Re: Oids

From: Vadim Tropashko <vadimtro_invalid_at_yahoo.com>
Date: 17 Aug 2005 14:41:57 -0700
Message-ID: <1124314917.283480.204740@g44g2000cwa.googlegroups.com>

Summarising:

header(A) = a0 = 00 join A
rowids(A) = Ox = 00 union A

(Change 'rowids' to 'foo' if you like. Although I find a little comfort with informal idea that header can be viewed is an additional hidden row in the table, while the list of rowids is an additional hidden column).

Now, it seems that you hit the nail, and the rowid maps Relational Lattice into a boolean algebra with just 2 elements 00 and 01. This is dual to header lattice homomorhism of Relational Lattice into a boolean algebra of sets. The symmetry is sligtly broken, but who would insist that rows and columns are completely symmetrical? Received on Wed Aug 17 2005 - 16:41:57 CDT