ni~'c~'sit~j of California at Los AngeleaIn this paper are defined the basic elements of' the theory of files~ which was presented in [23].In particular, a system lgllgtlt~ge is considered, wlfich allows the use of mathematical methods for the description of procedures in which non-numerical information processing i8 of primary importance.This language is called the Algebraic Data System Language.~ The main features of the language are the following:The Algebraic Data System Language uses logieo-mathematieal techniques to control the d'~ta flow.A procedure description consists of a sequence of statements, which are not in a biunique correspondence with the boxes of any flow diagram of the machine control, in other words, the description of a procedure is asyncronous with respect to the manner in which the procedure is carried out by the machine.The schemes by which any problem is solved, and in particular the scheme of the data flow, are determined by the computer, in accordance with its internal structure and inputoutput equipment.Procedure descriptions are consequently independent of the hardware *

The preparation of this paper