--- a/Doc/lib/libsys.tex	Tue Mar 07 10:12:59 1995 +0000
+++ b/Doc/lib/libsys.tex	Tue Mar 07 10:14:09 1995 +0000
@@ -88,7 +88,7 @@
 as thread switches and signal handlers.  The default is 10, meaning
 the check is performed every 10 Python virtual instructions.  Setting
 it to a larger value may increase performance for programs using
-threads.  Setting it to a value <= 0 checks every virtual instruction,
+threads.  Setting it to a value $\leq 0$ checks every virtual instruction,
 maximizing responsiveness as well as overhead.
 \end{funcdesc}