<!ENTITY % mathstructure
'(ht:AXIOM|ht:DEFINITION|ht:THEOREM|ht:VARIABLE|ht:SECTION|ht:MUTUAL)*'>
+<!ELEMENT ht:OBJECT EMPTY>
+<!ATTLIST ht:OBJECT
+ uri CDATA #REQUIRED
+ mode (typeonly|embed|linkonly) #REQUIRED>
+
<!ELEMENT ht:AXIOM EMPTY>
<!ATTLIST ht:AXIOM
uri CDATA #REQUIRED