2,683 research outputs found

    Introduction to Gestural Similarity in Music. An Application of Category Theory to the Orchestra

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    Mathematics, and more generally computational sciences, intervene in several aspects of music. Mathematics describes the acoustics of the sounds giving formal tools to physics, and the matter of music itself in terms of compositional structures and strategies. Mathematics can also be applied to the entire making of music, from the score to the performance, connecting compositional structures to acoustical reality of sounds. Moreover, the precise concept of gesture has a decisive role in understanding musical performance. In this paper, we apply some concepts of category theory to compare gestures of orchestral musicians, and to investigate the relationship between orchestra and conductor, as well as between listeners and conductor/orchestra. To this aim, we will introduce the concept of gestural similarity. The mathematical tools used can be applied to gesture classification, and to interdisciplinary comparisons between music and visual arts.Comment: The final version of this paper has been published by the Journal of Mathematics and Musi

    On algebraic supergroups, coadjoint orbits and their deformations

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    In this paper we study algebraic supergroups and their coadjoint orbits as affine algebraic supervarieties. We find an algebraic deformation quantization of them that can be related to the fuzzy spaces of non commutative geometry.Comment: 37 pages, AMS-LaTe

    The moduli space of matroids

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    In the first part of the paper, we clarify the connections between several algebraic objects appearing in matroid theory: both partial fields and hyperfields are fuzzy rings, fuzzy rings are tracts, and these relations are compatible with the respective matroid theories. Moreover, fuzzy rings are ordered blueprints and lie in the intersection of tracts with ordered blueprints; we call the objects of this intersection pastures. In the second part, we construct moduli spaces for matroids over pastures. We show that, for any non-empty finite set EE, the functor taking a pasture FF to the set of isomorphism classes of rank-rr FF-matroids on EE is representable by an ordered blue scheme Mat(r,E)Mat(r,E), the moduli space of rank-rr matroids on EE. In the third part, we draw conclusions on matroid theory. A classical rank-rr matroid MM on EE corresponds to a K\mathbb{K}-valued point of Mat(r,E)Mat(r,E) where K\mathbb{K} is the Krasner hyperfield. Such a point defines a residue pasture kMk_M, which we call the universal pasture of MM. We show that for every pasture FF, morphisms kMFk_M\to F are canonically in bijection with FF-matroid structures on MM. An analogous weak universal pasture kMwk_M^w classifies weak FF-matroid structures on MM. The unit group of kMwk_M^w can be canonically identified with the Tutte group of MM. We call the sub-pasture kMfk_M^f of kMwk_M^w generated by ``cross-ratios' the foundation of MM,. It parametrizes rescaling classes of weak FF-matroid structures on MM, and its unit group is coincides with the inner Tutte group of MM. We show that a matroid MM is regular if and only if its foundation is the regular partial field, and a non-regular matroid MM is binary if and only if its foundation is the field with two elements. This yields a new proof of the fact that a matroid is regular if and only if it is both binary and orientable.Comment: 83 page

    Boolean Coverings of Quantum Observable Structure: A Setting for an Abstract Differential Geometric Mechanism

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    We develop the idea of employing localization systems of Boolean coverings, associated with measurement situations, in order to comprehend structures of Quantum Observables. In this manner, Boolean domain observables constitute structure sheaves of coordinatization coefficients in the attempt to probe the Quantum world. Interpretational aspects of the proposed scheme are discussed with respect to a functorial formulation of information exchange, as well as, quantum logical considerations. Finally, the sheaf theoretical construction suggests an opearationally intuitive method to develop differential geometric concepts in the quantum regime.Comment: 25 pages, Late

    Disentangling agglomeration and network externalities : a conceptual typology

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    Agglomeration and network externalities are fuzzy concepts. When different meanings are (un)intentionally juxtaposed in analyses of the agglomeration/network externalities-menagerie, researchers may reach inaccurate conclusions about how they interlock. Both externality types can be analytically combined, but only when one adopts a coherent approach to their conceptualization and operationalization, to which end we provide a combinatorial typology. We illustrate the typology by applying a state-of-the-art bipartite network projection detailing the presence of globalized producer services firms in cities in 2012. This leads to two one-mode graphs that can be validly interpreted as topological renderings of agglomeration and network externalities

    Interactive semantic mapping: Experimental evaluation

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    Robots that are launched in the consumer market need to provide more effective human robot interaction, and, in particular, spoken language interfaces. However, in order to support the execution of high level commands as they are specified in natural language, a semantic map is required. Such a map is a representation that enables the robot to ground the commands into the actual places and objects located in the environment. In this paper, we present the experimental evaluation of a system specifically designed to build semantically rich maps, through the interaction with the user. The results of the experiments not only provide the basis for a discussion of the features of the proposed approach, but also highlight the manifold issues that arise in the evaluation of semantic mapping
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