of equations< by applying techniques from Galois Theory to general diagrams of forms and their solutions in terms of limits, colimits, and power objects. The papers Algebraic Varieties of Musical Performances by Roberto Ferretti and Parametric Gesture Curves: A Model for Gestural Performance by Stefan Müller deal with the mathematical description and investigation of musical performance. Ferretti’s paper applies Mazzola’s performance model and studies performances as maps from symbolic score denotators to physical ones--parametrized by suitable analytic structures and hierarchies of shaping operators (stemmata). His concern is the reversal of this production model, i.e., he calculates algebraic varieties of possible analyses and shaping operators leading to a given performance. In other words, his approach offers a mathematical metalanguage for music critique. Müller disconnects this direct link between score and performance by superimposing a gestural layer of description, which in its own comprises a symbolic and a physical level of a mediating gestural performance. He exemplifies this approach in a case study of piano playing.
Michael Leyton’s contribution Musical Works are Maximal Memory Stores offers prolegomena as well as promising ideas for the application of his generative theory of shape and especially his application of wreath products to music, involving aspects of music theory as well as music cognition.

The following four papers can be associated with the category >Mathematical Music Theory on the Object Level< and are concerned with the analysis and construction of rhythmic structures. Special interest is payed to the occurrence of a certain amount of asymmetry within these structures. Three of these papers are closely related and examplify a vivid scientific dialog. In On group-theoretical methods applied to music: some compositional and implementational aspects Moreno Andreatta recapitulates the relations between the Minkowski-Hajós problem and the study of particular rhythmic canons by Dan Todor Vuza and relates these issues to the investigation of canons by French composers. Both papers,Why Rhythmic Canons Are Interesting by Emmanuel Amiot and Tiling Problems in Music Theory by Harald Fripertinger, are devoted to a refined mathematical understanding of rhythmic canons. In continuation of Vuza’s research special attention is payed to the construction of canons which are asymmetric with respect to their inner rhythm as well as to their outer rhythm (formed by the entrances of the voices).
The joint contribution Computation of words satisfying the »Rhythmic Oddity Property« of Marc Chemillier and Charlotte Truchet is motivated by entho-musicological questions. It provides a classification of specific »odd« rhythmic patterns and associates some of these classes with occurrences in repertoires of ethnic groups.
Another group of ten papers is associated with software techniques in music theory and composition. The decision of the organizers in Zurich to include Music Informatics to the title of the seminar responded to the scientific interest of several participants to bring research activities in mathematical and in computational music theory together. The development of software tools for mathematical music theory and of formal and mathematical models for music software are the