ABSTRACT
Information theory—sometimes called communication theory—is a new and rapidly growing branch of mathematical science. Its beginning can best be dated from the publications by N. Wiener and C. E. Shannon in 1948, although earlier roots can be traced. The theory tries to study communication in the abstract—a concept far removed from the normal understanding of communication. Information theory regards communication as transmitting and receiving symbols from a given ‘vocabulary’ which are drawn at random, but with specified probabilities. The symbols may be discrete as with letters or words, or continuous as with radio wave-forms. When speech is transmitted by telephone, for instance, it is encoded into an electrical series by the instrument. The measure of sorting effectiveness developed above—the logarithm of the number of separations—may be multiplied by the cost function for sorting to establish the efficiency of the sorting.
