diff --git a/tex/misc/functions.tex b/tex/misc/functions.tex
index 9a098c9..d2b1d8d 100644
--- a/tex/misc/functions.tex
+++ b/tex/misc/functions.tex
@@ -39,6 +39,9 @@
 \newcommand{\mSteps}{n_\text{steps}}
 \newcommand{\mObsSteps}{\mSteps}
 
+\newcommand{\mActivity}{\Omega}
+\newcommand{\mObsActivity}{\mActivity}
+
 \newcommand{\mNN}{\text{nn}}
 \newcommand{\mKNN}{\text{knn}}
 \newcommand{\fPos}[1]{\textbf{pos}(#1)}