ps: I have asked this question on (here) but is regarded as off-topic. So I moved it here.
I have seen different ways in papers to put comma after equation.
right after the equation:
right before
where:no comma at all:
Which way should I choose? Which way is more standard?
1 Answer
The first variant is correct (though this is a question on typography rather than math).
More precisely, if you would place a comma with non-display formulas (or if the formula where a normal sequene of words) the you also should place a comma with a display formula. The same holds for periods. However, in TeX you would set the comma or other interpunction after the single dollar ("$a=b$, where"), but before the double-dollar ("$$a=b,$$ where") for the very reason that variant two must be avoided. Sometimes switching from inline to display causes variant two by mistake.
