The art of music is no longer limited to the sounding models of instruments and voices. Electoacoustic music opens access to all sounds, a bewildering sonic array ranging from the real to the surreal and beyond. For listeners the traditional links with physical sound-making are frequently ruptured: electroacoustic sound-shapes and qualities frequently do not indicate known sources and causes. Gone are the familiar articulations of instruments and vocal utterance: gone is the stability of note and interval: gone too is the reference of beat and metre. Composers also have problems: how to cut an aesthetic path and discover a stability in a wide-open sound world, how to develop appropriate sound-making methods, how to select technologies and software.

This article may be considered the outline of an ongoing study of different types of structural concepts, and their referential or non-referential content, in electroacoustic, computer and mixed music composed mostly in French electroacoustic music studios (GRM, IRCAM, UPIC, GMEM, etc.). This analytical study began in Hungary in 1988, in the course of a broadcast series on certain chapters of the history of electroacoustic music. This work has been supported in Hungary by the Soros Foundation.The study later investigated narrativity in electroacoustic music, In the form of a paper presented at the 2nd International Symposium on Musical Signification (Helsinki, 1988), published in French, in the No. 51 issue of MUSICWORKS Magazine, and in the Acts of the Symposium published in English, in 1995: ‘Narrativity and electroacoustic music’, in Musical signification, E. Tarasti, ed., Mouton de Gruyter, Berlin and New York.and then incorporated a more complex typology embracing formal, structural approaches in about thirty characteristic works composed since the 1970s. Work on these selected pieces offers a range of investigations into their structure, from the assumption of the oldest structural concepts through to very recent ideas.Plan of a book, some chapters of which were drafted in France, from 1990 onwards, thanks to a grant awarded to CIREM by the Direction de la Musique du Ministère de la Culture, with a view to publishing works on electroacoustic music.

Assuming that perception works as a constant dialectic between sense-data and concept, this paper presents a perceptual analysis of J. C. Risset‘s Sud according to a conceptual framework based on a complementarity between intrinsic and extrinsic connotations in electroacoustic music. From this perspective, Sud may be perceived as an encounter between human imagination and nature in two of its most powerful symbols: the sea, alluded to through the sounds of the waves, and the forest, alluded to through the sounds of birds and insects. The piece presents an exploration of the essence of these environmental sounds, which are either modified or recreated with different substances. In its appeal to images widespread in a variety of cultures, as well as in its unique use of traditional musical materials, Sud is more than a strongly programmatic and visually evocative piece.

For a finite set D of nodes let E2(D)={(x, y)[mid ]x, y∈D, x≠y}. We define an inversive Δ2-structure g as a function g[ratio ]E2(D)→Δ into a given group Δ satisfying the property g(x, y)=g(y, x)−1 for all (x, y)∈E2(D). For each function (selector) σ[ratio ]D→Δ there is a corresponding inversive Δ2-structure gσ defined by gσ(x, y)=σ(x)·g(x, y)·σ(y)−1. A function η mapping each g into the group Δ is called an invariant if η(gσ)=η(g) for all g and σ. We study the group of free invariants η of inversive Δ2-structures, where η is defined by a word from the free monoid with involution generated by the set E2(D). In particular, if Δ is abelian, the group of free invariants is generated by triangle words of the form (x0, x1)(x1, x2)(x2, x0).

This paper explores the relationship between how we use and theorise frequency as musicians and how frequency is perceived by listeners within the technological and ideological context of electroacoustic music. With reference to work in perception, music theory and aesthetics, it is argued that thinking about frequency is still dominated by the idea of music’s abstract significance. It is suggested that although electroacoustic music presents a challenge to such ideology, this challenge is not reflected in current musical research, leading to a peculiar dislocation between practice and theory. In conclusion, it is proposed that studying the ways in which frequency structure contributes to meaning might provide a better understanding of the production and perception of electroacoustic music than studying frequency structure in itself.

Place/transition (PT) Petri nets are one of the most widely used models of concurrency. However, they still lack, in our view, a satisfactory semantics: on the one hand the ‘token game’ is too intensional, even in its more abstract interpretations in terms of nonsequential processes and monoidal categories; on the other hand, Winskel's basic unfolding construction, which provides a coreflection between nets and finitary prime algebraic domains, works only for safe nets. In this paper we extend Winskel's result to PT nets. We start with a rather general category PTNets of PT nets, we introduce a category DecOcc of decorated (nondeterministic) occurrence nets and we define adjunctions between PTNets and DecOcc and between DecOcc and Occ, the category of occurrence nets. The role of DecOcc is to provide natural unfoldings for PT nets, i.e., acyclic safe nets where a notion of family is used to relate multiple instances of the same place. The unfolding functor from PTNets to Occ reduces to Winskel's when restricted to safe nets. Moreover, the standard coreflection between Occ and Dom, the category of finitary prime algebraic domains, when composed with the unfolding functor above, determines a chain of adjunctions between PTNets and Dom.

Pitch and loudness are subjective aspects of sound which can be described in terms of the observed abilities of subjects to rate them on a scale from ‘low’ to ‘high’. Timbre is a subjective aspect of sound for which there is no such scale and neither qualitative nor quantitative descriptions are generally found that are widely accepted. The purpose of this paper is to shed light on some frequency domain aspects of the nature of timbre by making use of the results obtained from an analysis system which is designed to take advantage of contemporary psychoacoustical knowledge relating to human peripheral hearing. Results are presented which illustrate the relationship between contemporary psychoacoustic ideas relating to timbre and ideas first discussed by Helmholtz and later taken up by other researchers. Analyses by the system of a selection of sounds from acoustic musical instruments with clear timbral differences are also presented in order to place these discussions in a musical context.

To a practising composer the term 'frequency domain' must refer primarily to the ways s/he organises pitch material. Additionally, to the experienced electroacoustic composer, it will refer to the treatment of the spectral content of sounds used, which may or may not be a conscious act within the compositional process.

We investigate Girard's calculus Fω as a ‘Curry style’ type assignment system for pure lambda terms. First we show an example of a strongly normalizable term that is untypable in Fω. Then we prove that every partial recursive function is nonuniformly represented in Fω (even if quantification is restricted to constructor variables of level 1). It follows that the type reconstruction problem is undecidable and cannot be recursively separated from normalization.