I am using Latex. I want to write x as in Polykov's book, but I do not konw which font it is.
It is like chi, but it is not.
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Sign up to join this communityIt seems to be Bitstream Charter text with Math Design math.
It is just an x, not chi.
Use \usepackge[charter]{mathdesign}
to employ this type of font.
More information about free fonts in Latex, see enter link description here
The xcharter
package has five different recommended preambles for this font, all of them for PDFLaTeX. The disadvantage of using mathdesign
is that it breaks mathalpha
, making it difficult to replace the default \mathcal
with a better one.
If you’re using the modern toolchain, you would load the letters of XCharter over your math font, for example:
\documentclass{book}
\usepackage[math-style=ISO]{unicode-math}
\defaultfontfeatures{Scale=MatchLowercase}
\setmainfont{XCharter}[Scale=1.0]
\setmathfont{Libertinus Math}
\setmathfont[range=it]{XCharter Italic}
\setmathfont[range=up]{XCharter Roman}
\setmathfont[range=bfit]{XCharter Bold Italic}
\setmathfont[range=bfup]{XCharter Bold}
\newcommand\dint[1]{\mathop{\mathrm{d}{#1}}}
\begin{document}
\[ G \left( x, x' \right) =
\int \left( \frac{\mathcal{D} x(\tau)}{\mathcal{D} f(\tau)} \right)
\exp \left( -m_0 \int\limits_0^1
\left(\dot{x}^2 (\tau)\right)^{1/2}
\dint{\tau}
\right)
\]
\end{document}
XCharter is a fork of the free version of Charter that Bitstream donated to the X Consortium in 1992. One disadvantage is that v and ν (nu) might be too similar. Charis SIL is another free font based on Charter.
(Thanks to Sebastiano for some tips on better matching the typesetting of the book. You might try \frac{1}{2}
or \sfrac
from xfrac
instead of {1/2}
.)