University of Calgary

Strict Conditional in LaTeX

Submitted by Richard Zach on February 14, 2007 - 2:42am.

I just had occasion to have to typeset Lewis's strict conditional symbol <img src="http://plato.stanford.edu/archives/win2004/symbols/fishhook.gif" alt="- in LaTeX. It turns out it isn't in the standard AMS fonts. Peter Smith's LaTeX for Logicians to the rescue! There I found:

  1. that the strict conditional symbol is in the fonts that are part of the txfonts and pxfonts packages, and
  2. that there is a wonderful 110 page/3 MB comprehensive listing of all LaTeX symbols (by Scott Pakin).

Now it turns out that the point of txfonts and pxfonts is to give you output in Times Roman and Palatino fonts, respectively, with matching math and symbol fonts. That's useful in itself--but if you happen to not want your document to be in Times or Palatino, you can still get \strictif by putting this in the preamble:

\DeclareSymbolFont{symbolsC}{U}{txsyc}{m}{n}
\DeclareMathSymbol{\strictif}{\mathrel}{symbolsC}{74}

Submitted by lumpy pea coat (not verified) on February 14, 2007 - 6:30pm.

Good to know!

Submitted by Anonymous (not verified) on February 17, 2007 - 8:35pm.

That's helpful! Is there a similar trick for typesetting the `box arrow' symbol that is sometimes used for the counterfactual conditional? I think it's called `\boxright' in pxfonts/txfonts.

Submitted by Richard Zach (not verified) on February 17, 2007 - 11:44pm.

Just look up the font and symbol declarations in txfonts.sty:\DeclareMathSymbol{\boxright}{\mathrel}{symbolsC}{128}

Submitted by Peter Smith (not verified) on February 22, 2007 - 9:01pm.

I've added (with acknowledgement!) your code for using symbols extracted from txfonts to LaTeX for Logicians. Thanks for that!

Submitted by google (not verified) on July 30, 2007 - 12:08pm.

ahuenno!

Submitted by Anonymous (not verified) on December 20, 2009 - 6:44pm.

Great! Any thoughts on how to do this for use with XeLaTeX instead? Thanks!