# Are there two different versions of the \mathcal{F} character?

I've seen two different versions of the \mathcal{F} character:

Version 1:

Version 2:

Notice that the top horizontal line of the F curves down on the left much more in version 1 than it does in version 2.

Which of these is the preferred \mathcal{F}? I know that some of the calligraphic capital letters were improved at one point, but I don't know which version is the improved one.

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Hi MSC, please note that you can include images using one of icons on top of the edit box. You have now enough reputation points to do this. –  Martin Scharrer Feb 16 '11 at 23:19

The final version of Computer Modern's mathcal F is the second one. To see it, you can compile with metafont the file cmsy10.mf (located in [texmf]/fonts/source/public/cm/; be sure you have the latest version). Here is the result, after conversion in dvi format with gftodvi:

If you compare the type 1 versions of Computer Modern, you see that the Bluesky/AMS and Latin Modern versions both have the right version. However, old versions of Latin Modern have the wrong mathcal F:

This means that if you use a recent TeX distribution, you should always have the final version ofthe mathcal F.

As an aside, my version of Computer Modern Typefaces, although recent, still shows the old version:

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Thank you. Is there also a new-style bold \mathcal{F}? My system uses the new-style normal \mathcal{F} but the old-style bold \mathcal{F}. I've noticed this discrepancy in a few other PDFs I've found on the web, too. –  MSC Mar 10 '11 at 17:40
@MSC: yes, the bold also has a new version, but it's not in the Bluesky/AMS fonts. You can find it in the latest version of Latin Modern. So if your TeX distribution is recent, using \usepackage{lmodern} will ensure you're using the latest versions. –  Philippe Goutet Mar 10 '11 at 20:24