IA Scholar Query: A Characterisation of Meet and Join Respecting Pre-Orders and Congruences on Finite Lattices.
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Internet Archive Scholar query results feedeninfo@archive.orgThu, 15 Sep 2022 00:00:00 GMTfatcat-scholarhttps://scholar.archive.org/help1440A Low Dishonest Decade....Smart Acquisition and Defence Procurement into the New Millennium
https://scholar.archive.org/work/26yamuyhbzabvhdp7todjzpkrm
Smart acquisition was the change programme introduced at the end of the twentieth century charged with transforming the effectiveness of defence procurement within the United Kingdom. The initiative was rolled-out as a cornerstone of the Blair government's strategic defence initiative from 1998 onwards and represents, today, the management philosophy, public sector organisational structures and UK industrial strategy for delivering defence equipment. This research seeks to understand the manner and extent of changes to defence procurement derived from the smart acquisition initiative, viewed as a 'technology' through which government exercises power. Accordingly, understanding smart acquisition develops and deepens our knowledge of the nature of government itself. I offer, initially, in chapters 1 and 2 an introduction to smart acquisition, its background and historical antecedence. I discuss the methodology employed for interrogating the phenomenon as an auto/ethnographical study of UK defence practices. Chapter 3 details the factors that drove defence reorganisation, whilst chapter 4 derives smart acquisition as rational and benign managerial change. Chapter 5 critiques this perspective by unveiling smart acquisition as a neoliberal construct through which government procures and cements assemblages of regimes of control and socialisation, legitimised through managerial narratives and governmentalist forms. A revised critical analytical model of smart acquisition embracing governmentalist notions is, consequently, provided in chapter 6. Chapter 7 introduces a specific defence procurement project team and describes its transformation strategy and emerging business model. In chapter 8 the project team is superficially revealed as a rational change agent embedding and embracing management reform. Chapter 9 critiques this, presenting the team as a constructed governmentalist regime, an expression of control, socialisation and surrender of agency. Chapter 10 concludes the research by observing that smart acquisition [...]John Louthwork_26yamuyhbzabvhdp7todjzpkrmThu, 15 Sep 2022 00:00:00 GMTIntuitionistic Logic is a Connexive Logic
https://scholar.archive.org/work/to5iivjeizbqdedriqxvue6ofq
We show that intuitionistic logic is deductively equivalent to Connexive Heyting Logic (CHL), hereby introduced as an example of a strong connexive logic with intuitive semantics. We use the reverse algebraisation paradigm: CHL is presented as the assertional logic of a point regular variety (whose structure theory is examined in detail) that turns out to be term equivalent to the variety of Heyting algebras. We provide Hilbert-style and Gentzen-style proof systems for CHL; moreover, we suggest a possible computational interpretation of its connexive conditional, and we revisit Kapsner's idea of superconnexivity.Davide Fazio, Antonio Ledda, Francesco Paoliwork_to5iivjeizbqdedriqxvue6ofqWed, 31 Aug 2022 00:00:00 GMTTopological duality for distributive lattices, and applications
https://scholar.archive.org/work/xnnm6lpovzeg7euoh4xupsxexm
This material will be published by Cambridge University Press as "Topological Duality for Distributive Lattices: Theory and Applications" by Mai Gehrke and Sam van Gool. This pre-publication is free to view and download for personal use only. Not for re-distribution, re-sale, or use in derivative works. \copyright Mai Gehrke and Sam van Gool This book is a course in Stone-Priestley duality theory, with applications to logic and theoretical computer science. Our target audience are graduate students and researchers in mathematics and computer science. Our aim is to get in a fairly full palette of duality tools as directly and quickly as possible, then to illustrate and further elaborate these tools within the setting of three emblematic applications: semantics of propositional logics, domain theory in logical form, and the theory of profinite monoids for the study of regular languages and automata. This pre-publication contains the first part of the book, a graduate level 'crash course' in duality theory as it is practiced now, and a chapter on applications to domain theory.Mai Gehrke, Sam van Goolwork_xnnm6lpovzeg7euoh4xupsxexmFri, 26 Aug 2022 00:00:00 GMTMoss' logic for ordered coalgebras
https://scholar.archive.org/work/424byatauvagzo7pjd3zjkv2pi
We present a finitary version of Moss' coalgebraic logic for T-coalgebras, where T is a locally monotone endofunctor of the category of posets and monotone maps. The logic uses a single cover modality whose arity is given by the least finitary subfunctor of the dual of the coalgebra functor T_ω^∂, and the semantics of the modality is given by relation lifting. For the semantics to work, T is required to preserve exact squares. For the finitary setting to work, T_ω^∂ is required to preserve finite intersections. We develop a notion of a base for subobjects of T_ω X. This in particular allows us to talk about the finite poset of subformulas for a given formula. The notion of a base is introduced generally for a category equipped with a suitable factorisation system. We prove that the resulting logic has the Hennessy-Milner property for the notion of similarity based on the notion of relation lifting. We define a sequent proof system for the logic, and prove its completeness.Marta Bílková, Matěj Dostálwork_424byatauvagzo7pjd3zjkv2piSat, 06 Aug 2022 00:00:00 GMTRegular Categories and Soft Sheaf Representations
https://scholar.archive.org/work/lpicpw6lsff7lmvgcl5up6xw24
It has long been known that a key ingredient for a sheaf representation of a universal algebra A consists in a distributive lattice of commuting congruences on A. The sheaf representations of universal algebras (over stably compact spaces) that arise in this manner have been recently characterised by Gehrke and van Gool (J. Pure Appl. Algebra, 2018), who identified the central role of the notion of softness. In this paper, we extend the scope of this theory by replacing varieties of algebras with regular categories, thus encompassing a number of "non-algebraic" examples. Our approach is based on the notion of K-sheaf: intuitively, whereas sheaves are defined on open subsets, K-sheaves are defined on compact ones. Throughout, we consider sheaves on complete lattices rather than spaces; this allows us to obtain point-free versions of sheaf representations whereby spaces are replaced with frames. These results are used to construct sheaf representations for the dual of the category of compact ordered spaces, and to recover Banaschewski and Vermeulen's point-free sheaf representation of commutative Gelfand rings (Quaest. Math., 2011).Marco Abbadini, Luca Reggiowork_lpicpw6lsff7lmvgcl5up6xw24Fri, 29 Jul 2022 00:00:00 GMTHennessy-Milner Theorems via Galois Connections
https://scholar.archive.org/work/u4exkwmig5c2rlgvkachn7c6ci
We introduce a general and compositional, yet simple, framework that allows us to derive soundness and expressiveness results for modal logics characterizing behavioural equivalences or metrics (also known as Hennessy-Milner theorems). It is based on Galois connections between sets of (real-valued) predicates on the one hand and equivalence relations/metrics on the other hand and covers a part of the linear-time-branching-time spectrum, both for the qualitative case (behavioural equivalences) and the quantitative case (behavioural metrics). We derive behaviour functions from a given logic and give a condition, called compatibility, that characterizes under which conditions a logically induced equivalence/metric is induced by a fixpoint equation. In particular this framework allows us to derive a new fixpoint characterization of directed trace metrics.Harsh Beohar and Sebastian Gurke and Barbara König and Karla Messingwork_u4exkwmig5c2rlgvkachn7c6ciWed, 20 Jul 2022 00:00:00 GMTAlgebraic coherent confluence and higher globular Kleene algebras
https://scholar.archive.org/work/koh4cvnwdvb4bajkvcyomqtcaa
We extend the formalisation of confluence results in Kleene algebras to a formalisation of coherent confluence proofs. For this, we introduce the structure of higher globular Kleene algebra, a higher-dimensional generalisation of modal and concurrent Kleene algebra. We calculate a coherent Church-Rosser theorem and a coherent Newman's lemma in higher Kleene algebras by equational reasoning. We instantiate these results in the context of higher rewriting systems modelled by polygraphs.Cameron Calk, Eric Goubault, Philippe Malbos, Georg Struthwork_koh4cvnwdvb4bajkvcyomqtcaaTue, 19 Jul 2022 00:00:00 GMTModels of Relevant Arithmetic
https://scholar.archive.org/work/42ycsuzprvaghdsrw55i6y4emm
It is well known that the relevant arithmetic R# admits finite models whose domains are the integers modulo n rather than the expected natural numbers. Less well appreciated is the fact that the logic of these models is much more subtle than that of the three-valued structure in which they are usually presented. In this paper we consider the DeMorgan monoids in which R# can be modelled, deriving a fairly complete account of those modelling the stronger arithmetic RM# modulo n and a partial account for the case of R# modulo a prime number. The more general case in which the modulus is arbitrary is shown to lead to infinite propositional structures even with the additional constraint that '0=1' implies everything.John Slaneywork_42ycsuzprvaghdsrw55i6y4emmSun, 17 Apr 2022 00:00:00 GMTAn Introduction to Geometric Topology
https://scholar.archive.org/work/qfzo4ukjbnet7jrl7kdvouasmm
This book provides a self-contained introduction to the topology and geometry of surfaces and three-manifolds. The main goal is to describe Thurston's geometrisation of three-manifolds, proved by Perelman in 2002. The book is divided into three parts: the first is devoted to hyperbolic geometry, the second to surfaces, and the third to three-manifolds. It contains complete proofs of Mostow's rigidity, the thick-thin decomposition, Thurston's classification of the diffeomorphisms of surfaces (via Bonahon's geodesic currents), the prime and JSJ decomposition, the topological and geometric classification of Seifert manifolds, and Thurston's hyperbolic Dehn filling Theorem.Bruno Martelliwork_qfzo4ukjbnet7jrl7kdvouasmmTue, 05 Apr 2022 00:00:00 GMTSheaf representation of monoidal categories
https://scholar.archive.org/work/f2tjzphfbjgolm4lsj2vpy5rsy
Every small monoidal category with universal finite joins of central idempotents is monoidally equivalent to the category of global sections of a sheaf of local monoidal categories on a topological space. Every small stiff monoidal category monoidally embeds into such a category of global sections. An infinitary version of these theorems also holds in the spatial case. These representation results are functorial and subsume the Lambek-Moerdijk-Awodey sheaf representation for toposes, the Stone representation of Boolean algebras, and the Takahashi representation of Hilbert modules as continuous fields of Hilbert spaces. Many properties of a monoidal category carry over to the stalks of its sheaf, including having a trace, having exponential objects, having dual objects, having limits of some shape, and the central idempotents forming a Boolean algebra.Rui Soares Barbosa, Chris Heunenwork_f2tjzphfbjgolm4lsj2vpy5rsyFri, 25 Mar 2022 00:00:00 GMTStone duality for spectral sheaves and the patch monad
https://scholar.archive.org/work/mcf6irusmzhrzdjuiwxzal5uqi
We establish a duality between global sheaves on spectral spaces and right distributive bands. This is a sheaf-theoretical extension of classical Stone duality between spectral spaces and bounded distributive lattices. The topology of a spectral space admits a refinement, the so-called patch topology, giving rise to a patch monad on sheaves over a fixed spectral space. Under the duality just mentioned the algebras of this patch monad are shown to correspond to distributive skew lattices.Clemens Berger, Mai Gehrkework_mcf6irusmzhrzdjuiwxzal5uqiMon, 31 Jan 2022 00:00:00 GMTCongruence frames of frames and κ-frames
https://scholar.archive.org/work/nlpv4tzw6vgozpvu437hkltiz4
We describe the congruence lattices of frames and κ-frames. We look at the role that congruence biframes play in the category of strictly zero-dimensional biframes and discuss some reflections and coreflections of congruence frames.Graham Manuellwork_nlpv4tzw6vgozpvu437hkltiz4Sat, 15 Jan 2022 00:00:00 GMTHolistic fuel cycle modelling of a future fusion reactor = Holistische Modellierung des Brennstoffkreislaufs eines zukünftigen Fusionsreaktors
https://scholar.archive.org/work/2e3ve3o4vjbd7pzwt5vgmsfx6y
Die Gewinnung elektrischer Energie mittels magnetisch eingeschlossener Fusion stellt eine noch unerschlossene Quelle dar, dessen Verwirklichung derzeit weltweit vorangetrieben wird. Diese Arbeit beschreibt einen essenziellen Bestandteil der Infrastruktur eines solchen Kraftwerkes in einer umfassenden Simulation: den Brennstoffkreislauf. Dabei handelt es sich um eine komplexe chemische Anlage, die im Wesentlichen die Wasserstoffisotope Deuterium und Tritium als Edukte zur Fusion bereitstellt. Um die Konzentration des Fusionsprodukts Helium im Reaktor zu begrenzen, ist der Durchsatz des Brennstoffgemischs wesentlich höher als die Reaktionrate der Fusion selbst. Infolgedessen stellt unverbrannter Wasserstoff den überwiegenden Teil der Prozessgases am Reaktorausgang dar. Der Brennstoffkreislauf muss sicherstellen, dass dieser Wasserstoff mit hoher Effizienz aus dem Abgasstrom zurückgewonnen und wiederverwertet werden kann. Dafür muss das Prozessgas erst mittels Vakuumpumpen aus dem Reaktor gesaugt werden. Anschließend wird der Wasserstoff über verschiedene Trennprozesse aus dem Abgasgemisch gefiltert. Schließlich wird das Wasserstoffgemisch dem Reaktor wieder zugeführt. Im Detail werden in dieser Arbeit zuerst die Funktion und der Aufbau des Inneren Brennstoffkreislaufes für das Demonstrationskraftwerk DEMO aus dessen Randbedingungen hergeleitet. Danach werden die relevanten physikalischen Zusammenhänge der verwendeten Technologien beschrieben und als eigenständige Modelle in das Simulationsprogramm integriert. Besonderer Fokus liegt dabei auf den physikalischen Wechselwirkungen von Wasserstoff mit sich selbst, Flüssigkeiten wie Wasser sowie verschiedenen Metallen, die die Grundlage der verwendeten Trennprozesse bilden. Zur Einbindung aller Subsysteme bildet das Simulationsprogramm den kompletten Kreislauf transient in der kommerziellen Software ASPEN® Custom Modeler ab. So können das Verhalten am Betriebspunkt, während des Anfahrprozesses und für veränderliche Randbedingungen abgebildet werden. Insbesondere die Verw [...]Yannick Nicolas Hörstensmeyer, Robert Stieglitz, Rudolf Neuwork_2e3ve3o4vjbd7pzwt5vgmsfx6yAlgebraic logoi
https://scholar.archive.org/work/5man72wzobbjheiszsmns4j7b4
We introduce normal cores, as well as the more general action cores and split extension cores, in the context of a semi-abelian category. We prove that, if the category is moreover well-powered with (small) joins, then the existence of action cores is equivalent to the condition that the change-of-base functors in the fibration of points are geometric. We call a finitely complete category that satisfies this condition an algebraic logos. We give examples of such categories, compare them with algebraically coherent ones, and study equivalent conditions as well as stability under common categorical operations.D. Bourn, A. S. Cigoli, J. R. A. Gray, T. Van der Lindenwork_5man72wzobbjheiszsmns4j7b4Thu, 16 Dec 2021 00:00:00 GMTTeaP 2021 - Abstracts of the 63rd Conference of Experimental Psychologists
https://scholar.archive.org/work/m4jzvq67yzbq7dcc5oyclq2xhq
Contains Keynote Lectures, Contributions and Author Index of the 63rd Conference of Experimental Psychologists(:Unkn) Unknown, Leibniz Institut Für Psychologie (ZPID), Anke Huckauf, Martin Baumann, Marc Ernst, Cornelia Herbert, Markus Kiefer, Marian Sauterwork_m4jzvq67yzbq7dcc5oyclq2xhqWed, 27 Oct 2021 00:00:00 GMTThe local-global property for G-invariant terms
https://scholar.archive.org/work/m22aeixe3jh4bd724lr2ezqsga
For some Maltsev conditions Σ it is enough to check if a finite algebra 𝐀 satisfies Σ locally on subsets of bounded size, in order to decide, whether 𝐀 satisfies Σ (globally). This local-global property is the main known source of tractability results for deciding Maltsev conditions. In this paper we investigate the local-global property for the existence of a G-term, i.e. an n-ary term that is invariant under permuting its variables according to a permutation group G ≤ Sym(n). Our results imply in particular that all cyclic loop conditions (in the sense of Bodirsky, Starke, and Vucaj) have the local-global property (and thus can be decided in polynomial time), while symmetric terms of arity n>2 fail to have it.Alexandr Kazda, Michael Kompatscherwork_m22aeixe3jh4bd724lr2ezqsgaThu, 21 Oct 2021 00:00:00 GMT