# Commas in \cases - typographic standards?

I'm wondering what are the typographic standards for the placement of commas/dots in the following (and similar) case:\

The first option looks nicer, the second seems to be more logically consistent.

• In the TeXbook Knuth uses something like $$d=\begin{cases} (l+b)^2+p^2,&\text{if 0\le p<10000};\\ (l+b)^2-p^2,&\text{if -10000<p<0};\\ (l+b)^2,&\text{if p\le-10000}.\end{cases}$$. See also tex.stackexchange.com/q/499/35864 Dec 21, 2019 at 20:31
• You may also be interested in what the AMS style guide has to say on the issue (ams.org/arc/styleguide/AMSstyleguide.pdf, §13.11) Dec 21, 2019 at 20:36
• I don't find the second option logically consistent, besides being typographically abominable. Dec 21, 2019 at 21:15
• My goto rule for this is to use the same punctuation that you'd use if this wasn't in display mode, aka the first one. Dec 21, 2019 at 21:22