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Dissertations / Theses on the topic 'Toric algebra'
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1
Solus, Liam. "Normal and Δ-Normal Configurations in Toric Algebra." Oberlin College Honors Theses / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=oberlin1308243895.
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Petrovic, Sonja. "ALGEBRAIC AND COMBINATORIAL PROPERTIES OF CERTAIN TORIC IDEALS IN THEORY AND APPLICATIONS." UKnowledge, 2008. http://uknowledge.uky.edu/gradschool_diss/606.
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This work focuses on commutative algebra, its combinatorial and computational aspects, and its interactions with statistics. The main objects of interest are projective varieties in Pn, algebraic properties of their coordinate rings, and the combinatorial invariants, such as Hilbert series and Gröbner fans, of their defining ideals. Specifically, the ideals in this work are all toric ideals, and they come in three flavors: they are defining ideals of a family of classical varieties called rational normal scrolls, cut ideals that can be associated to a graph, and phylogenetic ideals arising in a new and increasingly popular area of algebraic statistics.
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Runge, Piotr. "A Comparison Theorem for the Topological and Algebraic Classification of Quaternionic Toric 8-Manifolds." DigitalCommons@USU, 2009. https://digitalcommons.usu.edu/etd/501.
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In order to discuss topological properties of quaternionic toric 8-manifolds, we introduce the notion of an algebraic morphism in the category of toric spaces. We show that the classification of quaternionic toric 8-manifolds with respect to an algebraic isomorphism is finer than the oriented topological classification. We construct infinite families of quaternionic toric 8-manifolds in the same oriented homeomorphism type but algebraically distinct. To prove that the elements within each family are of the same oriented homeomorphism type, and that we have representatives of all such types of a quaternionic toric 8-manifold, we present and use a method of evaluating the first Pontrjagin class for an arbitrary quaternionic toric 8-manifold.
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Agosti, Claudia. "Cohomology of hyperplane and toric arrangements." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/19510/.
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L'algebra di coomologia del complementare di un arrangiamento torico è più complicata di quella del complementare di un arrangiamento di iperpiani, in quanto il toro complesso ha già di per sè una coomologia non banale e perchè l'intersezione di due sottotori in generale non è connessa. Nel 2005, De Concini e Procesi si sono concentrati sullo studio dell'algebra di coomologia del complementare degli arrangiamenti torici nel quale le intersezioni di sottotori sono sempre connesse (arrangiamenti torici unimodulari) ottenendone una presentazione sullo stile di quella data da Orlik e Solomon per gli arrangiamenti di iperpiani. Nel 2018, Callegaro, D'Adderio, Delucchi, Migliorini e Pagaria hanno generalizzato il lavoro di De Concini e Procesi fornendo una presentazione, sempre sullo stile di quella data da Orlik e Solomon, dell'algebra di coomologia di un generico arrangiamento torico. In questa tesi descriviamo tali presentazioni dell'algebra di coomologia, soffermandoci in particolare su alcuni esempi.
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Lienkaemper, Caitlin. "Toric Ideals, Polytopes, and Convex Neural Codes." Scholarship @ Claremont, 2017. http://scholarship.claremont.edu/hmc_theses/106.
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How does the brain encode the spatial structure of the external world?
A partial answer comes through place cells, hippocampal neurons which
become associated to approximately convex regions of the world known
as their place fields. When an organism is in the place field of some place
cell, that cell will fire at an increased rate. A neural code describes the set
of firing patterns observed in a set of neurons in terms of which subsets
fire together and which do not. If the neurons the code describes are place
cells, then the neural code gives some information about the relationships
between the place fields–for instance, two place fields intersect if and only if
their associated place cells fire together. Since place fields are convex, we are
interested in determining which neural codes can be realized with convex
sets and in finding convex sets which generate a given neural code when
taken as place fields. To this end, we study algebraic invariants associated
to neural codes, such as neural ideals and toric ideals. We work with a
special class of convex codes, known as inductively pierced codes, and seek
to identify these codes through the Gröbner bases of their toric ideals.
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Lin, Matthew. "Graph Cohomology." Scholarship @ Claremont, 2016. https://scholarship.claremont.edu/hmc_theses/82.
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What is the cohomology of a graph? Cohomology is a topological invariant and encodes such information as genus and euler characteristic. Graphs are combinatorial objects which may not a priori admit a natural and isomorphism invariant cohomology ring. In this project, given any finite graph G, we constructively define a cohomology ring H*(G) of G. Our method uses graph associahedra and toric varieties. Given a graph, there is a canonically associated convex polytope, called the graph associahedron, constructed from G. In turn, a convex polytope uniquely determines a toric variety. We synthesize these results, and describe the cohomology of the associated variety directly in terms of the graph G itself.
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French, Josephine. "Toric chiral algebras." Thesis, University of Oxford, 2017. https://ora.ox.ac.uk/objects/uuid:e16ac71b-7634-48e4-971e-cda490c95f07.
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In this thesis, we investigate lattice chiral algebras as defined by Beilinson and Drinfeld. Given a factorisation monoid satisfying specific conditions and a super extension of this, Beilinson and Drinfeld show that one can push forward this line bundle (super extension) to give a factorisation algebra. Specifically, they describe this in the case of the factorisation monoid formed by taking Г-valued divisors set-theoretically supported over each divisor, for Г a lattice, as a method of constructing these lattice chiral algebras. In this work, we show that their definitions of such divisors, and of line bundles with factorisation on these, generalise to a wider class of objects given by taking coefficients in any cone, C, in a lattice. We show that, in this more general case, the functors of C-valued divisors with settheoretic pullback contained in S are ind-schemes, and, from this, that they form a factorisation monoid. Further, we show that super line bundles with factorisation exist on this factorisation monoid, and that if we have a super line bundle with factorisation on the factorisation monoid of C-valued divisors, we can push forward such a line bundle to get a chiral (factorisation) algebra as for lattices. Hence, we obtain a new class of chiral algebras via this procedure, which we call toric chiral algebras.
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Prabhu-Naik, Nathan. "Tilting bundles and toric Fano varieties." Thesis, University of Bath, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.690721.
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This thesis constructs tilting bundles obtained from full strong exceptional collections of line bundles on all smooth toric Fano fourfolds. The tilting bundles lead to a large class of explicit Calabi-Yau-5 algebras, obtained as the corresponding rolled-up helix algebra. We provide two different methods to show that a collection of line bundles is full, whilst the strong exceptional condition is checked using the package QuiversToricVarieties for the computer algebra system Macaulay2, written by the author. A database of the full strong exceptional collections can also be found in this package.
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Alexander, Nicholas Charles. "Algebraic Tori in Cryptography." Thesis, University of Waterloo, 2005. http://hdl.handle.net/10012/1154.
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Communicating bits over a network is expensive. Therefore, cryptosystems that transmit as little data as possible are valuable. This thesis studies several cryptosystems that require significantly less bandwidth than conventional analogues. The systems we study, called torus-based cryptosystems, were analyzed by Karl Rubin and Alice Silverberg in 2003 [RS03]. They interpreted the XTR [LV00] and LUC [SL93] cryptosystems in terms of quotients of algebraic tori and birational parameterizations, and they also presented CEILIDH, a new torus-based cryptosystem. This thesis introduces the geometry of algebraic tori, uses it to explain the XTR, LUC, and CEILIDH cryptosystems, and presents torus-based extensions of van Dijk, Woodruff, et al. [vDW04, vDGP+05] that require even less bandwidth. In addition, a new algorithm of Granger and Vercauteren [GV05] that attacks the security of torus-based cryptosystems is presented. Finally, we list some open research problems.
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Bouchat, Rachelle R. "ALGEBRAIC PROPERTIES OF EDGE IDEALS." UKnowledge, 2008. http://uknowledge.uky.edu/gradschool_diss/618.
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Given a simple graph G, the corresponding edge ideal IG is the ideal generated by the edges of G. In 2007, Ha and Van Tuyl demonstrated an inductive procedure to construct the minimal free resolution of certain classes of edge ideals. We will provide a simplified proof of this inductive method for the class of trees. Furthermore, we will provide a comprehensive description of the finely graded Betti numbers occurring in the minimal free resolution of the edge ideal of a tree. For specific subclasses of trees, we will generate more precise information including explicit formulas for the projective dimensions of the quotient rings of the edge ideals. In the second half of this thesis, we will consider the class of simple bipartite graphs known as Ferrers graphs. In particular, we will study a class of monomial ideals that arise as initial ideals of the defining ideals of the toric rings associated to Ferrers graphs. The toric rings were studied by Corso and Nagel in 2007, and by studying the initial ideals of the defining ideals of the toric rings we are able to show that in certain cases the toric rings of Ferrers graphs are level.
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Vasireddy, Jhansi Lakshmi. "Applications of Linear Algebra to Information Retrieval." Digital Archive @ GSU, 2009. http://digitalarchive.gsu.edu/math_theses/71.
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Some of the theory of nonnegative matrices is first presented. The Perron-Frobenius theorem is highlighted. Some of the important linear algebraic methods of information retrieval are surveyed. Latent Semantic Indexing (LSI), which uses the singular value de-composition is discussed. The Hyper-Text Induced Topic Search (HITS) algorithm is next considered; here the power method for finding dominant eigenvectors is employed. Through the use of a theorem by Sinkohrn and Knopp, a modified HITS method is developed. Lastly, the PageRank algorithm is discussed. Numerical examples and MATLAB programs are also provided.
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Mahanta, Snigdhayan. "Algebraic aspects of noncommutative tori: the Riemann-Hilbert correspondence." [S.l.] : [s.n.], 2007. http://deposit.ddb.de/cgi-bin/dokserv?idn=985411716.
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Bossinger, Lara [Verfasser], and Peter [Gutachter] Littelmann. "Toric degenerations: a bridge between representation theory, tropical geometry and cluster algebras / Lara Bossinger ; Gutachter: Peter Littelmann." Köln : Universitäts- und Stadtbibliothek Köln, 2018. http://d-nb.info/1163728381/34.
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Beckwith, Olivia D. "On Toric Symmetry of P1 x P2." Scholarship @ Claremont, 2013. http://scholarship.claremont.edu/hmc_theses/46.
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Toric varieties are a class of geometric objects with a combinatorial structure encoded in polytopes. P1 x P2 is a well known variety and its polytope is the triangular prism. Studying the symmetries of the triangular prism and its truncations can lead to symmetries of the variety. Many of these symmetries permute the elements of the cohomology ring nontrivially and induce nontrivial relations. We discuss some toric symmetries of P1 x P2, and describe the geometry of the polytope of the corresponding blowups, and analyze the induced action on the cohomology ring. We exhaustively compute the toric symmetries of P1 x P2.
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Shen, Chong. "Topic Analysis of Tweets on the European Refugee Crisis Using Non-negative Matrix Factorization." Scholarship @ Claremont, 2016. http://scholarship.claremont.edu/cmc_theses/1388.
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The ongoing European Refugee Crisis has been one of the most popular trending topics on Twitter for the past 8 months. This paper applies topic modeling on bulks of tweets to discover the hidden patterns within these social media discussions. In particular, we perform topic analysis through solving Non-negative Matrix Factorization (NMF) as an Inexact Alternating Least Squares problem. We accelerate the computation using techniques including tweet sampling and augmented NMF, compare NMF results with different ranks and visualize the outputs through topic representation and frequency plots. We observe that supportive sentiments maintained a strong presence while negative sentiments such as safety concerns have emerged over time.
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Sebestean, Magda. "Correspondance de McKay et equivalences derivees." Phd thesis, Université Paris-Diderot - Paris VII, 2005. http://tel.archives-ouvertes.fr/tel-00012064.
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Le premier chapitre montre par des méthodes toriques ($G-$graphes) que pour tout entier positif $n$, le quotient de l'espace affine à $n$ dimensions par le groupe cyclique $G_n$ d'ordre $2^n-1$ admet le $G_n$-schema de Hilbert comme résolution lisse crepante. Le deuxième chapitre contient des résultats sur les champs algébriques (construction du champ algébrique lisse associé à une log-paire). Le troisième chapitre montre l'équivalence entre la catégorie dérivée bornée des faisceaux cohérents $G_n-$équivariants sur l'espace affine et celle des faisceaux cohérents sur la résolution $G_n-$Hilb. Chapitre 4 donne une réalisation géométrique de la conjecture de Broué via la correspondance de McKay. L'annexe contient des résultats sur les groupes trihédraux, y compris un programme magma.
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Bergvall, Olof. "Cohomology of arrangements and moduli spaces." Doctoral thesis, Stockholms universitet, Matematiska institutionen, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-132822.
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This thesis mainly concerns the cohomology of the moduli spaces ℳ3[2] and ℳ3,1[2] of genus 3 curves with level 2 structure without respectively with a marked point and some of their natural subspaces. A genus 3 curve which is not hyperelliptic can be realized as a plane quartic and the moduli spaces 𝒬[2] and 𝒬1[2] of plane quartics without respectively with a marked point are given special attention. The spaces considered come with a natural action of the symplectic group Sp(6,𝔽2) and their cohomology groups thus become Sp(6,𝔽2)-representations. All computations are therefore Sp(6,𝔽2)-equivariant. We also study the mixed Hodge structures of these cohomology groups. The computations for ℳ3[2] are mainly via point counts over finite fields while the computations for ℳ3,1[2] primarily uses a description due to Looijenga in terms of arrangements associated to root systems. This leads us to the computation of the cohomology of complements of toric arrangements associated to root systems. These varieties come with an action of the corresponding Weyl group and the computations are equivariant with respect to this action.
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Miller, Jason A. "Okounkov Bodies of Borel Orbit Closures in Wonderful Group Compactifications." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1397599845.
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Dias, Guilherme dos Santos Martins. "Códigos projetivos parametrizados." Universidade Federal de Uberlândia, 2017. https://repositorio.ufu.br/handle/123456789/18286.
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CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorEste trabalho tem como objetivo estudar os parametros de um codigo projetivo gerado por um conjunto algebrico torico X que e parametrizado por uma quantidade nita de monomios em varias variaveis. Tambem podemos obter conjuntos algebricos toricos associados a matrizes de incidencia de grafos e cluters, e nestes casos obtemos resultados mais precisos, ja que os conjuntos algebricos toricos obtidos sao parametrizados por monomios com mesmo grau. Nos capitulos iniciais sao apresentados os conceitos basicos que servirao de ferramentas para atingir estes objetivos.
This work aims at studying the parameters of a projective code generated by an algebraic toric set X which is parameterized by a nite number of monomials in several variables. We also can obtain algebraic toric sets associated to graph or clutter incidence matrices and in these cases we obtain more precise results since the algebraic toric sets which are obtained are parameterized by monomials of the same degree. In the rst chapters we introduce basic concepts which will serve as tools to reach our aim.
Dissertação (Mestrado)
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Larsen, Paul L. "Applied Mori theory of the moduli space of stable pointed rational curves." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät II, 2011. http://dx.doi.org/10.18452/16330.
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Diese Dissertation befasst sich mit Fragen über den Modulraum M_{0,n} der stabilen punktierten rationalen Kurven, die durch das Mori-Programm motiviert sind. Insbesondere studieren wir den nef-Kegel (Chapter 2), den Cox-Ring (Chapter 3), und den Kegel der beweglichen Kurven (Chapter 4). In Kapitel 2 beweisen wir Fultons Vermutung für M_{0,n}, nWe investigate questions motivated by Mori''s program for the moduli space of stable pointed rational curves, M_{0,n}. In particular, we study its nef cone (Chapter 2), its Cox ring (Chapter 3), and its cone of movable curves (Chapter 4). In Chapter 2, we prove Fulton''s conjecture for M_{0,n} for n less than or equal to 7, which states that any divisor on these moduli spaces non-negatively intersecting all so-called F-curves is linearly equivalent to an effective sum of boundary divisors. As a corollary, it follows that a divisor is nef if and only if the divisor intersects all F-curves non-negatively. By duality, we thus recover Keel and McKernan''s result that the F-curves generate the closed cone of curves when n is less than or equal to seven, but with methods that do not rely on negativity properties of the canonical bundle that fail for higher n. Chapter 3 initiates a study of relations among generators of the Cox ring of M_{0,n}. We first prove a `relation-free'' result that exhibits polynomial subrings of the Cox ring in boundary section variables. In the opposite direction, we exhibit multidegrees such that the corresponding graded parts meet the ideal of relations non-trivially. In Chapter 4, we study the so-called complete intersection cone for the three-fold M_{0,6}. For a smooth projective variety X, this cone is defined as the closure of curve classes obtained as intersections of the dimension of X minus one very ample divisors. The complete intersection cone is contained in the cone of movable curves, which is dual to the cone of pseudoeffective divisors. We show that, for a series of toric birational models for M_{0,6}, the complete intersection and movable cones coincide, while for M_{0,6}, there is strict containment.
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Kuyumzhiyan, Karine. "Actions des groupes algébriques sur les variétés affines et normalité d'adhérences d'orbites." Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00685202.
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Cette thèse est consacrée aux actions des groupes de transformations algébriques sur les variétés affines algébriques. Dans la première partie, on étudie la normalité des adhérences des orbites de tore maximal dans un module rationnel de groupe algébrique simple. La seconde partie porte sur les actions du groupe d'automorphismes d'une variété affine. Nous nous intéressons aux propriétés de transitivité et de transitivité multiple de ces actions sur le lieu lisse de la variété.
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Koshelev, Dmitrii. "Nouvelles applications des surfaces rationnelles et surfaces de Kummer généralisées sur des corps finis à la cryptographie à base de couplages et à la théorie des codes BCH." Thesis, université Paris-Saclay, 2021. http://www.theses.fr/2021UPASM001.
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Il y a une théorie bien développée de ce qu'on appelle codes toriques, c'est-à-dire des codes de géométrie algébrique sur des variétés toriques sur un corps fini. A côté des tores et variétés toriques ordinaires (c'est-à-dire déployés), il y a non-déployés. La thèse est donc dédiée à l'étude des codes de géométrie algébrique sur les derniersThere is well developed theory of so-called toric codes, i.e., algebraic geometry codes on toric varieties over a finite field. Besides ordinary (i.e., split) tori and toric varieties there are non-split ones. Therefore the thesis is dedicated to the study of algebraic geometry codes on the latter
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Nardi, Jade. "Quelques retombées de la géométrie des surfaces toriques sur un corps fini sur l'arithmétique et la théorie de l'information." Thesis, Toulouse 3, 2019. http://www.theses.fr/2019TOU30051.
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Cette thèse, à la frontière entre les mathématiques et l'informatique, est consacrée en partie à l'étude des paramètres et des propriétés des codes de Goppa sur les surfaces de Hirzebruch. D'un point de vue arithmétique, la théorie des codes correcteurs a ravivé la question du nombre de points rationnels d'une variété définie sur un corps fini, qui semblait résolue par la formule de Lefschetz. La distance minimale de codes géométriques donne un majorant du nombre de points rationnels d'une hypersurface d'une variété donnée et de classe de Picard fixée. Ce majorant étant le plus souvent atteint pour les courbes très réductibles, il est naturel de se concentrer sur les courbes irréductibles pour affiner les bornes. On présente une stratégie globale pour majorer le nombre de points d'une variété en fonction de son ambiant et d'invariants géométriques, notamment liés à la théorie de l'intersection. De plus, une méthode de ce type pour les courbes d'une surface torique est développée en adaptant l'idée de F.J Voloch et K.O. Sthör aux variétés toriques. Enfin, on s'intéresse aux protocoles de Private Information Retrivial, qui visent à assurer qu'un utilisateur puisse accéder à une entrée d'une base de données sans révéler d'information sur l'entrée au propriétaire de la base de données. Un protocole basé sur des codes sur des plans projectifs pondérés est proposé ici. Il améliore les protocoles existants en résistant à la collusion de serveurs, au prix d'une grande perte de capacité de stockage. On pallie ce problème grâce à la méthode du lift qui permet la construction de familles de codes asymptotiquement bonnes, avec les mêmes propriétés localesA part of this thesis, at the interface between Computer Science and Mathematics, is dedicated to the study of the parameters ans properties of Goppa codes over Hirzebruch surfaces. From an arithmetical perspective, the question about number of rational points of a variety defined over a finite field, which seemed dealt with by Lefchetz formula, regained interest thanks to error correcting codes. The minimum distance of an algebraic-geometric codes provides an upper bound of the number of rational points of a hypersurface of a given variety and with a fixed Picard class. Since reducible curves are most likely to reach this bound, one can focus on irreducible curves to get sharper bounds. A global strategy to bound the number of points on a variety depending on its ambient space and some of its geometric invariants is exhibited here. Moreover we develop a method for curves on toric surfaces by adapting F.J. Voloch et K.O. Sthör's idea on toric varieties. Finally, we interest in Private Information Retrivial protocols, which aim to ensure that a user can access an entry of a database without revealing any information on it to the database owner. A PIR protocol based on codes over weighted projective planes is displayed here. It enhances other protocols by offering a resistance to servers collusions, at the expense of a loss of storage capacity. This issue is fixed by a lifting process, which leads to asymptotically good families of codes, with the same local properties
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Xia, Runlian. "Les espaces de Hardy locaux à valeurs opératorielle et les applications sur les opérateurs pseudo-différentiels." Thesis, Bourgogne Franche-Comté, 2017. http://www.theses.fr/2017UBFCD084/document.
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Le but de cette thèse est d’étudier l’analyse sur les espaces hpc(Rd,M), la version locale des espaces de Hardy à valeurs opératorielles construits par Tao Mei. Les espaces de Hardy locaux à valeurs opératorielles sont définis par les g-fonctions de Littlewood-Paley tronquées et les fonctions intégrables de Lusin tronquées associées au noyau de Poisson. Nous développons la théorie de Calderón-Zygmund sur hpc(Rd,M); nous étudions la dualité hpcbmocq et l’interpolation. D’après ces résultats, nous obtenons la caractérisation générale de hpc(Rd,M) en remplaçant le noyau de Poisson par des fonctions tests raisonnables. Ceci joue un rôle important dans la décomposition atomique lisse de h1c(Rd,M). En même temps, nous étudions aussi les espaces de Triebel-Lizorkin inhomogènes à valeurs opératorielles Fpα,c(Rd,M). Comme dans le cas classique, ces espaces sont connectés avec des espaces de Hardy locaux à valeurs opératorielles par les potentiels de Bessel. Grâce à l’aide de la théorie de Calderón-Zygmund, nous obtenons les caractérisations de type LittlewoodPaley et de type Lusin par des noyaux plus généraux. Ces caractérisations nous permettent d’étudier différentes propriétés de Fpα,c(Rd,M), en particulier, la décomposition atomique lisse. Ceci est une extension et une amélioration de la décomposition atomique précédente de h1c(Rd,M). Comme une application importante de cette décomposition atomique lisse, nous montrons la bornitude d’opérateurs pseudo-différentiels avec les symboles réguliers à valeurs opératorielles sur des espaces de Triebel-Lizorkin Fpα,c(Rd,M), pour α ∈ R et 1 ≤ p ≤ ∞. Finalement, grâce à la transférence, nous obtenons aussi la Fpα,c-bornitude d’opérateurs pseudo-différentiels sur les tores quantiquesThis thesis is devoted to the study of the analysis on the spaces hpc(Rd,M), the local version of operator-valued Hardy spaces studied by Tao Mei. The operator-valued local Hardy spaces are defined by the truncated Littlewood-Paley g-functions and the truncated Lusin square functions associated to the Poisson kernel. We develop the Calderón-Zygmund theory on hpc(Rd,M), and study the hpc-bmocq duality and the interpolation. Based on these results, we obtain general characterization of hpc(Rd,M) which states that the Poisson kernel can be replaced by any reasonable test function. This characterization plays an important role in the smooth atomic decomposition of h1c(Rd,M). We also investigate the operator-valued inhomogeneous Triebel-Lizorkin spaces Fpα,c(Rd,M). Like in the classical case, these spaces are connected with the operator-valued local Hardy spaces via Bessel potentials. Then by the aid of the Calderón-Zygmund theory, we obtain the Littlewood-Paley type and the Lusin type characterizations of Fpα,c(Rd,M) by more general kernels. These characterizations allow us to study various properties of Fpα,c(Rd,M), in particular, the smooth atomic decomposition. This is an extension and an improvement of the previous atomic decomposition of h1c(Rd,M). As an important application of this smooth atomic decomposition, we show the boundedness of pseudo-differential operators with regular operator-valued symbols on Triebel-Lizorkin spaces Fpα,c(Rd,M), for α ∈ R and 1 ≤ p ≤ ∞. Finally, by virtue of transference, we obtain the Fpα,c-boundedness of pseudo-differential operators on quantum tori
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De, Notariis Kevin. "Light hyperweak new gauge bosons from kinetic mixing in string models." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/19491/.
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String theory is at the moment our best candidate for a unified quantum theory of gravity, aiming to reconcile all the known (and unknown) interactions with gravity as well as provide insights for currently mysterious phenomena that the Standard Model and the modern Cosmology are not able to explain. In fact, it is believed that most of the problems associated to the Standard Model can indeed be resolved in string theory. Supersymmetry is supposed to be an elegant solution to the Hierarchy problem (even though more and more stringent bounds in this direction are being placed by the fact that we have been unable to experimentally find supersymmetry yet), while all the axions that compactifications bring into play can be used to resolve the strong CP problem as well as provide good candidates for Dark Matter. Inflationary models can also be constructed in string theory, providing, then, the most diffused solution to the Horizon problem. This work, in particular, is formulated in type IIB string theory compactified on an orientifolded Calabi-Yau three-fold in LARGE Volume Scenario (LVS) and focuses on the stabilisation of all the moduli in play compatible with the construction of a hidden gauge sector whose gauge boson kinetically mixes to the visible sector U(1), acquiring a mass via a completely stringy process resulting in the St{\"u}ckelberg mechanism. The "compatibility" regards the fact that certain experimental bounds should be respected combined with recent data extrapolated by Coherent Elastic Neutrino-Nucleus Scattering (CE$\nu$NS) events at the Spallation Neutron Source at Oak Ridge National Laboratory. We are going to see that in this context we will be able to fix all the moduli as well as present a brane and fluxes set-up reproducing the correct mass and coupling of the hidden gauge boson. We also get a TeV scale supersymmetry, since the gravitino in this model will be of order O(TeV), with an uplifted vacuum to reproduce a de Sitter universe as well.
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Görlach, Paul. "Projective geometry, toric algebra and tropical computations." 2020. https://ul.qucosa.de/id/qucosa%3A73043.
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Nguyen, Dang Hop. "Homological and combinatorial properties of toric face rings." Doctoral thesis, 2012. https://repositorium.ub.uni-osnabrueck.de/handle/urn:nbn:de:gbv:700-2012082110274.
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Toric face rings are a generalization of Stanley-Reisner rings and affine monoid rings. New problems and results are obtained by a systematic study of toric face rings, shedding new lights to the understanding of Stanley-Reisner rings and affine monoid rings. We study algebra retracts of Stanley-Reisner rings, in particular, classify all the $\mathbb{Z}$-graded algebra retracts. We consider the Koszul property of toric face rings via Betti numbers and properties of the defining ideal. The last chapter is devoted to local cohomology of seminormal toric face rings and applications to singularities of toric face rings in positive characteristics.
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(6598226), Avram W. Steiner. "A-Hypergeometric Systems and D-Module Functors." Thesis, 2019.
Find full textAbstract:
Let A be a d by n integer matrix. Gel'fand et al.\ proved that most A-hypergeometric systems have an interpretation as a Fourier–Laplace transform of a direct image. The set of parameters for which this happens was later identified by Schulze and Walther as the set of not strongly resonant parameters of A. A similar statement relating A-hypergeometric systems to exceptional direct images was proved by Reichelt. In the first part of this thesis, we consider a hybrid approach involving neighborhoods U of the torus of A and consider compositions of direct and exceptional direct images. Our main results characterize for which parameters the associated A-hypergeometric system is the inverse Fourier–Laplace transform of such a "mixed Gauss–Manin system".
If the semigroup ring of A is normal, we show that every A-hypergeometric system is "mixed Gauss–Manin".
In the second part of this thesis, we use our notion of mixed Gauss–Manin systems to show that the projection and restriction of a normal A-hypergeometric system to the coordinate subspace corresponding to a face are isomorphic up to cohomological shift; moreover, they are essentially hypergeometric. We also show that, if A is in addition homogeneous, the holonomic dual of an A-hypergeometric system is itself A-hypergeometric. This extends a result of Uli Walther, proving a conjecture of Nobuki Takayama in the normal homogeneous case.
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Schwerteck, Florian [Verfasser]. "Real algebraic varieties with trivial canonical class and toric geometry / Florian Schwerteck." 2010. http://d-nb.info/1004706243/34.
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Wang, Qing. "On the tori and Cartan subalgebras of Lie algebras of Cartan type." 1992. http://catalog.hathitrust.org/api/volumes/oclc/29012163.html.
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Mahanta, Snigdhayan [Verfasser]. "Algebraic aspects of noncommutative tori: the Riemann-Hilbert correspondence / vorgeleegt von Snigdhayan Mahanta." 2007. http://d-nb.info/985411716/34.
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Fischer, Benjamin Parker. "Perturbed polyhedra and the construction of local Euler-Maclaurin formulas." Thesis, 2016. https://hdl.handle.net/2144/17733.
Full textAbstract:
A polyhedron P is a subset of a rational vector space V bounded by hyperplanes. If we fix a lattice in V , then we may consider the exponential integral and sum, two meromorphic functions on the dual vector space which serve to generalize the notion of volume of and number of lattice points contained in P, respectively. In 2007, Berline and Vergne constructed an Euler-Maclaurin formula that relates the exponential sum of a given polyhedron to the exponential integral of each face. This formula was "local", meaning that the coefficients in this formula had certain properties independent of the given polyhedron. In this dissertation, the author finds a new construction for this formula which is very different from that of Berline and Vergne. We may 'perturb' any polyhedron by tranlsating its bounding hyperplanes. The author defines a ring of differential operators R(P) on the exponential volume of the perturbed polyhedron. This definition is inspired by methods in the theory of toric varieties, although no knowledge of toric varieties is necessary to understand the construction or the resulting Euler-Maclaurin formula. Each polyhedron corresponds to a toric variety, and there is a dictionary between combinatorial properties of the polyhedron and algebro-geometric properties of this variety. In particular, the equivariant cohomology ring and the group of equivariant algebraic cycles on the corresponding toric variety are equal to a quotient ring and subgroup of R(P), respectively. Given an inner product (or, more generally, a complement map) on V , there is a canonical section of the equivariant cohomology ring into the group of algebraic cycles. One can use the image under this section of a particular differential operator called the Todd class to define the Euler-Maclaurin formula. The author shows that this formula satisfies the same properties which characterize the Berline-Vergne formula.
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Girard, Vincent. "Géométrie algébrique : théorèmes d'annulation sur les variétés toriques." Thèse, 2017. http://hdl.handle.net/1866/20200.
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