No subject

functionality as a set of refinements providing more and better detail
as we move from bib record (a title) through MFHD (for our purposes,
general prediction source data, and legacy course-grained holdings
statements) and on to distributions (with holdings statements),
streams (with lists of issuances), items (with physical location) and
units (with unique physical identifiers).  Generally speaking, each of
these steps is dependent on the one before, but the finer grained
details are not required for the courser grained data to be used.
(That's not the direct reality for /setting up and creating/ the
controlled data in all cases -- there are downstream dependencies on
items for controlled holdings statements, for instance -- but the
conceptual model is sound and correct for display logic).