6,776 research outputs found

    Canonical extension and canonicity via DCPO presentations

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    The canonical extension of a lattice is in an essential way a two-sided completion. Domain theory, on the contrary, is primarily concerned with one-sided completeness. In this paper, we show two things. Firstly, that the canonical extension of a lattice can be given an asymmetric description in two stages: a free co-directed meet completion, followed by a completion by \emph{selected} directed joins. Secondly, we show that the general techniques for dcpo presentations of dcpo algebras used in the second stage of the construction immediately give us the well-known canonicity result for bounded lattices with operators.Comment: 17 pages. Definition 5 was revised slightly, without changing any of the result

    Duality and canonical extensions for stably compact spaces

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    We construct a canonical extension for strong proximity lattices in order to give an algebraic, point-free description of a finitary duality for stably compact spaces. In this setting not only morphisms, but also objects may have distinct pi- and sigma-extensions.Comment: 29 pages, 1 figur

    A view of canonical extension

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    This is a short survey illustrating some of the essential aspects of the theory of canonical extensions. In addition some topological results about canonical extensions of lattices with additional operations in finitely generated varieties are given. In particular, they are doubly algebraic lattices and their interval topologies agree with their double Scott topologies and make them Priestley topological algebras.Comment: 24 pages, 2 figures. Presented at the Eighth International Tbilisi Symposium on Language, Logic and Computation Bakuriani, Georgia, September 21-25 200

    Beyond corona: getting EU economic security right. Egmont European Security Brief No. 127 April 2020

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    The corona crisis, the US-China great power competition and lacklustre international rules vividly demonstrate the vulnerability of economic interdependence. Interdependence is a power struggle, not a mutual aid society. For the vast benefits of a globalised economy to continue to outweigh its risks, policies to build greater resilience are necessary. For the EU, the unprecedented events also offer an opportunity to forge a new economic security approach to better manage its dependencies in strategic sectors

    What Could a Geoeconomic EU Look Like in 2020? Egmont Security Policy Brief No. 123 February 2020

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    The need for the EU to respond and position itself in the deepening geoeconomic competition between the Great Powers has initiated a policy reorientation that is slowly attempting to break down the barriers between economic and security concerns. But how can a more geoeconomic EU ensure an integrated approach to economic, technological and security policy that allows it both to manage new risks and also retain the principles of openness and cooperation? Getting a geoeconomic EU right will require a strategy which defines and operationalises the notion of ‘European economic sovereignty’. This would support the EU and Member States in managing the increasing tension between openness and protection in prospective policy. On that basis, a geoeconomic EU in 2020 could see it reinforcing resilience to economic coercion and strengthening its role in emerging technology-security governance and diplomacy

    Assessing the efficiency of first-principles basin-hopping sampling

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    We present a systematic performance analysis of first-principles basin-hopping (BH) runs, with the target to identify all low-energy isomers of small Si and Cu clusters described within density-functional theory. As representative and widely employed move classes we focus on single-particle and collective moves, in which one or all atoms in the cluster at once are displaced in a random direction by some prescribed move distance, respectively. The analysis provides detailed insights into the bottlenecks and governing factors for the sampling efficiency, as well as simple rules-of-thumb for near-optimum move settings, that are intriguingly independent of the distinctly different chemistry of Si and Cu. At corresponding settings, the observed performance of the BH algorithm employing two simple, general-purpose move classes is already very good, and for the small systems studied essentially limited by frequent revisits to a few dominant isomers.Comment: 11 pages including 8 figures; related publications can be found at http://www.fhi-berlin.mpg.de/th/th.htm

    Coupling Performance Measurement and Collective Activity: The Semiotic Function of Management Systems. A Case Study

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    Theories about management instruments often enter dualistic debates between structure and agency: do instruments determine the forms of collective activity (CA), or do actors shape instruments to their requirements, or are instruments and concrete activity decoupled, as some trends of new institutionalist theory assume? Attempts to overcome the dualistic opposition between structure and activity stem from diverse sources: actors’ networks theory, structuration theory, pragmatism, theory of activity, semiotics. Performance measurement and management systems can be defined as structural instruments engaged in CA. As such they constrain the activity, but they do not determine it. Reciprocally, they are modified by the way CA uses them and makes sense of them. The central thesis of this paper will be that it is impossible to study the role of performance measurement as a common language in organizations independently from the design of the CA in which it is engaged. There is a not deterministic coupling between structure (i.e. management technical tools) and CA (i.e. business processes). The transformation of CA entails a transformation in the meaning of the “performance” concept, in the type of measurement required and in the performance management practices. The relationship between performance measurement and CA is studied here in the production division of a large electricity utility in France. The research extended over several years and took place when two new management systems were simultaneously implemented: a new management accounting system and an integrated management information system (ERP), both in the purchasing process. The new management accounting system was designed by the purchasing department; the new management information system was designed by the operational departments. Whereas the coherence between both projects could have been given by their common subordination to the rebuilding of CA (the purchasing process), their disconnection from concrete CA opened the possibility of serious dissonances between them. Both the new performance management system and the new ERP met difficulties to provide common languages, since the dimension of CA was taken for granted and consequently partly ignored in the engineering of both systems. When CA incurs radical transformations, actors’direct discursive exchanges about it, “collective activity about collective activity”, become necessary to ensure a flexible and not deterministic coupling between CA and new management systems. This reflexive and collective analysis of the process by actors themselves requires the establishment of “communities of process”, which can jointly redesign the CA and its performance measurement system. We conclude that performance measurement can be a common language as far as there is a clear and shared understanding of how CA should concretely take place and should be assigned to the different categories of actors.Business Process; Collective Activity; Community of Process; Management Instruments; Performance Measurement; Semiotics; Theory of Activity
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