meta CDATA #IMPLIED
>
-<!-- ROOT -->
-
<!ELEMENT ENTITY %entity;>
<!ATTLIST ENTITY
hierarchy NMTOKEN #REQUIRED
options NMTOKENS #IMPLIED
>
+
+<!-- CONVERSION CONSTRAINT SYSTEM -->
+
+<!ENTITY % ccs '(ToInfinity)'>
+
+<!ELEMENT ToInfinity EMPTY>
+<!ATTLIST ToInfinity
+ arity NMTOKEN #IMPLIED
+ mark NMTOKENS #IMPLIED
+>
+
+<!ELEMENT CCS %ccs;>
+<!ATTLIST CCS
+ uri CDATA #REQUIRED
+>