[Tex/LaTex] Proper punctuation after cases environment

casesmath-modepunctuationtypography

I know that when writing a displayed equation, it's correct to write punctuation before the closing \] as follows:

This proves \[ x^2 = 3, \] and it follows that \[ x = \pm\sqrt{3}. \]

If I'm using a cases environment, where's the correct place for the period to end the sentence?

Absolute value is defined as \[ \lvert x \rvert = \begin{cases}
  x & \text{if $x \ge 0$} \\
  -x & \text{if $x < 0$}
\end{cases} \]

If I put it after the cases environment, it looks funny. If I leave it off completely, then it also looks bad. It looks okay to put it at the end of the second line ($x < 0$.}), but are there any better solutions?

Best Answer

You've pretty much enumerated all the sensible options in your question, so I don't know that there's anything else. What I've seen sometimes (IIRC) is to put a comma after each case, and then I guess the period could go at the end of the last one.

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