Declaring a newcommand for a single letter in mathcal

Question

I am trying to enter a command that references the \mathcal font for single letter in LaTeX. Below is what I am trying and it doesn't seem to work, would appreciate any help.

 \newcommand {\until} {\mathcal {u} }

I believe by doing this, when I type \until it should apply the u in the desired font.

Answer 1

Use capital letter(s) U.

\documentclass{scrartcl}
\newcommand{\until} {\mathcal{U} }

\begin{document}

$\until$
\end{document}