diff --git a/mkessler-operators.sty b/mkessler-operators.sty
index 16540a4..0424146 100644
--- a/mkessler-operators.sty
+++ b/mkessler-operators.sty
@@ -138,3 +138,4 @@
 \DeclareMathOperator{\res}{res}
 \DeclareMathOperator{\infl}{inf}
 \DeclareMathOperator{\cov}{cov}
+\DeclareMathOperator{\cor}{cor}