Apply some math formatting

chapters/equations.tex

@@ -939,11 +939,11 @@ \subsection{The Number of Equations Needed for Initialization}\doublelabel{the-n
 
 \begin{nonnormative}
 In general, for the case of a pure (first order) ordinary
-differential equation (ODE) system with n state variables and m output
-variables, we will have n+m unknowns in the simulation problem. The ODE
-initialization problem has n additional unknowns corresponding to the
+differential equation (ODE) system with $n$ state variables and $m$ output
+variables, we will have $n+m$ unknowns in the simulation problem. The ODE
+initialization problem has $n$ additional unknowns corresponding to the
 derivative variables. At initialization of an ODE we will need to find
-the values of 2n+m variables, in contrast to just n+m variables to be
+the values of $2n+m$ variables, in contrast to just $n+m$ variables to be
 solved for during simulation.
 \end{nonnormative}
 
@@ -957,17 +957,17 @@ \subsection{The Number of Equations Needed for Initialization}\doublelabel{the-n
 
 Here we have three variables with unknown values: two dynamic
 variables that also are state variables, \lstinline!x1! and \lstinline!x2!, i.e.,
-n=2, one output variable \lstinline!y!, i.e., m=1, and one input variable \lstinline!u! with
+$n=2$, one output variable \lstinline!y!, i.e., $m=1$, and one input variable \lstinline!u! with
 known value. A consistent solution of the initial value problem
 providing initial values for \lstinline!x1!, \lstinline!x2!, \lstinline!der(x1)!,
 \lstinline!der(x2)!, and \lstinline!y! needs to be found. Two additional initial
 equations thus need to be provided to solve the initialization problem.
 
-Regarding DAEs, only that at most n additional equations are
-needed to arrive at 2n+m equations in the initialization system. The
+Regarding DAEs, only that at most $n$ additional equations are
+needed to arrive at $2n+m$ equations in the initialization system. The
 reason is that in a higher index DAE problem the number of dynamic
 continuous-time state variables might be less than the number of state
-variables n. As noted in \autoref{initialization-initial-equation-and-initial-algorithm} a tool may add/remove
+variables $n$. As noted in \autoref{initialization-initial-equation-and-initial-algorithm} a tool may add/remove
 initial equations to fulfill this requirement, if appropriate
 diagnostics are given.
 \end{example}