28,964 research outputs found

    Modelling Deep Indeterminacy

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    This paper constructs a model of metaphysical indeterminacy that can accommodate a kind of ‘deep’ worldly indeterminacy that arguably arises in quantum mechanics via the Kochen-Specker theorem, and that is incompatible with prominent theories of metaphysical indeterminacy such as that in Barnes and Williams (2011). We construct a variant of Barnes and Williams's theory that avoids this problem. Our version builds on situation semantics and uses incomplete, local situations rather than possible worlds to build a model. We evaluate the resulting theory and contrast it with similar alternatives, concluding that our model successfully captures deep indeterminacy

    Quantization of the AdS3{\rm AdS}_3 Superparticle on OSP(1∣2)2/SL(2,R){\rm OSP}(1|2)^2/{\rm SL}(2,\mathbb{R})

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    We analyze AdS3{\rm AdS}_3 superparticle dynamics on the coset OSP(1∣2)×OSP(1∣2)/SL(2,R){\rm OSP}(1|2) \times {\rm OSP}(1|2)/{\rm SL}(2,\mathbb{R}). The system is quantized in canonical coordinates obtained by gauge invariant Hamiltonian reduction. The left and right Noether charges of a massive particle are parametrized by coadjoint orbits of a timelike element of osp(1∣2)\frak{osp}(1|2). Each chiral sector is described by two bosonic and two fermionic canonical coordinates corresponding to a superparticle with superpotential W=q−m/qW=q-m/q, where mm is the particle mass. Canonical quantization then provides a quantum realization of osp(1∣2)⊕osp(1∣2)\frak{osp}(1|2)\oplus\frak{osp}(1|2). For the massless particle the chiral charges lie on the coadjoint orbit of a nilpotent element of osp(1∣2)\frak{osp}(1|2) and each of them depends only on one real fermion, which demonstrates the underlying κ\kappa-symmetry. These remaining left and right fermionic variables form a canonical pair and the system is described by four bosonic and two fermionic canonical coordinates. Due to conformal invariance of the massless particle, the osp(1∣2)⊕osp(1∣2)\frak{osp}(1|2)\oplus\frak{osp} (1|2) extends to the corresponding superconformal algebra osp(2∣4)\frak{osp}(2|4). Its 19 charges are given by all real quadratic combinations of the canonical coordinates, which trivializes their quantization.Comment: 25+1 pages; v2: minor changes, references added and updated; v3: minor changes, one reference added, matches published versio

    The Curse of Knowledge in Economic Settings: An Experimental Analysis

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    In economic analyses of asymmetric information, better-informed agents are assumed capable of reproducing the judgments of less-informed agents. We discuss a systematic violation of this assumption that we call the "curse of knowledge." Better-informed agents are unable to ignore private information even when it is in their interest to do so; more information is not always better. Comparing judgments made in individual-level and market experiments, we find that market forces reduce the curse by approximately 50 percent but do not eliminate it. Implications for bargaining, strategic behavior by firms, principal-agent problems, and choice under un-certainty are discussed

    Deep Indeterminacy in Physics and Fiction

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    Indeterminacy in its various forms has been the focus of a great deal of philosophical attention in recent years. Much of this discussion has focused on the status of vague predicates such as ‘tall’, ‘bald’, and ‘heap’. It is determinately the case that a seven-foot person is tall and that a five-foot person is not tall. However, it seems difficult to pick out any determinate height at which someone becomes tall. How best to account for this phenomenon is, of course, a controversial matter. For example, some (such as Sorensen (2001) and Williamson (2002)) maintain that there is a precise height at which someone becomes tall and such apparent cases of indeterminacy merely reflects our ignorance of this fact. Others maintain that there is some genuine – and not merely epistemic – indeterminacy present is such cases and offer various accounts of how best to account for it. Supervaluationists (such as Keefe (2008)), for example, claim that the indeterminacy with respect to vague terms lies in their not having a single definite extension. Rather, each term is associated with a range of possible precise extensions or precisifications such that it is semantically unsettled which is the correct extension. One precisification of ‘tall’ might allow that anyone over five feet ten inches is tall, whereas another would only allow those over six foot to qualify; but no precisification will take someone who is five foot to be tall, and someone who is seven foot will count as tall on all precisifications. Thus – while someone who is seven foot will be determinately tall and someone who is five foot determinately not so – it will be indeterminate whether someone who stands at five foot eleven inches is tall. Yet, it is important to stress that putative cases of indeterminacy are not limited to vague predicates of this kind. Philosophers have invoked indeterminacy in discussions of topics as diverse as moral responsibility (Bernstein (forthcoming)), identity over time (Williams (2014)), and the status of the future (Barnes and Cameron (2009)). In this paper, we focus on two areas where discussion of various kinds of indeterminacy has been commonplace: physics and fiction. We propose a new model for understanding indeterminacy across these domains and argue that it has some notable advantages when compared to earlier accounts. Treating physics and fiction cases univocally also indicates an interesting connection between indeterminacy in these two areas

    A design-for-casting integrated approach based on rapid simulation and modulus criterion

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    This paper presents a new approach to the design of cast components and their associated tools. The current methodology is analysed through a case study and its main disadvantages underlined. Then, in order to overcome these identified drawbacks, a new approach is proposed. Knowing that this approach is mainly based on a rapid simulation of the process, basics of a simplified physical model of solidification are presented as well as an associated modulus criterion. Finally, technical matters for a software prototype regarding the implementation of this Rapid Simulation Approach (RSA) in a CAD environment are detailed
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