ABSTRACT
A careful exposition and development of these ideas can be found in Lelewer and Hirschberg (1987). The authors there present an extensive review of methods for data compression, distinguishing between general-purpose and semantic-dependent techniques. Generalpurpose techniques are characterized by the fact that they can be employed without any knowledge about the information content of
2 1. Introduction
the data. Semantic-dependent techniques, on the other hand, achieve compression by exploiting the particular nature of the data in order to reduce redundancy.
