Re: questions about entities and entity declarations

>* should XML require all entities to be synchronous with the document's
>logical structure?


>* if XML makes DTDs optional and allows partial DTDs, what must or may a
>parser do when it encounters references to undeclared entities (9.4)?
>Should XML declare any set of entities automatically?

Step 1. Look for the entities in a catalog by name:

     &bar; --> ENTITY "bar" "http://www.ebt.com/bar.sgml"

Step 2. Look in a position relative to the document instance for
        a file of the same name with an .sgml or .sgm or no extension 
>* if XML uses ISO 10646, should there be a special form of character
>reference using hexadecimal, not decimal, numbers, since most references
>to ISO 10646 and Unicode use hex, not decimal (9.5)?

Use Rick's optimised form: &UXXXXXXXX;