diff -r ec5090faf541 -r 5b7c85586eb1 src/HOL/Analysis/Affine.thy
--- a/src/HOL/Analysis/Affine.thy	Thu Dec 05 21:03:06 2019 +0100
+++ b/src/HOL/Analysis/Affine.thy	Fri Dec 06 14:36:11 2019 +0100
@@ -1,3 +1,5 @@
+section "Affine Sets"
+
 theory Affine
 imports Linear_Algebra
 begin