--- a/RelaxNG/publiquiz.rnc	dim. mai 24 19:12:25 2015 +0200
+++ b/RelaxNG/publiquiz.rnc	mer. mai 27 22:29:05 2015 +0200
@@ -245,9 +245,9 @@
 category.head = element head { category.head.content }
 
 category.head.content =
-   title,
-   shorttitle?,
-   subtitle*
+   title
+ & shorttitle?
+ & subtitle*
 
 # ~~~~~~ categories
 categories = element categories { categories.attributes, categories.content }