diff --git a/operators.sty b/operators.sty
index eb6962e..63070cf 100644
--- a/operators.sty
+++ b/operators.sty
@@ -91,5 +91,10 @@
 
 
 \DeclareMathOperator\lhs{LHS}
+\DeclareMathOperator\card{card}
+\DeclareMathOperator\Cd{Cd}
+\DeclareMathOperator\Ord{Ord}
+\DeclareMathOperator\otp{otp}
+\DeclareMathOperator\Card{Card}