Mandatory @xml:id attribute on the root TEI element?

[daliboris]

The @xml:id attribute is mandatory on the <entry> element for referencing (usually within the dictionary itself, but not always).

Should this attribute also be mandatory for the root element <TEI> for referencing the whole dictionary?

For example second edition of the same work.

[laurentromary]

Well @xml:id is intended to identify a unique element within a document (it's a core XML mechanism) and it makes no real sense to have it on a root element. The exception would be, taking up your use case, if you have two editions within a <teiCorpus> with more than one <TEI> element inside. If you really want to attach a unique identifier, you should have it within an <idno> in the <publicationStmt> of your document.