fix typo

report/src/sections/02-preliminaries.tex

@@ -283,7 +283,7 @@ \subsubsection{Parameter Update}
     \label{eq:omega}
 \end{equation}
 
-The numerator sums $\gamma_s(t)$ for all time steps $t$ where the observed value $o_t = o$., meaning the model is in state $s$ and emits the observation $o$.
+The numerator sums $\gamma_s(t)$ for all time steps $t$ where the observed value $o_t = l$., meaning the model is in state $s$ and emits the observation $l$.
 The denominator sums $\gamma_s(t)$ for all time steps $t$ where the model is in a given state $s$.