VARIABLE LENGTH PREFIX ENCODING.

The problem of constructing minimum-redundancy prefix codes for the general discrete noiseless channel without constraints is considered for unequal code letter costs. Two cases are considered the symbols encoded are assumed to be equally probable, and the symbols encoded are not restricted to be equally probable. A graphical technique is developed for solving the problem for which the code words are equally probable and are constructed from r symbols where r or 2. The solution technique is valid either in the presence or absence of the exhaustive constraint. A selective enumeration technique is developed for solving the problem in which the code words are not equally probable and are constructed from r2 symbols. The computational feasibility of the solution technique is demonstrated. Author