# How to write properly math accent for letter i?

When it is requested to write letter "í" in math mode, it happens that $\acute{i}$ is not the right answer as it could be expected: the accent (´) is written over the letter (i), without deleting/overwriting the upper dot (^{.}) Another possiblity to solve the problem: $\acute{\imath}$, not always works satisfactorily. Is there another way to do it, obtaining an acceptable/appropriate character?

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$\acute{\imath}$ is the right way. What do you mean by "not always works satisfactorily"?

In general, \imath and its companion \jmath should be used for the math accents:

• \acute{\imath}
• \grave{\imath}
• \dot{\imath} (ambiguous!)
• \ddot{\imath}

and so on.

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What is the difference between your suggestion and those one wrote on the question? –  Sigur Aug 30 '12 at 1:00
Well, what I want to say is the next: when you have the expression $X_{\rm s\acute\imath}$, the grammar is more or less ok, but not completely correct, because the second letter is not in \rm. Is it feasible to write completly the subscript in normal text (e.g. roman)? –  paritto6 Aug 30 '12 at 3:13
@paritto If you need a textual subscript, use $X_{\textup{si}}$ or $X_{\textup{sì}}$ (if you are using inputenc); this needs the amsmath package. –  egreg Aug 30 '12 at 9:44
@egrep: Just \text as I know. When using \textup, amsmath is not needed. –  Leo Liu Aug 30 '12 at 9:50
@LeoLiu With amsmath, \textup will take care of the size in a subscript; without the package it wouldn't. With \text the current font will be used, with \textup` the upright shape will certainly be selected. –  egreg Aug 31 '12 at 9:34