I am currently looking at Lamport's "document preparation system for LaTeX" (1994 edition) and I am surprised to see that some of the mathematical symbols are rendered differently in the book than when I use them in a document. For instance, \leftrightarrow (page 43) has shorters arrow heads in the book. I'm just curious : has something changed in the rendering of these symbols ?

Thank you !

\documentclass[10pt]{article} \begin{document} $\leftrightarrow$ \end{document}

enter image description here

  • 2
    what code are you using now? even if you are using cm fonts you will be using type1 versions not the metfaont version (I think Lamport's book used cm) Oct 29, 2021 at 19:18
  • I am using pdfTeX, Version 3.14159265-2.6-1.40.17 (TeX Live 2016) (preloaded format=pdflatex). I don'k know how to find which fonts are used, but I understand your comment and your answer makes sense to me, thank you ! Oct 29, 2021 at 19:25
  • 1
    the fonts used depend on the commands in your document not the pdftex version. You should be able to show a small one line document that has the arrow that you are asking about Oct 29, 2021 at 19:28
  • OK, I am using \documentclass[10pt]{article} \begin{document} $\leftrightarrow$ \end{document} Oct 29, 2021 at 19:34
  • ok that is a computer modern arrow Oct 29, 2021 at 19:40

1 Answer 1


The computer modern fonts were updated in 1992 with arrows in particular being updated, see D. Knuth's message


Many characters were improved in 1992, notably the arrows

The 1994 edition of The LaTeX book was still using the older versions.

Campa points out that the older arrow forms have been preserved in a font made available by the old-arrows package so

\begin{document} $\leftrightarrow$ \end{document}

enter image description here

  • 2
    You might want to mention the package old-arrows. Personally, I find the old arrowheads better (and they harmonize better with the ones by amsfonts); I always wondered whether the change was related to the printer capabilities of those times.
    – campa
    Oct 29, 2021 at 19:58
  • Thank you, that's exactly what happened, I checked the rendering of \delta as advised and indeed, the version of Lamport's book I am looking at is using the older version. Oct 29, 2021 at 19:58
  • @campa never noticed that package before, but done thanks Oct 29, 2021 at 20:08

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