--- a/text/ncat.tex	Mon May 31 12:44:19 2010 -0700
+++ b/text/ncat.tex	Mon May 31 13:27:24 2010 -0700
@@ -73,6 +73,15 @@
 For each flavor of manifold there is a corresponding flavor of $n$-category.
 We will concentrate on the case of PL unoriented manifolds.
 
+(The ambitious reader may want to keep in mind two other classes of balls.
+The first is balls equipped with a map to some other space $Y$.
+This will be used below to describe the blob complex of a fiber bundle with
+base space $Y$.
+The second is balls equipped with a section of the the tangent bundle, or the frame
+bundle (i.e.\ framed balls), or more generally some flag bundle associated to the tangent bundle.
+These can be used to define categories with less than the ``strong" duality we assume here,
+though we will not develop that idea fully in this paper.)
+
 Next we consider domains and ranges of morphisms (or, as we prefer to say, boundaries
 of morphisms).
 The 0-sphere is unusual among spheres in that it is disconnected.