s/_as_Temporarily_Immutable/_as_temporarily_immutable/g, because the
latter is what the code actually does.
diff --git a/Doc/lib/libsets.tex b/Doc/lib/libsets.tex
index 74d09c7..865a9a1 100644
--- a/Doc/lib/libsets.tex
+++ b/Doc/lib/libsets.tex
@@ -199,14 +199,14 @@
A similar mechanism is needed by the \method{__contains__()} and
\method{remove()} methods which need to hash an element to check
for membership in a set. Those methods check an element for hashability
-and, if not, check for a \method{_as_Temporarily_Immutable()} method
+and, if not, check for a \method{_as_temporarily_immutable()} method
which returns the element wrapped by a class that provides temporary
methods for \method{__hash__()}, \method{__eq__()}, and \method{__ne__()}.
The alternate mechanism spares the need to build a separate copy of
the original mutable object.
-\class{Set} objects implement the \method{_as_Temporarily_Immutable()}
+\class{Set} objects implement the \method{_as_temporarily_immutable()}
method which returns the \class{Set} object wrapped by a new class
\class{_TemporarilyImmutableSet}.