# Is this a bug in LaTeX?

I have tried to use this symbol in one of my equations:

\mathfrak{\mathcal{l}}


But, instead of showing that letter in mathcal and mathfrak styles, it shows updownarrow?!

I mean: \mathfrak{\mathcal{l}} gives exactly the same command of \updownarrow

Is it something wrong going here or there is a logical explanation?! I have checked it in WinEdt and also in the following online LaTeX equation editor: https://www.codecogs.com/latex/eqneditor.php

Both give the same result!!

Thank you so much

• \mathfrak and \mathcal are not ornaments to a font (in the manner of \hat or \dot). Rather, they are separate fonts in themselves. Thus, it makes no sense to try to combine them as you did. – Steven B. Segletes Sep 29 '19 at 22:46
• also the is no lowercase mathcal. See tex.stackexchange.com/questions/231322/… if you need a caligraphic. – c.p. Sep 29 '19 at 22:46
• What would a calligraphic fraktur letter be? (Accepting of course fraktur is a kind of calligraphy, but a very different kind to the loopy kind represented by \mathcal) – Au101 Sep 30 '19 at 1:12
• Your second question is completely separate from the first one, and in general it's better to make two posts in such cases. – Torbjørn T. Sep 30 '19 at 16:11
• Thanks for all these amazing comments .. Yeah, sure, the second part is separated and it can be found here: tex.stackexchange.com/questions/510483/… – Sitra Oct 1 '19 at 0:51

Math alphabets don't combine, so with

\mathfrak{\mathcal{l}}


you get exactly the same as with

\mathcal{l}


which yields a “random” symbol, because \mathcal only has effect on uppercase letters.

• Unless you load unicode-math, which does have 𝓵, 𝕝 and 𝖑. – Davislor Oct 1 '19 at 4:57