diff --git a/main/cs.tex b/main/cs.tex
index 4cf4963..78b4bb0 100644
--- a/main/cs.tex
+++ b/main/cs.tex
@@ -26,3 +26,4 @@
 \newcommand{\tC}{\text{C}}
 \newcommand{\tN}{\text{N}}
 \newcommand{\bigvdash}[2]{\sststile{#1}{#2}}
+\newcommand{\class}{\text{\tr{Cl}{Kl}}}