At 5:29 PM 9/25/95, David Van Wie wrote:

David Van Wie wrote:

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The entropy E is defined by the sum across n states of -P_i log_2(P_i),

Timothy C. May wrote:

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Hah! Another physicist converted to the information-theoretic view of entropy!

Indeed. I was able to track down the literature, and it is most interesting. I am still a little bit skeptical of the "superset including thermodynamic entropy" school of thought, but I haven't finished reading all of the materials yet! Clearly, the IT "version" of entropy is a well defined and useful thing....

Well, the more you adapt to the information theory point of view, the more the Shannon-Kolmogoroff-Chaitin definitions become the natural ones, then the more the whole "thermodynamic" definition of entropy will seem the odd one. One is left with the conclusion that Gibbs-style entropy has _something_ fundamental to do with information theory, and can then consider what those relationships may be. But, perforce, one is left with the most basic interpretation of algorithmic complexity: the complexity of a system is related to the length of the algorithm describing it. A "random" system is one which has no shorter algorithmic description than itself. (The connection of this statement to IQ test questions about describing a sequence is left as an IQ test question for the reader.) --Tim May ---------:---------:---------:---------:---------:---------:---------:---- Timothy C. May | Crypto Anarchy: encryption, digital money, tcmay@got.net 408-728-0152 | anonymous networks, digital pseudonyms, zero Corralitos, CA | knowledge, reputations, information markets, Higher Power: 2^756839 | black markets, collapse of governments. "National borders are just speed bumps on the information superhighway."