# newtxmath set braces

The behavior of set braces in newtxmath has recently changed for me. I can't find any indication of this change in the documentation. I'm wondering what has happened, if it might be a bug, and if the previous behavior (which I was fond of) is easily restored.

Previously, the midway point in the brace was (infamously) subtle, which led to the inclusion of the cmbrace option, discussed in the documentation. But now cmbrace seems to be the default, and I don't see a way to turn it off. The following produces the same output regardless of whether cmbrace is on or off (and toggling bigdelims has no effect):

\documentclass{article}
\usepackage{newtxtext}
\usepackage[cmbraces]{newtxmath}
\begin{document}
$\{$\{
\end{document}


The braces in normal mode are close to the previous math braces, though not identical.

If you look at the documentation Chapter 14 "Appendix: Changes made in version 1.5" you find the innocent looking

The overly small delimiters ([{ in Times are no longer used in math mode, being replaced by bigger versions. The former option bigdelims no longer has any effect.

What does this have to do with cmbraces? After this change, bigdelim is the default and bigdelim overwrites cmbraces, therefore cmbraces is now ignored. You could get back to cmbraces my manually adding

\DeclareMathDelimiter{\lbrace}{\mathopen}{lettersA}{62}{largesymbols}{142}
\DeclareMathDelimiter{\rbrace}{\mathclose}{lettersA}{63}{largesymbols}{143}


to your preamble, but as far as I can tell the original braces have been overwritten in the font, so they can not be restored without changing the font.

• Well spotted, that does seem to solve it. This seems like a less than ideal way to have implement this change. I can understand changing the default behavior, but making it impossible to revert to the old behavior? – Simon C Mar 11 '19 at 22:14