diff --git a/src/math/mathop.pysty b/src/math/mathop.pysty
index 0c5c3b1..1f04705 100644
--- a/src/math/mathop.pysty
+++ b/src/math/mathop.pysty
@@ -120,6 +120,7 @@ __END_OPTIONS_X__
 \DeclareSimpleMathOperator{pr}
 \def\twedge{\vee} % Semantically correct macros for wedge product
 \def\tsmash{\wedge} % Semantically correct macro for smash product
+\DeclareSimpleMathOperator{sing}
 
 %Category Theory
 \DeclareSimpleMathOperator{Ob}