6,776 research outputs found
Canonical extension and canonicity via DCPO presentations
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
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
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
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
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
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
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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