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- Huffman maps
fixed length symbols to variable length codes. Optimal only when symbol
probabilities are powers of 2.

- Arithmetic maps entire message to real number range based on
statistics. Theoretically optimal for long messages, but optimality
depends on data model. Also can be CPU/memory intensive.

- Lempel-Ziv-Welch is a dictionary-based compression method.
It maps a variable number of symbols to a fixed length code.

- Adaptive algorithms do not need a priori estimation of probabilities,
they are more useful in real applications.

*Dave Marshall*

*10/4/2001*