# suppress indentation only after equation in LaTeX

I am trying to make my LaTeX document only have indentation after equations. Other cases, including any lines of a paragraph block, no indentation.

This is a paragraph block that has many lines and I don't want indentation of any lines.

equations 1 here

Only the first line after equation need indentation. If this block has many lines, no indentation after first line.

Edited:

Sorry I am new to this site. Here is the example I created. Hope that I addressed my problem clearly. Sorry for any inconvenience.

\documentclass[12pt]{article}

\setlength\parskip{12pt}

\begin{document}

I need help on this problem: indentation only after equation. For example, this is a paragraph not directly following an equation. Then it has no indentation to any of its lines.
$$a = b+c$$
This sentence directly follows an equation. Indentation is needed for the first line, only.
$$a = b*c$$

This sentence starts a new paragraph, though directly follow an equation but no indentation for first line. Thanks.

Then I start a new paragraph. This paragraph, again, doesn't directly follow an equation. No indentation need.
I read an answer talking about blank line after equation. I understand this case. If I suppress a blank line after equation, it could give me indentation after equation. But it also gives me indentation of first line of every paragraph, which is not I wish to do.

I have a silly solution that just add indent command to every sentence I want it indented. My question is could I have a worldwide solution? Thanks very much.

\end{document}

• Hopefully you write your equations with no space (empty lines) following them, right? – Werner Oct 14 '14 at 6:45
• Welcome to TeX.SX! Please help us to help you and add a minimal working example (MWE) that illustrates your problem. It will be much easier for us to reproduce your situation and find out what the issue is when we see compilable code, starting with \documentclass{...} and ending with \end{document}. – yo' Oct 14 '14 at 8:24
• As Werner mentions, blank line means new paragraph, so if you do not need a new paragraph after an equation, then suppress the blank line. – daleif Oct 14 '14 at 8:31
• Your post was migrated here from another Stack Exchange site. Please register on this site, too, and make sure that both accounts are associated with each other (by using the same OpenID), otherwise you won't be able to comment on or accept answers or edit your question. – Johannes_B Oct 14 '14 at 8:48
• Either you indent all new paragraphs or none (all is better). Indenting a line between two equations doesn't make any sense; the first line after an equation should be indented only if it starts a paragraph (which usually doesn't). – egreg Oct 14 '14 at 15:21

This is very strange request. But why not? You have set \parskip to 12pt, so the paragraphs are visible by this horizontal space. You can put the following three lines to your preamble:
\parindent=0pt