Page  292 ï~~CONSTRAINT BASED LOGIC PROGRA POLYPHONIES. Francis COURTOT, IRCAM, Department of Musical Research, 31 rue Saint-Merri, 75004 Paris, France. e-mail: courtot@ircam.fr, uunet! ircam!courtot. ABSTRACT: This paper describes a program writt development at IRCAM. The primary goal of this p which tries represent the way composer strt confronted with a computer aided composition envirc provide a computer aided composition environment composer currently working on commis Intercontemporain. FORMAL BASIS. a R 1 - W W - L F--_______ - i The program is organised according to three level order of complexity: types, methods, and concepts. We first with an example taken from P S Hurelts application. Types. The first level of representation concerns what a con "interesting objects". For representing such objects, the fu include user defined or pre-defined types like pitches, chords

Page  293 ï~~fourth category methods include graphic editors and miscellaneous methods, such as some routines, that allow th 1.3 Concepts. The third level of representation actually makes the lir refer to this level as a conceptual level, because it is seen as The user can define a set of characteristics (here called a coi object from different perspectives. These characteristics are composer has to establish the constraints. These constraints piece he is working on. In our representation, a concept i characteristics, that is a structure that states the relationsi depending on the level of formalisation the composer deals program, such as the networks used by P 0 Hurel (see below) 1.4 An example. For P. Hurel, the theory lies in a recursive structure of, b c de b fd form such apattern. When repeated 5 times, the represented in upper case) reappears every 5 symbols: A b c BcdebFd -a b c D e b f d. Figurel shows a part ofthe's greatest element has not been represented. polyphony ye voices chords melody m "-5 mnn vG

Page  294 ï~~Contr61e Fen tres Predicats NEW p a Figure 3. Each box represents a predicate, chosen in the menu Pre classified according to the categories we have mentionned al the box, a window displaying commentaries is shown, stai meaning of every argument. The little boxes within a pred white or black, they have a value or not. The connections represents equality constraints, that is disable such constraints: simply click in an argument box an verification that prohibits uncorrect unification. In order to give a value to any argument, the user graphic a a"a" - - "! T""