47,568 research outputs found

    Looking for Emergence in Physics

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    Despite its recent popularity, Emergence is still a field where philosophers and physicists often talk past each other. In fact, while philosophical discussions focus mostly on ontological emergence, physical theory is inherently limited to the epistemological level and the impossibility of its conclusions to provide direct evidence for ontological claims is often underestimated. Nevertheless, the emergentist philosopher’s case against reductionist theories of how the different levels of reality are related to each other can still gain from the assessment of paradigmatic examples of discontinuity between models in physics, even though their implications must be handled with care

    The pectoralis minor muscle and shoulder movement-related impairments and pain: Rationale, assessment and management

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    The adaptive shortening or tightness of the pectoralis minor muscle (PMm) is one of the potential biomechanical mechanisms associated with altered scapular alignment at rest and scapular motion during arm elevation (scapular dyskinesis) in patients with shoulder complaints. This masterclass briefly reviews the role of the PMm in shoulder movement-related impairments and provides a critical overview of the assessment of PMm tightness and the conventional approaches to increase its resting length and extensibility. A rehabilitation approach focused on PMm stretching and simultaneous optimization of the kinematic chain of arm elevation is also discussed, hoping to improve the management of shoulder movement-related impairments and pain.info:eu-repo/semantics/publishedVersio

    Mixed Hodge structures and formality of symmetric monoidal functors

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    We use mixed Hodge theory to show that the functor of singular chains with rational coefficients is formal as a lax symmetric monoidal functor, when restricted to complex schemes whose weight filtration in cohomology satisfies a certain purity property. This has direct applications to the formality of operads or, more generally, of algebraic structures encoded by a colored operad. We also prove a dual statement, with applications to formality in the context of rational homotopy theory. In the general case of complex schemes with non-pure weight filtration, we relate the singular chains functor to a functor defined via the first term of the weight spectral sequence.Comment: 26 page

    Random Matching in the College Admissions Problem

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    In the college admissions problem, we consider the incentives confronting agents who face the prospect of being matched by a random stable mechanism. We provide a fairly complete characterization of ordinal equilbria. Namely, every ordinal equilib- rium yields a degenerate probability distribution. Furthermore, individual rationality is a necessary and sufficient condition for an equilibrium outcome, while stability is guaranteed in ordinal equilibrium where firms act straightforwardly. Finally, we re- late equilibrium behavior in random and in deterministic mechanisms.Matching; College Admissions Problem; Stability; Random Mechanism.
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