copy edit ch 12

book.tex

@@ -22229,8 +22229,8 @@ types.
 {\if\edition\pythonEd\pythonColor
 %
 In Python, when writing a generic function such as \code{map}, one
-does not explicitly write down its generic type (using \code{All}).
-Instead, the fact that it is generic is implied by the use of type
+does not explicitly write its generic type (using \code{All}).
+Instead, that the function is generic is implied by the use of type
 variables (such as \code{T}) in the type annotations of its
 parameters.
 %
@@ -23156,7 +23156,7 @@ The source type of the cast is the erasure of $T$, the type $T_s$.
 {\if\edition\racketEd
 %
 The target type $T_t$ is the result of substituting the argument types
-$ts$ for the type parameters $xs$ in $T$ followed by doing type
+$ts$ for the type parameters $xs$ in $T$ and then performing type
 erasure.
 %
 \begin{lstlisting}
@@ -23171,7 +23171,7 @@ and $s = \LP\code{map}~\code{cons}~xs~ts\RP$.
 {\if\edition\pythonEd\pythonColor
 %
 The target type $T_t$ is the result of substituting the deduced
-argument types $d$ in $T$ followed by doing type erasure.
+argument types $d$ in $T$ and then performing type erasure.
 %
 \begin{lstlisting}
 Inst(|$e$|, |$d$|)