fatleftrightparens{ \frac{a}{a} \fatvee \frac{b}{b} } =
\fatleftrightbraces{ \frac{a}{a} \fatvee \frac{b}{b} }
\end{gather*}
\end{document}
\mathtt{}? – Sigur Feb 18 '15 at 18:14\mathbf{}or\boldsymbol{}– MaxNoe Feb 18 '15 at 18:22\mathbf{\vee}and\vee, same for the brackets and parentheses. – MaxNoe Feb 18 '15 at 18:35I am very satisfied with your answer, and use the approach you kindly offered.
– Frode Alfson Bjørdal Feb 19 '15 at 20:46