--- a/ttml10/spec/ttaf1-dfxp.xml	Fri May 17 22:00:24 2013 -0600
+++ b/ttml10/spec/ttaf1-dfxp.xml	Sat May 25 18:47:55 2013 -0600
@@ -839,6 +839,9 @@
 fragment, using the Kleene operators <code>?</code>, <code>*</code>
 and <code>+</code>. Each element name therein is a hyperlink to its
 own illustration.</p>
+<p>The term linear white-space (LWSP) is to be interpreted as a non-empty sequence of
+SPACE (U+0020), TAB (U+0009), CARRIAGE RETURN (U+000D), or LINE FEED (U+000A),
+which corresponds to production [3] <code>S</code> as defined by <bibref ref="xml10"/>.</p>
 <p>All content of this specification that is not explicitly marked as
 non-normative is considered to be normative. If a section or appendix
 header contains the expression "Non-Normative", then the entirety