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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

On Galois correspondences in formal logic

Yim, Austin Vincent January 2012 (has links)
This thesis examines two approaches to Galois correspondences in formal logic. A standard result of classical first-order model theory is the observation that models of L-theories with a weak form of elimination of imaginaries hold a correspondence between their substructures and automorphism groups defined on them. This work applies the resultant framework to explore the practical consequences of a model-theoretic Galois theory with respect to certain first-order L-theories. The framework is also used to motivate an examination of its underlying model-theoretic foundations. The model-theoretic Galois theory of pure fields and valued fields is compared to the algebraic Galois theory of pure and valued fields to point out differences that may hold between them. The framework of this logical Galois correspondence is also applied to the theory of pseudoexponentiation to obtain a sketch of the Galois theory of exponential fields, where the fixed substructure of the complex pseudoexponential field B is an exponential field with the field Qrab as its algebraic subfield. This work obtains a partial exponential analogue to the Kronecker-Weber theorem by describing the pure field-theoretic abelian extensions of Qrab, expanding upon work in the twelfth of Hilbert’s problems. This result is then used to determine some of the model-theoretic abelian extensions of the fixed substructure of B. This work also incorporates the principles required of this model-theoretic framework in order to develop a model theory over substructural logics which is capable of expressing this Galois correspondence. A formal semantics is developed for quantified predicate substructural logics based on algebraic models for their propositional or nonquantified fragments. This semantics is then used to develop substructural forms of standard results in classical first-order model theory. This work then uses this substructural model theory to demonstrate the Galois correspondence that substructural first-order theories can carry in certain situations.
42

Anoikonyma a mikroanoikonyma na Žďársku / Anoikonyms and microanoikonyms in the Žďársko region

Foralová, Michaela January 2013 (has links)
This thesis focuses on 375 minor place-names (hydronyms, oronyms and land names) in the region of Žďársko. The origin of 185 anoikonyms is studied from a linguistic aspect for the first time; the other names are taken from my bachelor thesis. The objective of this thesis is to determine the origin of given minor place-names. The required information was searched in various printed materials, journals and also on the Internet. As an important source for examination several local witnesses have been interviewed and consultation with experts in onomastic was conducted. Methods such as collection, analysis and interpretation of the collected data were used in this thesis. Consequently, after the origin was clarified, the anoikonyms were analyzed according to the so called model theory - it was assigned to individual relational and structural models or types. This thesis aims for systematical approach to minor place-names and their preservation for future generations.
43

Neuronové modelování matematických struktur a jejich rozšíření / Neural modelling of mathematical structures and their extensions

Smolík, Martin January 2019 (has links)
In this thesis we aim to build algebraic models in computer using machine learning methods and in particular neural networks. We start with a set of axioms that describe functions, constants and relations and use them to train neural networks approximating them. Every element is represented as a real vector, so that neural networks can operate on them. We also explore and compare different representations. The main focus in this thesis are groups. We train neural representations for cyclic (the simplest) and symmetric (the most complex) groups. Another part of this thesis are experiments with extending such trained models by introducing new "algebraic" elements, not unlike the classic extension of rational numbers Q[ √ 2]. 1
44

Éliminations dans les corps valués / Eliminations in valued fields

Rideau, Silvain 09 December 2014 (has links)
Cette thèse est une contribution à la théorie des modèles des corps valués. Les principaux résultats de ce texte sont des résultats d’éliminations des quantificateurs et des imaginaires. Le premier chapitre contient une étude des imaginaires dans les extensions finies de Qp. On y démontre que ces corps ainsi que leurs ultraproduits éliminent les imaginaires dans le langage géométrique. On en déduit un résultat de rationalité uniforme pour les fonctions zêta associées aux familles de relations d’équivalences définissables dans les extensions finies de Qp. La motivation première du deuxième chapitre est l’étude de W(F_p^alg) en tant que corps valué analytique de différence. Plus généralement, on démontre un théorème d’élimination des quantificateurs de corps dans le langage RV pour les corps valués analytiques -Henséliens de caractéristique nulle. On donne aussi une axiomatisation de la théorie de W(F_p^alg) ainsi qu’une preuve qu’elle est NIP. Dans le troisième chapitre, on prouve la densité des types définissables dans certains enrichissements d’ACVF. On en déduit un critère pour l’élimination des imaginaires et la propriété d’extension invariante. Ce chapitre contient aussi des résultats abstraits sur les ensembles extérieurement définissables dans les théories NIP. Dans le dernier chapitre, les résultats du chapitre précédent sont appliqués à VDF, la modèle complétion des corps valués munis d’une dérivation qui préserve la valuation, pour obtenir l’élimination des imaginaires dans le langage géométrique ainsi que la densité des types définissables et la propriété d’extension invariante. Ce chapitre contient aussi des considérations sur les fonctions définissables, les types et les groupes définissables dans VDF. / This thesis is about the model theory of valued fields. The main results in this text are eliminationsof quantifiers and imaginaries. The first chapter is concerned with imaginaries in finite extensions of Qp. I show that these fields and their ultraproducts eliminate imaginaries in the geometric language. As a corollary, I obtain the uniform rationality of zeta functions associated to families of equivalence relations that aredefinable in finite extensions of Qp.The motivation for the second chapter is to study W(F_p^alg) as an analytic difference valued field. More generally, I show a field quantifier elimination theorem in the RV-language for -Henselian characteristic zero valued fields with an analytic structure. I also axiomatise the theory of W(F_p^alg) and I show that this theory is NIP.In the third chapter, I prove the density of definable types in certain enrichments of ACVF. From this result, I deduce a criterion for the elimination of imaginaries and the invariant property. This chapter also contains abstract results on externally definable sets in NIP theories. In the last chapter, the previous chapter is applied to VDF, the model completion of valued fields with a valuation preserving derivation, to obtain the elimination of imaginaries in the geometric language, as well as the density of definable types and the invariant extension property. This chapter also contains considerations about definable functions, types and definable groupes in VDF.
45

Minimal walks and applications / Passeios mínimos e aplicações

Rafael de Lima Bordoni 10 August 2018 (has links)
Minimal Walks are a method of demonstrations in set theory and general topology. Although the main work of this document will be the construction of the L space, we intend to explain walk\'s fundamentals in a bit more detail. / Passeios mínimos são um método de demonstrações em teoria dos conjuntos e topologia geral. Apesar do trabalho principal dessa dissertação ser a existência do L espaço, a intenção é explicar os fundamentos dos passeios mínimos um tanto detalhadamente.
46

Propriétés combinatoires et modèle-théoriques des groupes / Combinatorial and model-theoretic properties of groups

Neman, Azadeh 07 July 2009 (has links)
Notre travail ici concerne certaines pistes pour des constructions nouveaux groupes, et en particulier de contre-exemples à la conjecture de Cherlin-Zilber. On parvient à trouver une réponse pour la stabilité de groupes CSA existentiellement clos. On exhibe un mot de groupe en deux variables qui a la propriété d’indépendance par rapport à la classe de groupes hyperboliques sans torsion. On en déduit que l’équation correspondante donne la propriété d’indépendance des groupes CSA existentiellement clos, ce qui en particulier implique leur instabilité. En outre, on prouve que les équations, et en particulier les ensembles définissables sans quantificateurs, définissent des ensembles stables dans les boules bornées des produits libres de groupes, en utilisant la version finie du théorème de Ramsey. Enfin, on introduit certains groupes construits comme tours particulières de produits libres et d’extensions HNN. / Our work here relates to certain routes for the construction of new groups, and in particular, of counter-examples to the Cherlin-Zilber conjecture. We managed to find an answer for the stability of existentially closed CSA- groups. We build a group word in two variables that has the independence property relatively to the class of torsion-free hyperbolic groups. We deduced that the corresponding equation gives the independence property of existentially closed CSA groups which in turn implies their instability. Moreover, we demonstrate that group words, and in particular quantifierfree definable sets, define stable sets in bounded balls of free products of groups using a finite version of Ramsey’s theorem. Finally, we introduce certain groups constructed as special towers of free products and HNN-extensions.
47

Model Theory of Fields and Heights / La théorie des modèles des corps et des hauteurs

Göral, Haydar 03 July 2015 (has links)
Dans cette thèse, nous traitons la théorie des modèles de corps algébriquement clos étendu par prédicats pour désigner soit des éléments de hauteur bornée, soit des sous-groupes multiplicatifs satisfaisant une condition diophantienne. Les questions que nous considérons appartiennent au domaine de la théorie de la stabilité. Tout d'abord, nous examinons un corps algébriquement clos avec un sous-groupe multiplicatif distingué qui satisfait la propriété Mann. Ainsi, nous caractérisons l'indépendance qui nous permet de caractériser les groupes définissables et les groupes interprétables dans la paire. Ensuite, nous étudions les corps algébriquement clos étendu par un sous-corps propre algébriquement clos et un sous- groupe multiplicatif. Nous caractérisons les groupes définissables et interprétables dans cette triple. Nous considérons aussi l'ensemble des nombres algébriques avec des éléments de petite hauteur et nous montrons que cette théorie n'est pas simple et a la propriété d'indépendance. Puis, nous nous rapportons à la simplicité d'une certaine paire avec la conjecture de Lehmer. Enfin, nous appliquons l'analyse non standard pour prouver l'existence de certaines bornes de hauteur de la complexité des coefficients de certains polynômes. Cela nous permet de caractériser l'appartenance idéale d'un polynôme donné. De plus, nous obtenons une borne pour la fonction de la hauteur logarithmique, ce qui nous permet de tester la primalité d'un idéal / In this thesis, we deal with the model theory of algebraically closed fields expanded by predicates to denote either elements of small height or multiplicative subgroups satisfying a Diophantine condition. The questions we consider belong to the area of stability theory. First, we investigate an algebraically closed field with a distinguished multiplicative subgroup satisfying the Mann property. We characterize the independence which enables us to characterize definable and interpretable groups in the pair. Then we study the model theory of algebraically closed fields expanded by a proper algebraically closed subfield and a multiplicative subgroup. We characterize definable and interpretable groups in this triple. We also consider the set of algebraic numbers with elements of small height and we show that this theory is not simple and has the independence property. We then relate the simplicity of a certain pair with Lehmer’s conjecture. Finally, we apply nonstandard analysis to prove the existence of certain height bounds on the complexity of the coefficients of some polynomials. This allows us to characterize the ideal membership of a given polynomial. Moreover, we obtain a bound for the logarithmic height function, which enables us to test the primality of an ideal
48

Minimal walks and applications / Passeios mínimos e aplicações

Bordoni, Rafael de Lima 10 August 2018 (has links)
Minimal Walks are a method of demonstrations in set theory and general topology. Although the main work of this document will be the construction of the L space, we intend to explain walk\'s fundamentals in a bit more detail. / Passeios mínimos são um método de demonstrações em teoria dos conjuntos e topologia geral. Apesar do trabalho principal dessa dissertação ser a existência do L espaço, a intenção é explicar os fundamentos dos passeios mínimos um tanto detalhadamente.
49

Exploring the Knowledge Sharing Intention of Business Employees with Relations Model Theory

Lu, Chun-tai 16 July 2007 (has links)
With a view to achieve the ultimate goal of a permanent development, operation, and growth, to any business and enterprise, the strategy of knowledge management must be reinforced, and the sooner the better. In despite of those new and high interests shown toward the organization-embedded knowledge, not much concrete finding has been obtained regarding how and why employees are reluctant to share what they know. In our research, we proposed to base on the Relations Model Theory to explore how different relation models, cultivated and shaped by different corporate cultures, give their influences on the willingness of knowledge sharing from employees. In the mean time, with a view to get closer to the realistic circumstance in the office, we give it a shot to include additional moderating variables, task inter-dependence, as well as time-of-cooperation, into our full research framework, aiming to see if they will disturb the influencing processes between the four principal relations and the willingness of employees to share their knowledge. The result reflects the distinct impact from communal sharing and equality matching on the willingness of sharing, while a subtle but negative impact of market pricing on the sharing willingness. There is no clear effect of authority ranking. Furthermore, in the analysis of interaction mode including additional moderators, the result has exhibited that task inter-dependence does moderate the relationship between communal sharing / equality matching / market pricing and the notion of sharing, while time-of-cooperation also adjusts the influencing processes between communal sharing, equality matching, market pricing, and willingness of sharing. This analysis and study grant us some clues regarding how corporate culture would eventually leverage employees¡¦ intention in sharing their knowledge, and advise the business organizations how they should correctly formulate the knowledge management strategy and activities to augment the knowledge inter-flows between employees.
50

Studies on DC/DC Power Supply Management Strategy - D Company as an Example

Lee, Hsuan-min 09 July 2009 (has links)
The telecommunication/IT industry were rapid growing in the recent years, and the telecommunication manufacturer promoted the foundation equipment application unceasingly. In such the developing nations like China and India, the network foundation equipment demand grows gradually, in which China was already the quickest growing nation in telecommunication markets of the whole world, the growth rate will continuously maintain about 14% every year in the future. The Switching Power Supply (hereafter refers to as SPS) is rapidly growing in the country, in which the SPS has high profit potential product. By successful developing experience, integrity, vertical & horizontal conformity industrial structure, high quality, short delivery, smaller size, higher output, lower cost, better radiation, which create the industry competitive advantages. The purpose of research is to understand the industry development tendency of SPS, and will discuss how the value chain of SPS to survive under the global finance pressure, and even face with the re-shuffle effect. In this research take D Corporation as the example, discusses under the marketing demand drop pressure , how to develop the competitive business model and key successful factors to cope with. Then, using tool like SWOT, five forces analyses, discovers the way for D corporation to go forward to right direction. Finally, the concrete suggestion will be proposed, and to provide with the conclusion to D Corporation and related Department or organization as compete strategy in the future.

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