Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!batcomputer!cornell!uw-beaver!mit-eddie!andante!alice!jj
From: jj@alice.att.com (jj, like it or not)
Newsgroups: comp.compression
Subject: Re: theoretical compression factor
Message-ID: <20135@alice.att.com>
Date: Thu, 28 Mar 91 16:50:12 EST
References: <1991Mar25.054838.15588@bingvaxu.cc.binghamton.edu> <1991Mar26.220519.1242@unislc.uucp> <1991Mar27.120829.26094@bingvaxu.cc.binghamton.edu>
Reply-To: jj@alice.UUCP (jj, like it or not)
Organization: NJ State Home for Bewildered Terminals
Lines: 19

Please, folks, you're confusing several issues here.

First, the question of "how much can I compress X" must
be qualified.  If you have a historyless compression,
you can compress up to the entropy ( sum of -p log p) bound,
where p is the probability of each token.

If you have history in your compression algorthm, you may (or
may not) be able to do better, depending on the randomness
of your token distribution (even given a fixed distribution of
tokens).

You must separate the two issues, and be sure to mention which
(or what) bound you refer to.
-- 
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