LaTeX macros for Fitch style natural deduction
Fitchstyle natural deduction is a system for writing proofs in
propositional logic and predicate logic. We use it in our logic
courses at the University of Ottawa. This is a set of easytouse
LaTeX macros that I wrote for making handouts for my classes.
With these macros, one can typeset natural deduction proofs in
Fitch style, as in the following example:


\begin{nd}
\hypo {1} {\forall y \neg P(y)}
\open
\hypo {2} {\exists x P(x)}
\open[u]
\hypo {3} {P(u)}
\have {4} {\forall y \neg P(y)} \r{1}
\have {5} {\neg P(u)} \Ae{4}
\have {6} {\bot} \ne{3,5}
\close
\have {6a}{\bot} \Ee{2,36}
\close
\have {7} {\neg \exists x P(x)} \ni{26a}
\end{nd}

The output is shown on the left, and the corresponding LaTeX code on
the right.
News
Version 0.6, Sep 5, 2023. The fitch package is now maintained
by Richard Zach, University of Calgary. It's available
from GitHub
and CTAN.
Version 0.5, Feb 8, 2005. The ability to handle multiline
formulas was added.
Download
Version
Version 0.6, Sep 5, 2023
Author
 Peter Selinger, Dalhousie University (original author)
 Richard Zach, University of Calgary (current maintainer)
LICENSE
Copyright (C) 20022005 Peter Selinger
This work may be distributed and/or modified under the conditions of
the LaTeX Project Public License, either version 1.3 of this license
or (at your option) any later version. The latest version of this
license is in
https://www.latexproject.org/lppl.txt
and version 1.3c or later is part of all distributions of LaTeX
version 2008 or later.
Back to Homepage:
Peter Selinger /
Department of Mathematics and Statistics /
Dalhousie University
selinger@mathstat.dal.ca
/ PGP key