diff --git a/mkessler-operators.sty b/mkessler-operators.sty
index 8154b9c..0757749 100644
--- a/mkessler-operators.sty
+++ b/mkessler-operators.sty
@@ -132,5 +132,5 @@
 %%Galoiskohomologie
 \DeclareMathOperator{\Br}{Br}
 \newcommand{\del}{\partial}
-
+\DeclareMathOperator{\EXT}{EXT}