diff --git a/src/math/mathop.pysty b/src/math/mathop.pysty
index 241379c..06c0b12 100644
--- a/src/math/mathop.pysty
+++ b/src/math/mathop.pysty
@@ -127,6 +127,7 @@ __END_OPTIONS_X__
 \def\twedge{\vee} % Semantically correct macros for wedge product
 \def\tsmash{\wedge} % Semantically correct macro for smash product
 \DeclareSimpleMathOperator{sing}
+\DeclareSimpleMathOperator{cell}
 
 %Category Theory
 \DeclareSimpleMathOperator{Ob}