On 08/22/16 06:55, Antony Stone wrote:
On Monday 22 August 2016 at 15:46:41, Dianne Skoll wrote:
On Mon, 22 Aug 2016 06:04:49 -0700
Marc Perkel <supp...@junkemailfilter.com> wrote:
Set A - a finite set - has some members,
Set B - an infinite set - is everything that is NOT in Set A
Set B is a very special case of an infinite set. We're talking about
infinite sets in general.
Also, you have to realize that although set B is in principle infinite,
in practice it is not. Computers have finite memory, and although the
number of email tokens representable in the memory of a computer is very,
very, very large, it's not infinite.
I do not think that Marc is proposing to actually store set B in a computer
(or anywhere else).
Set B is simply a theoretical construct, defined as the inverse of Set A, and
to discover whether something is a member of it, you do not search through the
infinite set B for a match, you instead check all members of finite set A for a
non-match.
If nothing in Set A matches X, then X is a member of Set B.
Antony.
Anthony, Yes - I don't store Set B. I store Set A. B is defined by
what's NOT in A. So I test A and if it's not matched it's set B. Set B
is just a negative match on A.
--
Marc Perkel - Sales/Support
supp...@junkemailfilter.com
http://www.junkemailfilter.com
Junk Email Filter dot com
415-992-3400
