-<!ELEMENT InTheory (%queryexpr;, ItemType)>
-
-<!ELEMENT ItemType EMPTY>
-<!ATTLIST ItemType
- binder CDATA #REQUIRED>
-
-<!ELEMENT TheoryRefTo %queryexpr;>
-
-<!ELEMENT TypeOf %queryexpr;>
-<!ATTLIST TypeOf
- binder CDATA #REQUIRED>
-
-<!ELEMENT SuperTypeOf %queryexpr;>
-<!ATTLIST SuperTypeOf
- binder CDATA #REQUIRED>
-
-<!ELEMENT SubTypeOf %queryexpr;>
-<!ATTLIST SubTypeOf
- binder CDATA #REQUIRED>
-
-<!-- MathQL query sub-expressions -->
-
-<!ELEMENT SortField %functexpr;>
-<!ATTLIST SortField
- order %order; #IMPLIED>
-
-<!ELEMENT In %queryexpr;>