is there a tex font set for this kind of curly alphabet?

the symbols comes from this post

is there a tex font set for this kind of curly alphabet?

• Welcome to TeX.SX! It looks like eulervm with \mathcal: \documentclass{article} \usepackage{eulervm} \begin{document} $\mathcal{F}_n and \mathcal{G}_n$ \end{document} – Phelype Oleinik Jul 11 '19 at 0:06
• @PhelypeOleinik thanks man, plz move or copy your comments to answer, I'll accept it. – fu DL Jul 11 '19 at 0:25

The font is the caligraphic font from the Euler Virtual Fonts (eulervm). If you load the eulervm package the text looks quite similar to the screenshot:

However the subscript n from the linked PDF doesn't look like Euler's, but Computer Modern. You can load Euler for the \mathcal alphabet only with \usepackage[cal=euler]{mathalpha} (notice the difference of the subscript n):

Code:

\documentclass{article}
\usepackage[margin=4cm]{geometry}
% \usepackage{eulervm}
\usepackage[cal=euler]{mathalpha}
\begin{document}
\pagestyle{empty}
\begin{description}
\item [Hypothesis Space] Term used in the machine learning literature.
It denotes the space $\mathcal{F}_n$ of classifiers, or the space
$\mathcal{G}_n$ of conditional probabilities, from which the learning
algorithm selects a hypothesis.
\end{description}
\end{document}

• It is the same, well done! Off-topic. How did you produce LaTeX text without background? In imgur it is a png image, but it seems that you have compiled it using svg extension, which I love. – manooooh Jul 11 '19 at 0:57
• @manooooh I compiled a normal pdf and used ImageMagick: convert -trim -density 150 texsx.pdf texsx.png. The PDF doesn't actually have a background color, so ImageMagick doesn't add one when converting to png. – Phelype Oleinik Jul 11 '19 at 1:04
• +1. :-) Another way to load the Euler math-calligraphic letters without changing the other math fonts is to run \usepackage[cal=euler]{mathalfa} in the preamble. I find this a bit more mnemonic than \DeclareMathAlphabet{\mathcal}{U}{eus}{m}{n}. :-) – Mico Jul 11 '19 at 2:12
• @Mico I didn't know of mathalfa (which actually just redirects to mathalpha). Indeed, much easier to remember. Thanks :-) – Phelype Oleinik Jul 11 '19 at 5:12
• You can also load the OpenType font Neo Euler in unicode-math. It contains the same \mathcal alphabet. – Davislor Jul 11 '19 at 7:49