21,167 research outputs found

    A localic theory of lower and upper integrals

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    An account of lower and upper integration is given. It is constructive in the sense of geometric logic. If the integrand takes its values in the non-negative lower reals, then its lower integral with respect to a valuation is a lower real. If the integrand takes its values in the non-negative upper reals,then its upper integral with respect to a covaluation and with domain of integration bounded by a compact subspace is an upper real. Spaces of valuations and of covaluations are defined. Riemann and Choquet integrals can be calculated in terms of these lower and upper integrals

    Developing an independent anti-racist model for asylum rights organizing in England

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    Since the mid 1990s third sector professionals and organizations have come under increasing pressure to help enforce restrictive and punitive policies toward refugees and asylum seekers. This paper presents one response, using an empirical case study to develop an ‘Independent Anti-Racist Model’ for asylum rights organising. This combines data from a three-year study comparing four organizations in a major city in England and reflections on the author’s experience as a member of the case study organization, contextualized in the literature. The paper identifies a related set of features distinguishing this model from other types of organization and the conditions making it possible and concludes that it offers wider lessons for work with groups in a conflictual relationship with the state

    Inflation targeting in practice: the UK experience

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    In this speech (given at the CFSresearch conference on the Implementation of Price Stability held at the Bundesbank Frankfurt am Main, 10. - 12. Sept 1998), John Vickers discusses theoretical and practical issues relating to inflation targeting as used in the United Kingdom doing the past six years. After outlining the role of the Bank s Monetary Policy Committee, he considers the Committee s task from a theoretical perspective, beforediscussing the concept and measurement of domestically generated inflation

    Book review: what Ed can learn from Labour’s history on the world stage, from student revolts of the 1960s, to courting the media in the 1990s

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    The legacy of Blair and the invasions of Iraq and Afghanistan continue to loom large for the Labour Party, whether in opposition or in government, giving rise to fierce debates over Labour’s attitude towards the wider world. This book considers the idea of Labour’s international identity, examining how world events and Labour’s response to them have helped to shape ideology, political culture and domestic agendas from the 1920s until the Iraq War

    Entailment systems for stably locally compact locales

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    The category SCFrU of stably continuous frames and preframe ho-momorphisms (preserving ¯nite meets and directed joins) is dual to the Karoubi envelope of a category Ent whose objects are sets and whose morphisms X ! Y are upper closed relations between the ¯nite powersets FX and FY . Composition of these morphisms is the \cut composition" of Jung et al. that interfaces disjunction in the codomains with conjunctions in the domains, and thereby relates to their multi-lingual sequent calculus. Thus stably locally compact locales are represented by \entailment systems" (X; `) in which `, a generalization of entailment relations,is idempotent for cut composition. Some constructions on stably locally compact locales are represented in terms of entailment systems: products, duality and powerlocales. Relational converse provides Ent with an involution, and this gives a simple treatment of the duality of stably locally compact locales. If A and B are stably continuous frames, then the internal preframe hom A t B is isomorphic to e A ­ B where e A is the Hofmann-Lawson dual. For a stably locally compact locale X, the lower powerlocale of X is shown to be the dual of the upper powerlocale of the dual of X

    Ars Informatica -- Ars Electronica: Improving Sonification Aesthetics

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    In this paper we discuss æsthetic issues of sonifications. We posit that many sonifications have suffered from poor acoustic ecology which makes listening more difficult, thereby resulting in poorer data extraction and inference on the part of the listener. Lessons are drawn from the electro acoustic music community as we argue that it is not instructive to distinguish between sonifications and music/sound art. Edgar Var`ese defined music as organised sound and sonifications organise sound to reflect some aspect of the thing being sonified. Therefore, we propose that sonification designers can improve the communicative ability of their auditory displays by paying attention to the æsthetic issues that are well known to composers, orchestrators, sound designers & artists, and recording engineers

    Computable decision making on the reals and other spaces via partiality and nondeterminism

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    Though many safety-critical software systems use floating point to represent real-world input and output, programmers usually have idealized versions in mind that compute with real numbers. Significant deviations from the ideal can cause errors and jeopardize safety. Some programming systems implement exact real arithmetic, which resolves this matter but complicates others, such as decision making. In these systems, it is impossible to compute (total and deterministic) discrete decisions based on connected spaces such as R\mathbb{R}. We present programming-language semantics based on constructive topology with variants allowing nondeterminism and/or partiality. Either nondeterminism or partiality suffices to allow computable decision making on connected spaces such as R\mathbb{R}. We then introduce pattern matching on spaces, a language construct for creating programs on spaces, generalizing pattern matching in functional programming, where patterns need not represent decidable predicates and also may overlap or be inexhaustive, giving rise to nondeterminism or partiality, respectively. Nondeterminism and/or partiality also yield formal logics for constructing approximate decision procedures. We implemented these constructs in the Marshall language for exact real arithmetic.Comment: This is an extended version of a paper due to appear in the proceedings of the ACM/IEEE Symposium on Logic in Computer Science (LICS) in July 201
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