Lucid statement of the MV vs RM position?

A number of people on this group are proponents of Pick (MultiValue) DBMS. I've been trying to find a definition for MultiValue to give me a better handle on the arguments MV types often advance against the relational model.

As I understand it, an MV database is a collection of files, a file is a collection of records, records in a file all have the same structure, a record is indexed by a unique key, a record is a collection of fields, a field is a collection of (atomic?) values.

If that is correct, it seems to me that MV is an implementation technology and the RM is a logical formalism and that to compare the two is to compare apples and oranges.

That said, debate on the topic still goes on and on in this group, so I assume I have failed to grasp something important about MV. Is there a clear, *concise* explanation somewhere of (a) a formal
(preferably set theoretic) model of MV, and (b)
how integrity constraints are expressed and enforced in an MV database?

(On www.pickwiki.com I came across "A formal
mathematical critique of Relational Theory and its MultiValue opposition", which I hoped would be a lucid expression of the MV vs RM position, but unfortunately it turned out to be just plain wrong where it wasn't incoherent.)

• Ralph