Theorem, Lemma, Proof, Postulate, Hypothesis, Proposition, Corollary, or other formal statement, identified as such with a label and usually made typographically distinct from the surrounding text.
The following, in order:
<label> Label (of an Equation, Figure, Reference, etc.), zero or one
<abstract> Abstract, zero or more
<kwd-group> Keyword Group, zero or more
One or more of any of:
Any combination of:
Ownership Elements