I've recently come across this symbols from this paper. enter image description here

Could you inform what are the code of this K and X? I tried \mathcal K and \mathcal X to no avail.

  • 1
    it's \mathcal but the exact shape will depend on the font (just as the shape of all the letters varies according to the font) If you have the PDF of the text you can show you can see a list of all fonts used. Oct 15, 2021 at 10:00
  • @DavidCarlisle I have added the link to the paper. Could you have a look at it? I feel that the font is just as the one I usually use.
    – Akira
    Oct 15, 2021 at 10:03
  • yes that's just computer modern/amsfonts ad euler fonts note its arxiv so you can download the tex source (although I just looked at the font list in the pdf) Oct 15, 2021 at 10:10
  • 3
    try \mathcal with \usepackage{eucal} Oct 15, 2021 at 10:14

1 Answer 1


As @DavidCarlisle said: "try \mathcal with \usepackage{eucal}" and also here is the workable example for Your question:


$V \subseteq \mathcal{K} . \times$\\
Let $(\mathcal{X}, \tau)$

enter image description here

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