# How to type the letter “i” with two dots (diaeresis) in math mode? [duplicate]

This question already has an answer here:

I would like to type the letter "i" in math mode, but with two (horizontally aligned) dots rather than with just one.

I know there is \ddot{i}, but that puts the two dots on top of the existing one, while \text{\"i} sets the letter in text form rather than in math mode. MWE:

\documentclass{article}
\begin{document}

\begin{align*}
f(x) = \ddot i \\
f(x) = \text{\"i}
\end{align*}

\end{document}


gives

How can I get the desired result? Thanks! (And I know that the two dots can lead to confusion with the second derivative.)

## marked as duplicate by egreg, lockstep, karlkoeller, Claudio Fiandrino, T. VerronJul 17 '13 at 9:13

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

• \ddot{\imath} – egreg Jul 17 '13 at 8:00
• @egreg Fast, concise and precisely what I needed - thank you! Do you want to turn it into an answer for acceptance? Couldn't get any better anyway, I guess... – Bernd Jul 17 '13 at 8:02
• The same applies to \jmath. – Martin - マーチン Jul 17 '13 at 8:26
• Um - should I leave or delete this question now, since I apparently overlooked the question @egreg pointed out? Should I accept Bernard's answer given below? Or should I wait for egreg to turn his comment into answer, since he was "first"? – Bernd Jul 17 '13 at 9:08
• @Bernd Leave it; it can be useful also if closed as duplicate. – egreg Jul 17 '13 at 9:19

## 1 Answer

\ddot{\imath} for mathitalic – or \ddot{\i} for mathroman.