Remove "there" in "guarantee that there all"

Fixing error spotted by Hans.

chapters/operatorsandexpressions.tex

@@ -1395,7 +1395,7 @@ \subsection{Discrete-Time Expressions}\doublelabel{discrete-time-expressions}
 relations/functions that should generate events.
 
 \begin{nonnormative}
-The restriction above is necessary in order to guarantee that there all equations for discrete variable are discrete-time expressions, and to ensure that crossing
+The restriction above is necessary in order to guarantee that all equations for discrete variable are discrete-time expressions, and to ensure that crossing
 functions do not become active between events.
 \end{nonnormative}