LaTeX macros for Fitch style natural deduction

Fitch-style 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 easy-to-use 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:

  \hypo {1} {\forall y \neg P(y)}
  \hypo {2} {\exists x P(x)}
  \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}
  \have {6a}{\bot}                 \Ee{2,3-6}
  \have {7} {\neg \exists x P(x)}  \ni{2-6a}
The output is shown on the left, and the corresponding LaTeX code on the right.


Version 0.5, Feb 8, 2005. The ability to handle multi-line formulas was added.



Version 0.5, Feb 8, 2005


Peter Selinger, University of Ottawa

Web links

A similar package by another author is


Copyright (C) 2002-2005 Peter Selinger

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

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Peter Selinger / Department of Mathematics and Statistics / Dalhousie University
selinger@mathstat.dal.ca / PGP key