# Peirce's notation for logical connectives

How to write the Peirce notation for logical connective?

• Are you aware of this post? – marmot Jan 25 '18 at 19:08
• I already tried, but there are only two or three results. Not the complete list. – G al Cubo Jan 25 '18 at 19:12
• i think that not all of these are in any font that i know of. i'm pretty sure they didn't all make it into unicode. can you provide a reference to a published source where they are defined and used? with that information, i can submit the request to unicode to add whatever is missing. – barbara beeton Jan 25 '18 at 19:15
• @barbarabeeton ^^ Edited question. By the way, if somebody needs a new symbol, how do they get it? Short of drawing, isn't there a chicken-and-egg problem here? Not in unicode -> not in fonts -> can't typeset it -> can't use it. Can't use it -> not a candidate for unicode. Hence, we have to make do with only the symbols invented prior to unicode? – cfr Jan 27 '18 at 3:52
• @barbarabeeton [Not a serious question, obviously.] – cfr Jan 27 '18 at 3:58

Maybe using tikz and writing a short macro:

\documentclass{article}
\usepackage{tikz}

\newcommand{\piercebox}[1]{%
\def\parr{{#1}}%
\tikz[line cap=round,scale=.25]{
\pgfmathparse{\parr[0]}
\draw[black!0] (0,0) -- (0,1) -- (1,1) -- (1,0);
\ifnum\pgfmathresult=1
\draw (0,0) -- (0,1);
\fi
\pgfmathparse{\parr[1]}
\ifnum\pgfmathresult=1
\draw (1,0) -- (1,1);
\fi
\pgfmathparse{\parr[2]}
\ifnum\pgfmathresult=1
\draw (0,1) -- (1,1);
\fi
\pgfmathparse{\parr[3]}
\ifnum\pgfmathresult=1
\draw (0,0) -- (1,0);
\fi
\pgfmathparse{\parr[4]}
\ifnum\pgfmathresult=1
\draw (0,0) -- (1,1);
\fi
\pgfmathparse{\parr[5]}
\ifnum\pgfmathresult=1
\draw (1,0) -- (0,1);
\fi
}%
}

\begin{document}

\piercebox{1,0,0,0,0,0}
\piercebox{0,1,0,0,0,0}
\piercebox{0,0,1,0,0,0}
\piercebox{0,0,0,1,0,0}
\piercebox{0,0,0,0,1,0}
\piercebox{0,0,0,0,0,1}

\bigskip

\piercebox{1,1,1,1,1,1}

\piercebox{1,1,1,0,1,1}
\piercebox{1,0,1,1,1,1}
\piercebox{0,1,1,1,1,1}
\piercebox{1,1,0,1,1,1}

\piercebox{0,1,0,1,1,1}
\piercebox{1,0,0,1,1,1}
\piercebox{1,1,0,0,1,1}
\piercebox{0,0,1,1,1,1}
\piercebox{0,1,1,0,1,1}
\piercebox{1,0,1,0,1,1}

\piercebox{0,0,1,0,1,1}
\piercebox{1,0,0,0,1,1}
\piercebox{0,1,0,0,1,1}
\piercebox{0,0,0,1,1,1}

\piercebox{0,0,0,0,1,1}

\end{document}

Which yields:

picture mode to the rescue:

\documentclass{article}

\newcommand\zz[6]{%
\begin{picture}(10,10)
\ifnum#1=1 \put(0,0){\line(1,0){10}}\fi
\ifnum#2=1 \put(10,0){\line(0,1){10}}\fi
\ifnum#3=1 \put(0,10){\line(1,0){10}}\fi
\ifnum#4=1 \put(0,0){\line(0,1){10}}\fi
\ifnum#5=1 \put(0,0){\line(1,1){10}}\fi
\ifnum#6=1 \put(0,10){\line(1,-1){10}}\fi
\end{picture}}

\begin{document}

\zz111111 + \zz010101 + \zz000011 + \zz111110

\end{document}
• Thanks! I knew there was a simpler approach than using tikz but it just was the first thing that came to my mind … – Jasper Habicht Jan 25 '18 at 19:53
• Yes. It is very good construction (and it is very beautiful). But for now I prefer the construction with Tikz because in fact I am working some diagrams with Tikz. – G al Cubo Jan 25 '18 at 20:08
• @JasperHabicht when tikz is the first thing that comes to your mind, you should start to worry about your state of mind:-) – David Carlisle Jan 25 '18 at 20:49
• @GalCubo And when picture mode is the first thing that comes to your mind, you should start to worry that your mind may be David Carlisle's. – cfr Jan 27 '18 at 3:47

A variation on the picture theme. This provides symbols that adapt to the current font size. Smaller symbols are needed, for instance, in table 5 of the article.

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

\makeatletter
\DeclareRobustCommand{\peirceconn}[1]{%
% #1 = four bit binary number: top, left, right, bottom
% 0 = false, 1 = true
\mathrel{\mathpalette\peirce@conn{#1}}%
}
\newcommand{\peirce@conn}[2]{%
\peirce@@conn#1#2....\@nil
}
\def\peirce@@conn#1#2#3#4#5#6\@nil{
\settoheight{\unitlength}{$#1F$}
\begin{picture}(1.2,1)
\roundcap
\peirce@linethickness{#1}
\ifnum#2=0 % top is false
\Line(0.1,1)(1.1,1)
\fi
\ifnum#3=0 % left is false
\Line(0.1,0)(0.1,1)
\fi
\ifnum#4=0 % right is false
\Line(1.1,0)(1.1,1)
\fi
\ifnum#5=0 % bottom is false
\Line(0.1,0)(1.1,0)
\fi
\Line(0.1,0)(1.1,1)
\Line(0.1,1)(1.1,0)
\end{picture}
}
\newcommand{\peirce@linethickness}[1]{%
\linethickness{%
\fontdimen8
\ifx#1\displaystyle\textfont\else
\ifx#1\textstyle\textfont\else
\ifx#1\scriptstyle\scriptfont\else
\scriptscriptfont\fi\fi\fi 3
}%
}
\makeatother

\begin{document}

$\peirceconn{0000}$
$\peirceconn{0001}$
$\peirceconn{0010}$
$\peirceconn{0100}$
$\peirceconn{1000}$
$\peirceconn{1100}$
$\peirceconn{1010}$
$\peirceconn{1001}$
$\peirceconn{0110}$
$\peirceconn{0101}$
$\peirceconn{0011}$
$\peirceconn{0111}$
$\peirceconn{1011}$
$\peirceconn{1101}$
$\peirceconn{1110}$
$\peirceconn{1111}$

$x\peirceconn{1111}y\frac{x\peirceconn{1110}y}{x\peirceconn{0001}y}$

\footnotesize

$x\peirceconn{0101}y$

\Large

$x\peirceconn{1010}y$

\end{document}

Compare with the original table

• Gracias! Muy bonito! – G al Cubo Jan 27 '18 at 13:57
• see cfr's comment under my answer – David Carlisle Jan 27 '18 at 15:13
• @DavidCarlisle But I'm using pict2e. ;-) – egreg Jan 27 '18 at 15:19