Post #1666326
2026-04-20 14:00 UTC
Attached is a typographical failure which I encountered in a book from a respected academic publisher.
Less-than and greater-than symbols < > have been used instead of angle brackets ⟨ ⟩ (\langle and \rangle).
This error should not have survived editorial scrutiny. Even if the author preferred the *appearance* of less-than and greater-than symbols, the real problem is that TeX spaces them as binary relations rather than delimiters.
Thus there is no space between = and <, but a space is inserted after < and before >. (In inline math, line breaks could occur in the inserted spaces.)
With angle brackets, TeX inserts a medium space between = (a binary relation) and ⟨, and no space after ⟨ or before ⟩.
I imagine the use of < and > instead of ⟨ and ⟩ could cause problems for screen readers as well, but I do not know for sure.
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#TeXLaTeX #typography #rant
Replies (1)
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@ajcain@mathstodon.xyz 2026-04-20 14:01
In technical terms, are classified as ‘Bin’ (binary relations) math atoms, while angle brackets are classed as ‘Open’ and ‘Close’ math atoms (opening and closing delimiters). TeX automatically spaces different kinds of math atoms according to their types (see the table in chapter 18 of ‘The TeXbook’). If one really wanted to use symbols identical to as angle brackets, one could redefine the \langle and \rangle commands to (respectively) \mathopen{}. The \mathopen{...} and \mathclose{...} commands make TeX treat the subformula in the parameter as (respectively) an ‘Open’ and ‘Close’ math atom. 2/2