diff --git a/Doc/lib/libstdtypes.tex b/Doc/lib/libstdtypes.tex
index f5314093c66..38440feae8a 100644
--- a/Doc/lib/libstdtypes.tex
+++ b/Doc/lib/libstdtypes.tex
@@ -144,7 +144,7 @@ Notes:
 
 \end{description}
 
-Objects of different types, except different numeric types, never
+Objects of different types, except different numeric types and different string types, never
 compare equal; such objects are ordered consistently but arbitrarily
 (so that sorting a heterogeneous array yields a consistent result).
 Furthermore, some types (for example, file objects) support only a