I am getting a weird black square in math mode instead of “i” in symbols like \lim or \inf [closed]

If I write the symbol \lim in math mode in beamer I get a weird black square instead of the "i"

It happen also with other symbols as \inf, but not with \sin. It seems to be related with symbols that accept subscripts below them. If the document class is article, there is no problem. By the way, I am compiling with pdflatex. Anyone has a clue of what is happening?

closed as unclear what you're asking by egreg, Stefan Pinnow, Phelype Oleinik, Bobyandbob, user31729 Feb 15 '18 at 13:20

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

• Welcome to TeX.SX! Please help us help you and add a minimal working example (MWE) that illustrates your problem. Reproducing the problem and finding out what the issue is will be much easier when we see compilable code, starting with \documentclass{...} and ending with \end{document}. – user36296 Feb 11 '18 at 23:46
• \documentclass{beamer} \begin{document} \begin{frame} $\lim$ \end{frame} \end{document} works fine, so please include a short example that allows us to reproduce your problem. – user36296 Feb 11 '18 at 23:47
• Are you perhaps using \usepackage[spanish]{babel} on a TeX Live before 2016? – egreg Feb 12 '18 at 0:21
• Hi, Thank you for the welcome. Glad to join the community, and I hope I can also give some help. With the proposed MWE, it is working fine. @egreg is right, if a set the Spanish language, then the "i" is replace by another symbol. Some other languages seems to be fine. My TeX Live is a version of 2015 included in Linux Mint 18. – Robert Feb 12 '18 at 8:17
• @Robert -- the solution you found is one i haven't seen before, so you could add a self-answer so that this question won't get deleted automatically for lack of an answer. – barbara beeton Feb 12 '18 at 18:15

As suggested, I am posting an answer to my own question. It is more likely a workaround, but it works. Here you can find that by using \usefonttheme{professionalfonts} the problem is solved and the accents in math environment when using Spanish are correctly handled.