# Is there a convention that forbids paragraph break immediately after a displayed math formula?

Is there any typographical rule or convention that forbids paragraph break right after a displayed math formula?

For example see this code where the first displayed math formula does not have any paragraph after it and the second displayed math formula has a paragraph break right after it:

\documentclass{article}
\begin{document}
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec lectus
velit, dapibus ut eleifend quis, condimentum eu elit. Curabitur
scelerisque orci at lectus aliquet mattis ut ultrices massa.
$$1 + 1 = 2$$
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec lectus
velit, dapibus ut eleifend quis, condimentum eu elit. Curabitur
scelerisque orci at lectus aliquet mattis ut ultrices massa.

$$1 + 1 = 2$$

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec lectus
velit, dapibus ut eleifend quis, condimentum eu elit. Curabitur
scelerisque orci at lectus aliquet mattis ut ultrices massa.

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec lectus
velit, dapibus ut eleifend quis, condimentum eu elit. Curabitur
scelerisque orci at lectus aliquet mattis ut ultrices massa.
\end{document}


Here is the output:

Is there any rule or convention that forbids the second displayed math formula that is followed immediately by a paragraph break.

I tried searching through a couple of popular math books published by Springer I have but I could not find a single instance of a displayed math formula immediately followed by a paragraph break and that is what made me wonder if such a style is forbidden.

• – Werner Dec 26 '20 at 19:19
• It's not forbidden, why should it be? If the text after the display starts a new paragraph, then let it be. To the contrary, starting a paragraph with a display is not good practice. The asymmetric spacing you get in the second instance is caused by the blank line before the display. – egreg Dec 26 '20 at 19:53

You should not use  in LaTeX, also you should not have a blank line before the display, having a paragraph break after the display is fine if the following text starts a new paragraph, although not ending a sentence with a displayed equation ovoids the old issue of how best to place the end of sentence punctuation.