# Frege's Notation for Part III of the Begriffsschrift

There are a couple packages I know of for helping one to lay out Frege's notation, with a focus on that in Basic Laws of Arithmetic (Grundgesetze der Arithmetik): begriff, fge, grundgesetze. However, it seems that none of these handle the notation he developed for Part III of Begriffsschrift (& then abandoned for Basic Laws). I'm trying to figure out what the best way to layout something like the below might be:

Any recommendations?

Once I typeset the Begriffsschrift and I had to solve the problem that you describe too. I placed my solution in a package called GFnotation (OK, it is not the best name) and you can find it on CTAN. It does not only typeset the symbol called property F is hereditary in the f-sequence'' but it can be used to handle all of Frege's notation in the Begriffsschrift.

Have a look at my article in TUGboat: Typesetting the Begriffsschrift' by Gottlob Frege in plain TeX.''

A simple solution with blkarray:

\documentclass[a4paper,12pt]{report}
\usepackage[utf8]{inputenc}
\usepackage{fourier}
\usepackage[x11names]{xcolor}
\usepackage{empheq}
\usepackage{blkarray}

\begin{document}
$\makeatletter \BA@colsep=4pt \makeatother\begin{blockarray}{c(l} \alpha & F(\alpha )\\ \rule[-1.5ex]{0.8pt}{3.5ex}\\ \delta & f(\delta, \alpha ) \end{blockarray}$

\end{document}


Stack it!!

\documentclass{article}
\usepackage[usestackEOL]{stackengine}
\stackMath
\begin{document}
$\Centerstack{\alpha \\ \vert\\ \delta} \biggl( \Centerstack[l]{F(\alpha) \\ \\ f(\delta,\alpha)}$
\end{document}


• Amazing!!! So natural. – Sigur Apr 22 '17 at 12:44

It ain't pretty, but perhaps this is a start of a solution?

\documentclass{article}
\begin{document}
\vcenter{\offinterlineskip\halign{\hfil\phantom{(}#\hfil\cr\alpha\cr|\cr\delta\cr}} \!\bigg( \vcenter{\offinterlineskip\halign{#\hfil\cr F(\alpha)\cr\phantom{|}\cr f(\delta,\alpha)\cr}}
\end{document}


You might perhaps want to make this into a macro...

Some simple solution, but with problem in alignment. Maybe could be combined with others to improve it.

\documentclass[11pt,a4paper]{report}
\usepackage{amsmath,amssymb,amsfonts}
\DeclareMathOperator*{\foo}{\Big\vert}
\newcommand{\frege}[2]{\foo_{#2}^{#1} \Biggr(_{f(#1,#2)}^{F(#1)}}
\begin{document}
$\foo_{\delta}^{\alpha} \Biggr(_{f(\alpha,\delta)}^{F(\alpha)}$

$\frege{\alpha}{\delta}$
\end{document}
`