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Tesi sul tema "Algebraic number theory"
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1
Röttger, Christian Gottfried Johannes. "Counting problems in algebraic number theory". Thesis, University of East Anglia, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327407.
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2
Swanson, Colleen M. "Algebraic number fields and codes /". Connect to online version, 2006. http://ada.mtholyoke.edu/setr/websrc/pdfs/www/2006/172.pdf.
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3
Hughes, Garry. "Distribution of additive functions in algebraic number fields". Title page, contents and summary only, 1987. http://web4.library.adelaide.edu.au/theses/09SM/09smh893.pdf.
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4
McCoy, Daisy Cox. "Irreducible elements in algebraic number fields". Diss., Virginia Tech, 1990. http://hdl.handle.net/10919/39950.
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5
Gaertner, Nathaniel Allen. "Special Cases of Density Theorems in Algebraic Number Theory". Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/33153.
Testo completoAbstract (sommario):
This paper discusses the concepts in algebraic and analytic number theory used in the proofs of Dirichlet's and Cheboterev's density theorems. It presents special cases of results due to the latter theorem for which greatly simplified proofs exist.Master of Science
6
PASINI, FEDERICO WILLIAM. "Classifying spaces for knots: new bridges between knot theory and algebraic number theory". Doctoral thesis, Università degli Studi di Milano-Bicocca, 2016. http://hdl.handle.net/10281/129230.
Testo completoAbstract (sommario):
In this thesis we discuss how, in the context of knot theory, the classifying space of a knot group for the family of meridians arises naturally. We provide an explicit construction of a model for that space, which is particularly nice in the case of a prime knot. We then show that this classifying space controls the behaviour of the finite branched coverings of the knot. We present a 9-term exact sequence for knot groups that strongly resembles the Poitou-Tate exact sequence for algebraic number fields. Finally, we show that the homology of the classifying space behaves towards the former sequence as Shafarevich groups do towards the latter.
7
Rozario, Rebecca. "The Distribution of the Irreducibles in an Algebraic Number Field". Fogler Library, University of Maine, 2003. http://www.library.umaine.edu/theses/pdf/RozarioR2003.pdf.
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8
Nyqvist, Robert. "Algebraic Dynamical Systems, Analytical Results and Numerical Simulations". Doctoral thesis, Växjö : Växjö University Press, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:vxu:diva-1142.
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9
Yan, Song Yuan. "On the algebraic theories and computations of amicable numbers". Thesis, University of York, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284133.
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10
Haydon, James Henri. "Étale homotopy sections of algebraic varieties". Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:88019ba2-a589-4179-ad7f-1eea234d284c.
Testo completoAbstract (sommario):
We define and study the fundamental pro-finite 2-groupoid of varieties X defined over a field k. This is a higher algebraic invariant of a scheme X, analogous to the higher fundamental path 2-groupoids as defined for topological spaces. This invariant is related to previously defined invariants, for example the absolute Galois group of a field, and Grothendieck’s étale fundamental group. The special case of Brauer-Severi varieties is considered, in which case a “sections conjecture” type theorem is proved. It is shown that a Brauer-Severi variety X has a rational point if and only if its étale fundamental 2-groupoid has a special sort of section.
11
Green, Benjamin. "Galois representations attached to algebraic automorphic representations". Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:77f01cbc-65d1-480d-ae3a-0a039a76671a.
Testo completoAbstract (sommario):
This thesis is concerned with the Langlands program; namely the global Langlands correspondence, Langlands functoriality, and a conjecture of Gross. In chapter 1, we cover the most important background material needed for this thesis. This includes material on reductive groups and their root data, the definition of automorphic representations and a general overview of the Langlands program, and Gross' conjecture concerning attaching l-adic Galois representations to automorphic representations on certain reductive groups G over ℚ. In chapter 2, we show that odd-dimensional definite unitary groups satisfy the hypotheses of Gross' conjecture and verify the conjecture in this case using known constructions of automorphic l-adic Galois representations. We do this by verifying a specific case of a generalisation of Gross' conjecture; one should still get l-adic Galois representations if one removes one of his hypotheses but with the cost that their image lies in CG(ℚl) as opposed to LG(ℚl). Such Galois representations have been constructed for certain automorphic representations on G, a definite unitary group of arbitrary dimension, and there is a map CG(ℚl) → LG(ℚl) precisely when G is odd-dimensional. In chapter 3, which forms the main part of this thesis, we show that G = Un(B) where B is a rational definite quaternion algebra satisfies the hypotheses of Gross' conjecture. We prove that one can transfer a cuspidal automorphic representation π of G to a π' on Sp2n (a Jacquet-Langlands type transfer) provided it is Steinberg at some finite place. We also prove this when B is indefinite. One can then transfer πâ² to an automorphic representaion of GL2n+1 using the work of Arthur. Finally, one can attach l-adic Galois representations to these automorphic representations on GL2n+1, provided we assume Ï is regular algebraic if B is indefinite, and show that they have orthogonal image.
12
Meyer, Nicolas David. "Determination of Quadratic Lattices by Local Structure and Sublattices of Codimension One". OpenSIUC, 2015. https://opensiuc.lib.siu.edu/dissertations/1026.
Testo completoAbstract (sommario):
For definite quadratic lattices over the rings of integers of algebraic number fields, it is shown that lattices are determined up to isometry by their local structure and sublattices of codimension 1. In particular, a theorem of Yoshiyuki Kitaoka for $\mathbb{Z}$-lattices is generalized to definite lattices over algebraic number fields.
13
Trad, Mohamad. "The proof of Fermat's last theorem". CSUSB ScholarWorks, 2000. https://scholarworks.lib.csusb.edu/etd-project/1690.
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14
Blackhurst, Jonathan H. "Proven Cases of a Generalization of Serre's Conjecture". Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1386.pdf.
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15
Cobbe, Alessandro. "Steinitz classes of tamely rami ed Galois extensions of algebraic number fields". Doctoral thesis, Scuola Normale Superiore, 2009. http://hdl.handle.net/11384/85661.
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16
Briggs, Matthew Edward. "An Introduction to the General Number Field Sieve". Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/36618.
Testo completoAbstract (sommario):
With the proliferation of computers into homes and businesses and the explosive growth rate of the Internet, the ability to conduct secure electronic communications and transactions has become an issue of vital concern. One of the most prominent systems for securing electronic information, known as RSA, relies upon the fact that it is computationally difficult to factor a "large" integer into its component prime integers. If an efficient algorithm is developed that can factor any arbitrarily large integer in a "reasonable" amount of time, the security value of the RSA system would be nullified. The General Number Field Sieve algorithm is the fastest known method for factoring large integers. Research and development of this algorithm within the past five years has facilitated factorizations of integers that were once speculated to require thousands of years of supercomputer time to accomplish. While this method has many unexplored features that merit further research, the complexity of the algorithm prevents almost anyone but an expert from investigating its behavior. We address this concern by first pulling together much of the background information necessary to understand the concepts that are central in the General Number Field Sieve. These concepts are woven together into a cohesive presentation that details each theory while clearly describing how a particular theory fits into the algorithm. Formal proofs from existing literature are recast and illuminated to clarify their inner-workings and the role they play in the whole process. We also present a complete, detailed example of a factorization achieved with the General Number Field Sieve in order to concretize the concepts that are outlined.Master of Science
17
Suresh, Arvind. "On the Characterization of Prime Sets of Polynomials by Congruence Conditions". Scholarship @ Claremont, 2015. http://scholarship.claremont.edu/cmc_theses/993.
Testo completoAbstract (sommario):
This project is concerned with the set of primes modulo which some monic, irreducible polynomial over the integers has a root, called the Prime Set of the polynomial. We completely characterise these sets for degree 2 polynomials, and develop sufficient machinery from algebraic number theory to show that if the Galois group of a monic, irreducible polynomial over the integers is abelian, then its Prime Set can be written as the union of primes in some congruence classes modulo some integer.
18
Banaszak, Grzegorz. "Algebraic K-theory of number fields and rings of integers and the Stickelberger ideal /". The Ohio State University, 1990. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487676261012829.
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19
Kaplan, Elliot. "Initial Embeddings in the Surreal Number Tree". Ohio University Honors Tutorial College / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ouhonors1429615758.
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20
Hsu, Catherine. "Higher Congruences Between Modular Forms". Thesis, University of Oregon, 2018. http://hdl.handle.net/1794/23742.
Testo completoAbstract (sommario):
In his seminal work on modular curves and the Eisenstein ideal, Mazur studied the existence of congruences between certain Eisenstein series and newforms, proving that Eisenstein ideals associated to weight 2 cusp forms of prime level are locally principal. In this dissertation, we re-examine Eisenstein congruences, incorporating a notion of “depth of congruence,” in order to understand the local structure of Eisenstein ideals associated to weight 2 cusp forms of squarefree level N. Specifically, we use a commutative algebra result of Berger, Klosin, and Kramer to bound the depth of mod p Eisenstein congruences (from below) by the p-adic valuation of φ(N). We then show how this depth of congruence controls the local principality of the associated Eisenstein ideal.
21
Silberstein, Aaron. "Anabelian Intersection Theory". Thesis, Harvard University, 2012. http://dissertations.umi.com/gsas.harvard:10141.
Testo completoAbstract (sommario):
Let F be a field finitely generated and of transcendence degree 2 over \(\bar{\mathbb{Q}}\). We describe a correspondence between the smooth algebraic surfaces X defined over \(\bar{\mathbb{Q}}\) with field of rational functions F and Florian Pop’s geometric sets of prime divisors on \(Gal(\bar{F}/F)\), which are purely group-theoretical objects. This allows us to give a strong anabelian theorem for these surfaces. As a corollary, for each number field K, we give a method to construct infinitely many profinite groups \(\Gamma\) such that \(Out_{cont} (\Gamma)\) is isomorphic to \(Gal(\bar{K}/K)\), and we find a host of new categories which answer the Question of Ihara/Conjecture of Oda-Matsumura.Mathematics
22
Dang, Vinh Xuan. "Three-Dimensional Galois Representations and a Conjecture of Ash, Doud, and Pollack". BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2697.
Testo completoAbstract (sommario):
In the 1970s and 1980s, Jean-Pierre Serre formulated a conjecture connecting two-dimensional Galois representations and modular forms. The conjecture came to be known as Serre's modularity conjecture. It was recently proved by Khare and Wintenberger in 2008. Serre's conjecture has various important consequences in number theory. Most notably, it played a key role in the proof of Fermat's last theorem. A natural question is, what is the analogue of Serre's conjecture for higher dimensional Galois representations? In 2002, Ash, Doud and Pollack formulated a precise statement for a higher dimensional analogue of Serre's conjecture. They also provided numerous computational examples as evidence for this generalized conjecture. We consider the three-dimensional version of the Ash-Doud-Pollack conjecture. We find specific examples of three-dimensional Galois representations and computationally verify the generalized conjecture in all these examples.
23
Munoz, Susana L. "A Fundamental Unit of O_K". CSUSB ScholarWorks, 2015. https://scholarworks.lib.csusb.edu/etd/133.
Testo completoAbstract (sommario):
In the classical case we make use of Pells equation to compute units in the ring OF. Consider the parallel to the classical case and the quadratic field extension that creates the ring OK. We use the generalized Pell's equation to find the units in this ring since they are solutions. Through the use of continued fractions we may further characterize this ring and compute its units.
24
Harper, John-Paul. "The class number one problem in function fields". Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/53619.
Testo completoAbstract (sommario):
Thesis (MComm)--Stellenbosch University, 2003.ENGLISH ABSTRACT: In this dissertation I investigate the class number one problem in function fields. More precisely I give a survey of the current state of research into extensions of a rational function field over a finite field with principal ring of integers. I focus particularly on the quadratic case and throughout draw analogies and motivations from the classical number field situation. It was the "Prince of Mathematicians" C.F. Gauss who first undertook an in depth study of quadratic extensions of the rational numbers and the corresponding rings of integers. More recently however work has been done in the situation of function fields in which the arithmetic is very similar. I begin with an introduction into the arithmetic in function fields over a finite field and prove the analogies of many of the classical results. I then proceed to demonstrate how the algebra and arithmetic in function fields can be interpreted geometrically in terms of curves and introduce the associated geometric language. After presenting some conjectures, I proceed to give a survey of known results in the situation of quadratic function fields. I present also a few results of my own in this section. Lastly I state some recent results regarding arbitrary extensions of a rational function field with principal ring of integers and give some heuristic results regarding class groups in function fields.
AFRIKAANSE OPSOMMING: In hierdie tesis ondersoek ek die klasgetal een probleem in funksieliggame. Meer spesifiek ondersoek ek die huidige staat van navorsing aangaande uitbreidings van 'n rasionale funksieliggaam oor 'n eindige liggaam sodat die ring van heelgetalle 'n hoofidealgebied is. Ek kyk in besonder na die kwadratiese geval, en deurgaans verwys ek na die analoog in die klassieke getalleliggaam situasie. Dit was die beroemde wiskundige C.F. Gauss wat eerste kwadratiese uitbreidings van die rasionale getalle en die ooreenstemende ring van heelgetalle in diepte ondersoek het. Onlangs het wiskundiges hierdie probleme ook ondersoek in die situasie van funksieliggame oor 'n eindige liggaam waar die algebraïese struktuur baie soortgelyk is. Ek begin met 'n inleiding tot die rekenkunde in funksieliggame oor 'n eindige liggaam en bewys die analogie van baie van die klassieke resultate. Dan verduidelik ek hoe die algebra in funksieliggame geometries beskou kan word in terme van kurwes en gee 'n kort inleiding tot die geometriese taal. Nadat ek 'n paar vermoedes bespreek, gee ek 'n oorsig van wat alreeds vir quadratiese funksieliggame bewys is. In hierdie afdeling word 'n paar resultate van my eie ook bewys. Dan vermeld ek 'n paar resultate aangaande algemene uitbreidings van 'n rasionale funksieliggaam oor 'n eindige liggaam waar die van ring heelgetalle 'n hoofidealgebied is. Laastens verwys ek na 'n paar heurisitiese resultate aangaande klasgroepe in funksieliggame.
25
Massold, Heinrich. "Labile und relative Reduktionstheorie über Zahlkörpern". Bonn : Mathematisches Institut der Universität, 2003. http://catalog.hathitrust.org/api/volumes/oclc/54890700.html.
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26
Masters, Joseph David. "Lengths and homology of hyperbolic 3-manifolds /". Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.
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27
Vonk, Jan Bert. "The Atkin operator on spaces of overconvergent modular forms and arithmetic applications". Thesis, University of Oxford, 2015. http://ora.ox.ac.uk/objects/uuid:081e4e46-80c1-41e7-9154-3181ccb36313.
Testo completoAbstract (sommario):
We investigate the action of the Atkin operator on spaces of overconvergent p-adic modular forms. Our contributions are both computational and geometric. We present several algorithms to compute the spectrum of the Atkin operator, as well as its p-adic variation as a function of the weight. As an application, we explicitly construct Heegner-type points on elliptic curves. We then make a geometric study of the Atkin operator, and prove a potential semi-stability theorem for correspondences. We explicitly determine the stable models of various Hecke operators on quaternionic Shimura curves, and make a purely geometric study of canonical subgroups.
28
Salt, Brittney M. "MONOID RINGS AND STRONGLY TWO-GENERATED IDEALS". CSUSB ScholarWorks, 2014. https://scholarworks.lib.csusb.edu/etd/31.
Testo completoAbstract (sommario):
This paper determines whether monoid rings with the two-generator property have the strong two-generator property. Dedekind domains have both the two-generator and strong two-generator properties. How common is this? Two cases are considered here: the zero-dimensional case and the one-dimensional case for monoid rings. Each case is looked at to determine if monoid rings that are not PIRs but are two-generated have the strong two-generator property. Full results are given in the zero-dimensional case, however only partial results have been found for the one-dimensional case.
29
Lavallee, Melisa Jean. "Dihedral quintic fields with a power basis". Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/2788.
Testo completoAbstract (sommario):
Cryptography is defined to be the practice and studying of hiding information
and is used in applications present today; examples include the security of ATM
cards and computer passwords ([34]). In order to transform information to make it
unreadable, one needs a series of algorithms. Many of these algorithms are based on
elliptic curves because they require fewer bits. To use such algorithms, one must find
the rational points on an elliptic curve. The study of Algebraic Number Theory, and
in particular, rare objects known as power bases, help determine what these rational
points are. With such broad applications, studying power bases is an interesting
topic with many research opportunities, one of which is given below.
There are many similarities between Cyclic and Dihedral fields of prime degree;
more specifically, the structure of their field discriminants is comparable. Since the
existence of power bases (i.e. monogenicity) is based upon finding solutions to the
index form equation - an equation dependant on field discriminants - does this imply
monogenic properties of such fields are also analogous?
For instance, in [14], Marie-Nicole Gras has shown there is only one monogenic
cyclic field of degree 5. Is there a similar result for dihedral fields of degree 5? The
purpose of this thesis is to show that there exist infinitely many monogenic dihedral
quintic fields and hence, not just one or finitely many. We do so by using a well-
known family of quintic polynomials with Galois group D₅. Thus, the main theorem
given in this thesis will confirm that monogenic properties between cyclic and dihedral
quintic fields are not always correlative.
30
Rosca, Georgiana-Miruna. "On algebraic variants of Learning With Errors". Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEN063.
Testo completoAbstract (sommario):
La cryptographie à base de réseaux euclidiens repose en grande partie sur l’utilisation du problème Learning With Errors (LWE) comme fondation de sécurité. Ce problème est au moins aussi difficile que les problèmes standards portant sur les réseaux, mais les primitives cryptographiques qui l’utilisent sont inefficaces en termes de consommation en temps et en espace. Les problèmes Polynomial Learning WithErrors (PLWE), dual Ring Learning With Errors (dual-RLWE) et primal Ring Learning With Errors(primal-RLWE) sont trois variantes de LWE qui utilisent des structures algébriques supplémentaires afin de pallier les inconvénients ci-dessus. Le problème PLWE est paramétré par un polynôme f, alors que dual-RLWE et primal-RLWE sont définis à l’aide de l’anneau d’entiers d’un corps de nombres.Ces problèmes, dits algébriques, sont eux-mêmes au moins aussi difficiles que des problèmes standards portant sur les réseaux, mais, dans leur cas, les réseaux impliqués appartiennent à des classes restreintes.Dans cette thèse, nous nous intéressons aux liens entre les variantes algébriques de LWE.Tout d’abord, nous montrons que pour une vaste classe de polynômes de définition, il existe des réductions (non-uniformes) entre dual-RLWE, primal-RLWE et PLWE pour lesquelles l’amplification des paramètres peut être contrôlée. Ces résultats peuvent être interprétés comme une indication forte de l’équivalence calculatoire de ces problèmes.Ensuite, nous introduisons une nouvelle variante algébrique de LWE, Middle-Product Learning WithErrors (MP-LWE). On montre que ce problème est au moins aussi difficile que PLWE pour beaucoup de polynômes de définition f. Par conséquent, un système cryptographique reposant sur MP-LWE reste sûr aussi longtemps qu’une de ces instances de PLWE reste difficile à résoudre.Enfin, nous montrons la pertinence cryptographique de MP-LWE en proposant un protocole de chiffrement asymétrique et une signature digitale dont la sécurité repose sur la difficulté présumée de MP-LWELattice-based cryptography relies in great parts on the use of the Learning With Errors (LWE) problemas hardness foundation. This problem is at least as hard as standard worst-case lattice problems, but the primitives based on it usually have big key sizes and slow algorithms. Polynomial Learning With Errors (PLWE), dual Ring Learning With Errors (dual-RLWE) and primal Ring Learning WithErrors (primal-RLWE) are variants of LWE which make use of extra algebraic structures in order to fix the above drawbacks. The PLWE problem is parameterized by a polynomial f, while dual-RLWE andprimal-RLWE are defined using the ring of integers of a number field. These problems, which we call algebraic, also enjoy reductions from worst-case lattice problems, but in their case, the lattices involved belong to diverse restricted classes. In this thesis, we study relationships between algebraic variants of LWE.We first show that for many defining polynomials, there exist (non-uniform) reductions betweendual-RLWE, primal-RLWE and PLWE that incur limited parameter losses. These results could be interpretedas a strong evidence that these problems are qualitatively equivalent.Then we introduce a new algebraic variant of LWE, Middle-Product Learning With Errors (MP-LWE). We show that this problem is at least as hard as PLWE for many defining polynomials f. As a consequence,any cryptographic system based on MP-LWE remains secure as long as one of these PLWE instances remains hard to solve.Finally, we illustrate the cryptographic relevance of MP-LWE by building a public-key encryption scheme and a digital signature scheme that are proved secure under the MP-LWE hardness assumption
31
Carlos, Tatiana Bertoldi. "Abordagem algebrica e geometrica de reticulados". [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/306605.
Testo completoAbstract (sommario):
Orientador: Sueli Irene Rodrigues CostaTese (doutorado) - Universidade Estadual de Campinas, Instituto de Matematica, Estatistica e Computação Cientifica
Made available in DSpace on 2018-08-10T04:41:55Z (GMT). No. of bitstreams: 1 Carlos_TatianaBertoldi_D.pdf: 779190 bytes, checksum: d0ff8f53ff44a5f19c7edb1427cd1a82 (MD5) Previous issue date: 2007
Resumo: Neste trabalho abordamos a construção de reticulados usando propriedades da teoria dos números algébricos. Enfocamos particularmente a construção, como reticulado ideal, de rotações do reticulado n-dimensional dos inteiros, usando corpos ciclotômicos. Reticulados desta forma tem se mostrado uma eficiente ferramenta para obtenção de bons esquemas de codificação para canais com desvanecimento, pois permitem estimativas da distância produto e diversidade, parâmetros que controlam a probabilidade de erro no envio de informações por estes canais. Apresentamos uma nova construção de tais reticulados no caso em que n é uma potência de 2, através do subcorpo maximal real do n-ésimo corpo ciclotômico. Estabelecemos também condições para que um reticulado ideal seja rotação do reticulado n-dimensional dos inteiros, usando algoritmos de redução de base, LLL (Lenstra-Lenstra- Lovász) e Minkowski. Outros resultados incluem caracterizações geométricas de grafos circulantes e de alguns reticulados construídos algebricamente.
Abstract: In this work we approach lattice constructions using properties of algebraic number theory. One focus is on the construction of ideal lattices via cyclotomic fields. Those lattices have been used as an efficient tool for designing coding strategies for the Rayleigh fading channels since it is possible to estimate the product distance and the diversity, parameters which control the error probability transmission for those channels. A special case, due to "shaping gain", is when those lattices are rotations of the n-dimensional integer lattice. We present a new construction of such lattices when n is a power of 2, via the maximal sub-field of the n-cyclotomic field. We also establish conditions for an ideal lattice to be a Zn-lattice using the Minkowski and the LLL (Lenstra-Lenstra-Lovasz) reductions. Other results include geometric characterizations of circulant graphs and of some algebraic lattices.
Doutorado
Doutor em Matemática
32
Backman, Spencer Christopher Foster. "Combinatorial divisor theory for graphs". Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/51908.
Testo completoAbstract (sommario):
Chip-firing is a deceptively simple game played on the vertices of a graph, which was independently discovered in probability theory, poset theory, graph theory, and statistical physics. In recent years, chip-firing has been employed in the development of a theory of divisors on graphs analogous to the classical theory for Riemann surfaces. In particular, Baker and Norin were able to use this set up to prove a combinatorial Riemann-Roch formula, whose classical counterpart is one of the cornerstones of modern algebraic geometry. It is now understood that the relationship between divisor theory for graphs and algebraic curves goes beyond pure analogy, and the primary operation for making this connection precise is tropicalization, a certain type of degeneration which allows us to treat graphs as “combinatorial shadows” of curves. The development of this tropical relationship between graphs and algebraic curves has allowed for beautiful applications of chip-firing to both algebraic geometry and number theory. In this thesis we continue the combinatorial development of divisor theory for graphs. In Chapter 1 we give an overview of the history of chip-firing and its connections to algebraic geometry. In Chapter 2 we describe a reinterpretation of chip-firing in the language of partial graph orientations and apply this setup to give a new proof of the Riemann-Roch formula. We introduce and investigate transfinite chip-firing, and chip-firing with respect to open covers in Chapters 3 and 4 respectively. Chapter 5 represents joint work with Arash Asadi, where we investigate Riemann-Roch theory for directed graphs and arithmetical graphs, the latter of which are a special class of balanced vertex weighted graphs arising naturally in arithmetic geometry.
33
Truman, Paul James. "Hopf-Galois module structure of some tamely ramified extensions". Thesis, University of Exeter, 2009. http://hdl.handle.net/10036/71817.
Testo completoAbstract (sommario):
We study the Hopf-Galois module structure of algebraic integers in some finite extensions of $ p $-adic fields and number fields which are at most tamely ramified. We show that if $ L/K $ is a finite unramified extension of $ p $-adic fields which is Hopf-Galois for some Hopf algebra $ H $ then the ring of algebraic integers $ \OL $ is a free module of rank one over the associated order $ \AH $. If $ H $ is a commutative Hopf algebra, we show that this conclusion remains valid in finite ramified extensions of $ p $-adic fields if $ p $ does not divide the degree of the extension. We prove analogous results for finite abelian Galois extensions of number fields, in particular showing that if $ L/K $ is a finite abelian domestic extension which is Hopf-Galois for some commutative Hopf algebra $ H $ then $ \OL $ is locally free over $ \AH $. We study in greater detail tamely ramified Galois extensions of number fields with Galois group isomorphic to $ C_{p} \times C_{p} $, where $ p $ is a prime number. Byott has enumerated and described all the Hopf-Galois structures admitted by such an extension. We apply the results above to show that $ \OL $ is locally free over $ \AH $ in all of the Hopf-Galois structures, and derive necessary and sufficient conditions for $ \OL $ to be globally free over $ \AH $ in each of the Hopf-Galois structures. In the case $ p = 2 $ we consider the implications of taking $ K = \Q $. In the case that $ p $ is an odd prime we compare the structure of $ \OL $ as a module over $ \AH $ in the various Hopf-Galois structures.
34
Rezola, Nolberto. "Unique Prime Factorization of Ideals in the Ring of Algebraic Integers of an Imaginary Quadratic Number Field". CSUSB ScholarWorks, 2015. https://scholarworks.lib.csusb.edu/etd/205.
Testo completoAbstract (sommario):
The ring of integers is a very interesting ring, it has the amazing property that each of its elements may be expressed uniquely, up to order, as a product of prime elements. Unfortunately, not every ring possesses this property for its elements. The work of mathematicians like Kummer and Dedekind lead to the study of a special type of ring, which we now call a Dedekind domain, where even though unique prime factorization of elements may fail, the ideals of a Dedekind domain still enjoy the property of unique prime factorization into a product of prime ideals, up to order of the factors. This thesis seeks to establish the unique prime ideal factorization of ideals in a special type of Dedekind domain: the ring of algebraic integers of an imaginary quadratic number field.
35
Usatine, Jeremy. "Arithmetical Graphs, Riemann-Roch Structure for Lattices, and the Frobenius Number Problem". Scholarship @ Claremont, 2014. http://scholarship.claremont.edu/hmc_theses/57.
Testo completoAbstract (sommario):
If R is a list of positive integers with greatest common denominator equal to 1, calculating the Frobenius number of R is in general NP-hard. Dino Lorenzini defines the arithmetical graph, which naturally arises in arithmetic geometry, and a notion of genus, the g-number, that in specific cases coincides with the Frobenius number of R. A result of Dino Lorenzini's gives a method for quickly calculating upper bounds for the g-number of arithmetical graphs. We discuss the arithmetic geometry related to arithmetical graphs and present an example of an arithmetical graph that arises in this context. We also discuss the construction for Lorenzini's Riemann-Roch structure and how it relates to the Riemann-Roch theorem for finite graphs shown by Matthew Baker and Serguei Norine.
We then focus on the connection between the Frobenius number and arithmetical graphs. Using the Laplacian of an arithmetical graph and a formulation of chip-firing on the vertices of an arithmetical graph, we show results that can be used to find arithmetical graphs whose g-numbers correspond to the Frobenius number of R. We describe how this can be used to quickly calculate upper bounds for the Frobenius number of R.
36
Tenório, Wanderson [UNESP]. "Reticulados modulares em espaços euclidianos". Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/86492.
Testo completoAbstract (sommario):
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tenorio_w_me_sjrp.pdf: 1508167 bytes, checksum: 36530f0c3764378ac3058a557c3597e5 (MD5)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
O objetivo deste trabalho é apresentar resultados sobre modularidade de reticulados. Mais especificamente, apresentamos as propriedades de um reticulado modular num espaço euclidiano arbitrário e a relação entre as theta séries de reticulados modulares pares e formas modulares. Além disso, apresentamos o estudo de modularidade em reticulados ideais fornecendo condições de existência, construções e caracterização de reticulados ideais modulares para graus especiais em corpos ciclotômicos
The aim of this work is to show results about modularity of lattices. More specifically, we show the properties of a modular lattice in an arbitrary Euclidean space and the relationship between theta series of even modular lattices and modular forms. Moreover, we show the study of modularity in ideal lattices giving existence conditions, constructions and characterization of modular ideal lattices for special levels over cyclotomic fields
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Tenório, Wanderson. "Reticulados modulares em espaços euclidianos /". São José do Rio Preto, 2013. http://hdl.handle.net/11449/86492.
Testo completoAbstract (sommario):
Orientador: Antonio Aparecido de AndradeBanca: Edson Donizete de Carvalho
Banca: Clotilzio Moreira dos Santos
Resumo: O objetivo deste trabalho é apresentar resultados sobre modularidade de reticulados. Mais especificamente, apresentamos as propriedades de um reticulado modular num espaço euclidiano arbitrário e a relação entre as theta séries de reticulados modulares pares e formas modulares. Além disso, apresentamos o estudo de modularidade em reticulados ideais fornecendo condições de existência, construções e caracterização de reticulados ideais modulares para graus especiais em corpos ciclotômicos
Abstract: The aim of this work is to show results about modularity of lattices. More specifically, we show the properties of a modular lattice in an arbitrary Euclidean space and the relationship between theta series of even modular lattices and modular forms. Moreover, we show the study of modularity in ideal lattices giving existence conditions, constructions and characterization of modular ideal lattices for special levels over cyclotomic fields
Mestre
38
Aeal, Wemedh. "K-theory, chamber homology and base change for the p-ADIC groups SL(2), GL(1) and GL(2)". Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/ktheory-chamber-homology-and-base-change-for-the-lowercasepadic-groups-sl2-gl1-and-gl2(974c74a7-83ff-4cb2-bbb8-e15cfbb8e2e1).html.
Testo completoAbstract (sommario):
The thrust of this thesis is to describe base change BC_E/F at the level of chamber homology and K-theory for some p-adic groups, such as SL(2,F), GL(1,F) and GL(2,F). Here F is a non-archimedean local field and E is a Galois extension of F. We have had to master the representation theory of SL(2) and GL(2) including the Langlands parameters. The main result is an explicit computation of the effect of base change on the chamber homology groups, each of which is constructed from cycles. This will have an important connection with the Baum-Connes correspondence for such p-adic groups. This thesis involved the arithmetic of fields such as E and F, geometry of trees, the homology groups and the Weil group W_F.
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Myerson, Simon L. Rydin. "Systems of forms in many variables". Thesis, University of Oxford, 2016. http://ora.ox.ac.uk/objects/uuid:a9932e90-4784-466a-a694-d387c1228533.
Testo completoAbstract (sommario):
We consider systems of polynomial equations and inequalities to be solved in integers. By applying the circle method, when the number of variables is large and the system is geometrically well-behaved we give an asymptotic estimate for the number of solutions of bounded size. In the case of R homogeneous equations having the same degree d, a classic theorem of Birch provides such an estimate provided the number of variables is R(R+1)(d-1)2d-1+R or greater and the system is nonsingular. In many cases this conclusion has been improved, but except in the case of diagonal equations the number of variables needed has always grown quadratically in R. We give a result requiring only d2dR+R variables, obtaining linear growth in R. When d = 2 or 3 we require only that the system be nonsingular; when d<4 we require that the coefficients of the equations belong to a certain explicit Zariski open set. These conditions are satisfied for typical systems of equations, and can in principle be checked algorithmically for any particular system. We also give an asymptotic estimate for the number of solutions to R polynomial inequalities of degree d with real coefficients, in the same number of variables and satisfying the same geometric conditions as in our work on equations. Previously one needed the number of variables to grow super-exponentially in the degree d in order to show that a nontrivial solution exists.
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Silva, Alexsandro BelÃm da. "FamÃlias infinitas de corpos quadrÃticos imaginÃrios". Universidade Federal do CearÃ, 2010. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=5664.
Testo completoAbstract (sommario):
FundaÃÃo de Amparo à Pesquisa do Estado do CearÃCoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior
Seja ℓ > 3 um primo Ãmpar. Sejam So, S+, S_ conjuntos finitos mutuamente disjuntos de primos racionais. Para qualquer nÃmero real suficientemente grande X > 0, baseando-nos em [16], damos neste trabalho, um limite inferior do nÃmero de corpos quadrÃticos imaginÃrios k que satisfazem as seguintes condiÃÃes: o discriminante de k à maior que -X o nÃmero de classe de k à nÃo divisÃvel por ℓ, todo q â So se ramifica, todo q â S+ se decompÃe e todo q â S_ à inerte em k, respectivamente.
Let ℓ > 3 be an odd prime. Let So, S+, S_ be mutually disjoint finite sets of rational primes. For any suficiently large real number X > 0, basing ourselves on [16], we give this paper a lower bound of the number of imaginary quadratic fields k which satisfy the following conditions: the discriminant of k is greater than -X, the class number ok is not divisible by ℓ, every q â So ramifies, every q â S+ splits and every q â S_ is inert in k, respectively.
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Santos, Jefferson Marques. "Altura e equidistribuição de pontos algébricos". Universidade Federal de Goiás, 2017. http://repositorio.bc.ufg.br/tede/handle/tede/7564.
Testo completoAbstract (sommario):
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The concept of roots of a polynomial is quite simple but has several applications. This concept extends more generally to the case of "small" algebraic points sequences in a curve. This dissertation aims to estimate the size of algebraic numbers by means of Weil height. In addition to showing that they are distributed evenly around the unit circle, through Bilu Equidistribution Theorem.
O conceito de raízes de um polinômio é bastante simples mas possui várias aplicações. Este conceito se estende de forma mais geral para o caso de sequências de pontos algébricos “pequenos” em uma curva. Esta dissertação tem por objetivo estimar o tamanho de números algébricos por meio da altura de Weil. Além de mostrar que os mesmos se distribuem uniformemente em torno do círculo unitário, por meio do Teorema de Equidistribuição de Bilu.
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Tyler, Michael Peter. "On the birational section conjecture over function fields". Thesis, University of Exeter, 2017. http://hdl.handle.net/10871/31600.
Testo completoAbstract (sommario):
The birational variant of Grothendieck's section conjecture proposes a characterisation of the rational points of a curve over a finitely generated field over Q in terms of the sections of the absolute Galois group of its function field. While the p-adic version of the birational section conjecture has been proven by Jochen Koenigsmann, and improved upon by Florian Pop, the conjecture in its original form remains very much open. One hopes to deduce the birational section conjecture over number fields from the p-adic version by invoking a local-global principle, but if this is achieved the problem remains to deduce from this that the conjecture holds over all finitely generated fields over Q. This is the problem that we address in this thesis, using an approach which is inspired by a similar result by Mohamed Saïdi concerning the section conjecture for étale fundamental groups. We prove a conditional result which says that, under the condition of finiteness of certain Shafarevich-Tate groups, the birational section conjecture holds over finitely generated fields over Q if it holds over number fields.
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Cox, Robert F. "Case studies of employee participation programs in construction and their effects on absenteeism". Diss., Virginia Tech, 1994. http://hdl.handle.net/10919/40050.
Testo completo
44
Weinstein, Madeleine. "Adinkras and Arithmetical Graphs". Scholarship @ Claremont, 2016. http://scholarship.claremont.edu/hmc_theses/85.
Testo completoAbstract (sommario):
Adinkras and arithmetical graphs have divergent origins. In the spirit of Feynman diagrams, adinkras encode representations of supersymmetry algebras as graphs with additional structures. Arithmetical graphs, on the other hand, arise in algebraic geometry, and give an arithmetical structure to a graph. In this thesis, we will interpret adinkras as arithmetical graphs and see what can be learned.
Our work consists of three main strands. First, we investigate arithmetical structures on the underlying graph of an adinkra in the specific case where the underlying graph is a hypercube. We classify all such arithmetical structures and compute some of the corresponding volumes and linear ranks.
Second, we consider the case of a reduced arithmetical graph structure on the hypercube and explore the wealth of relationships that exist between its linear rank and several notions of genus that appear in the literature on graph theory and adinkras.
Third, we study modifications of the definition of an arithmetical graph that incorporate some of the properties of an adinkra, such as the vertex height assignment or the edge dashing. To this end, we introduce the directed arithmetical graph and the dashed arithmetical graph. We then explore properties of these modifications in an attempt to see if our definitions make sense, answering questions such as whether the volume is still an integer and whether there are still only finitely many arithmetical structures on a given graph.
45
Montes, Jesús. "Polígonos de Newton de orden superior y aplicaciones aritméticas". Doctoral thesis, Universitat de Barcelona, 1999. http://hdl.handle.net/10803/31929.
Testo completoAbstract (sommario):
La teoría algebraica de números tiene sus inicios en los trabajos de Kummer sobre la ecuación de Fermat. En los anillos ciclotómicos deja de ser cierto el teorema fundamental de la aritmética: los elementos descomponen en producto de elementos "primos", pero no de manera única. Kummer, en una intuición genial, apuntó que esta dificultad podía salvarse considerando la existencia de números ideales que permitirían recuperar la unicidad en la descomposición en producto de números ideales primos. Estas ideas las culminó Dedekind en 1878 fundando la teoría de ideales tal como la conocemos hoy en día. Los anillos de enteros de los cuerpos de números son dominios de Dedekind, es decir, todo ideal descompone de manera única en producto de ideales primos.
No obstante, la teoría de Dedekind no es efectiva. Cuando nos enfrentamos a un problema concreto, como por ejemplo resolver una ecuación diofántica, que exige considerar un cuerpo de números “K”, de anillo de enteros “O”, necesitamos resolver en general dos cuestiones fundamentales: (a) Determinar el tipo de descomposición pO = p(e1/) …… p(e/g) de los primos racionales en “K”. (b) Determinar generadores de los ideales P(1). Usualmente querremos computar estos datos a partir de una ecuación definidora del cuerpo K. Este aspecto efectivo lo cubre parcialmente Dedekind, usando ideas de Kummer, permitiendo resolver las dos cuestiones para todos los primos “p” excepto un número finito.
El siguiente paso, extraordinariamente importante tanto desde un punto de vista conceptual como de la efectividad, lo da Rensel, con la introducción de los cuerpos p-ádicos. Esta idea revolucionaria permite "descomponer" los problemas aritméticos globales en una suma de problemas locales, donde se focaliza la atención en los fenómenos que afectan a un primo concreto ”p”. Esta filosofía da como resultado práctico que el problema de la efectividad puede resolverse mediante técnicas locales que comportan esencialmente la factorización de polinomios en cuerpos p-ádicos (que se traduce en la práctica en factorizar módulo una potencia suficientemente alta de p) y la determinación de bases de enteros de órdenes locales. Utilizando distintas variantes de estas ideas se han obtenido diversos algoritmos para hallar la descomposición en producto de ideales primos. Destaquemos los de Pohst-Zassenhaus, Boffgen-Reichert y Buchmann-Lenstra.
El objetivo principal de la memoria es el de desarrollar un nuevo algoritmo, basado en la técnica del polígono de Newton. El polígono de Newton se utilizó en el siglo pasado para estudiar las singularidades de curvas planas. En 1907 Bauer reconvirtió la técnica para su aplicación a cuestiones aritméticas; sus propuestas fueron extensamente ampliadas por Ore, quien en una serie de artículos en los años 20, introduce un concepto más general de polígono, el q)(X)-polígono, que permite tratar el caso en que los factores irreducibles de F(X) no son necesariamente lineales. En la terminología clásica, la aplicación estricta del polígono (Bauer-Ore) es conocida como la "segunda aproximación", mientras que la información extra que obtiene Ore de cada lado se bautizó como la "tercera aproximación" (el teorema de Kummer-Dedekind) era la "primera aproximación". Esas aproximaciones han sido mejoradas y generalizadas por distintos autores; por ejemplo, Ore puso en un contexto más general la segunda aproximación inicial de Bauer, ó Montes-Nart refinaron la tercera aproximación. Ahora bien, los autores clásicos ya eran conscientes de que por mucho que se refinaran esas aproximaciones, siempre quedarían polinomios para los cuales todavía no se obtiene la respuesta definitiva. También intuían que debería ser posible introducir aproximaciones de más alto nivel que permitieran resolver la cuestión para cualquier polinomio en un proceso iterativo finito. Ésa es precisamente la cuestión que resolvemos en la memoria con nuestros polígonos de orden superior.
Pasamos a describir brevemente el contenido de los distintos capítulos de la memoria. En el capítulo 1 se exponen los principales resultados de Ore sobre el polígono de Newton trasladados al contexto de cuerpos locales. Se distinguen cuatro fases distintas, cada una culminando con un resultado clave que denominamos respectivamente teorema del producto (de carácter instrumental), del polígono (segunda aproximación), del polinomio asociado (tercera aproximación) y del índice. El conjunto de estas fases constituye lo que llamamos el nivel 1 ó orden 1. Cada fase marca los distintos obstáculos que será necesario superar en cada nivel con los polígonos de orden superior. Este es el objetivo del segundo capítulo, que constituye el núcleo principal de la memoria.
Dentro del segundo capítulo merecen mención especial las definiciones del polígono y del polinomio asociado en orden r. La definición correcta de "polígono a otro nivel" requiere considerar extensiones adecuadas de la valoración p-ádica al anillo de polinomios, marcadas por datos proporcionados por el polígono de orden anterior. Valoraciones de este tipo fueron introducidas por MacLane también con el propósito de obtener un algoritmo para determinar la descomposición de los primos en cuerpos de números; no obstante, sus métodos no son efectivos. La definición del polinomio asociado en orden r es el obstáculo cuya superación presentó mayores dificultades. En el fondo su construcción se reduce a encontrar "buenos" representantes de ciertas clases residuales módulo las valoraciones que acabamos de mencionar; ahora bien, la elección correcta (es decir, que funcione) de esos representantes pasa por un delicado trabajo con fracciones racionales. Finalmente, el teorema del índice es el resultado clave en el control de la finitud del proceso iterativo.
En el tercer capítulo se describe un proceso de obtención de "representantes optimales" , que permiten recoger toda la información posible que se puede obtener a un nivel determinado antes de verse obligado a pasar al nivel superior. Con esta técnica se obtiene una implementación mucho más ágil del algoritmo que la que se obtendría con una aplicación ciega de los resultados del capítulo 2.
En el cuarto capítulo se usan las técnicas del capítulo 2 para determinar de manera no algorítmica el discriminante absoluto y el tipo de descomposición de los primos en un cuerpo cuártico arbitrario.
46
Gounelas, Frank. "Free curves on varieties". Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:3a7f6dba-fad2-4517-994e-0b51ea311df8.
Testo completoAbstract (sommario):
In this thesis we study various ways in which every two general points on a variety can be connected by curves of a fixed genus, thus mimicking the notion of a rationally connected variety but for arbitrary genus. We assume the existence of a covering family of curves which dominates the product of a variety with itself either by allowing the curves in the family to vary in moduli, or by assuming the family is trivial for some fixed curve of genus g. A suitably free curve will be one with a large unobstructed deformation space, the images of whose deformations can join any number of points on a variety. We prove that, at least in characteristic zero, the existence of such a free curve of higher genus is equivalent to the variety being rationally connected. If one restricts to the case of genus one, similar results can be obtained even allowing the curves in the family to vary in moduli. In later chapters we study algebraic properties of such varieties and discuss attempts to prove the same rational connectedness result in positive characteristic.
47
Souza, Vera Lúcia Graciani de. "Fatoração de inteiros e grupos sobre conicas". [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/306147.
Testo completoAbstract (sommario):
Orientador: Martinho da Costa AraujoDissertação (mestrado profissional) - Universidade Estadual de Campinas. Instituto de Matematica, Estatistica e Computação Cientifica
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Resumo: Este trabalho tem por objetivo fatorar número inteiro utilizando pontos racionais sobre o círculo unitário. Igualmente pretende determinar alguns grupos sobre cônicas. A pesquisa inicia com os conceitos básicos de Álgebra e Teoria dos Números, que fundamentam que o conjunto de pontos racionais sobre o círculo unitário tem uma estrutura de grupo. Desse conjunto é possível estender a idéia de grupo de pontos racionais sobre o círculo para pontos racionais sobre cônicas. Para encontrar os pontos racionais sobre o círculo foi usada uma parametrização do círculo por funções trigonométricas. Para cada ponto sobre o círculo unitário está associado um ângulo com o eixo positivo das abscissas, portanto adicionar pontos sobre o círculo equivale adicionar seus ângulos correspondentes. Com a operação "adição" de pontos sobre o círculo é possível definir uma estrutura de grupo que é utilizada para fatorar números inteiros. Para a cônica, a operação "adição" é determinada algebricamente ao calcular o coeficiente angular da reta que passa por dois pontos dados e o elemento neutro dessa cônica, também justificada geometricamente. No trabalho foram determinados os grupos de pontos racionais sobre cônicas e demonstrado alguns resultados sobre esses grupos usando os resíduos quadráticos e finalizando com a dedução de alguns resultados sobre a soma das coordenadas dos pontos sobre uma cônica.
Abstract: The objective of this paper is to factorize integer number using rational points on the unitary circle. Also, it intends to determinate some groups on the conics. The research begins with the basic concepts of Algebra and Number Theory ensuring that the rational points set on the unitary circle has a structure of group. From this set is possible to extend the idea of rational points on the circle toward rational points on conics. In order to find the rational points on the circle a parametrization by trigonometric function on it was used. For each point on the unitary circle it is associated an angle with abscissa positive axis, therefore adding points on the circle equals to add its corresponding angles. With the operation of "addition" points on the circle it is possible to define a group structure that is used to factorize integer numbers. For the conic, the "addition" operation is algebraically determinated when the angle coeficient of the line is calculated that joins two given points and the neutral element of that conic, which is geometrically justified. In the research the rational points groups on the conics were determined, and some result on these groups using quadratic residues were demonstrated, and it was finalized with the deduction of some results concerning the coordinates sum of points on a conics.
Mestrado
Mestre em Matemática
48
Jorge, Grasiele Cristiane 1983. "Reticulados q-ários e algébricos". [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/306602.
Testo completoAbstract (sommario):
Orientador: Sueli Irene Rodrigues CostaTese (doutorado) - Universidade Estadual de Campinas, Instituto de Matemática, Estatística e Computação Cientifica
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Resumo: O uso de códigos e reticulados em teoria da informação e na "chamada criptografia pós-quântica" vem sendo cada vez mais explorado. Neste trabalho estudamos temas relacionados a estas duas vertentes. A análise de reticulados foi feita via as métricas euclidiana e da soma. Para a métrica euclidiana, estudamos um algoritmo que procura pela treliça mínima de um reticulado com sub-reticulado ortogonal. No caso bidimensional foi possível caracterizar todos os sub-reticulados ortogonais de um reticulado racional qualquer. No estudo de reticulados via métrica da soma, trabalhamos com duas relações entre códigos e reticulados, conhecidas como "Construção A" e "Construção B". Generalizamos a Construção B para uma classe de códigos q-ários... Observação: O resumo, na íntegra, poderá ser visualizado no texto completo da tese digital
Abstract: The use of codes and lattices in Information Theory and in the so-called "Post-quantum Cryptography" has been increasingly explored. In this work we have studied topics related to these two aspects. The analysis of lattices was made via Euclidean and sum metrics. For the Euclidean metric we studied an algorithm that searches for a minimum trellis of a lattice with orthogonal sublattice. In the two-dimensional case it has been possible to characterize all orthogonal sublattices of any rational lattice. In the study of lattices via sum metric, we worked with two relations between codes and lattices, the so-called "Construction A " and "Construction B". We generalized Construction B for the class of q-ary codes...Note: The complete abstract is available with the full electronic document
Doutorado
Matematica
Doutor em Matemática
49
Benedito, Cintya Wink de Oliveira 1985. "Construção de grupos fuchsianos aritméticos provenientes de álgebras dos quatérnios e ordens maximais dos quatérnios associados a reticulados hiperbólicos". [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/261092.
Testo completoAbstract (sommario):
Orientadores: Reginaldo Palazzo Júnior, Cátia Regina de Oliveira Quilles QueirozTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
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Resumo: Na busca por novos sistemas de comunicações muitos trabalhos têm sido realizados com o objetivo de obter constelações de sinais e códigos geometricamente uniformes no plano hiperbólico. Neste contexto, nossa proposta é identificar uma estrutura algébrica e geométrica para que códigos e reticulados possam ser construídos neste espaço. O problema central deste trabalho consiste em construir grupos fuchsianos provenientes de tesselações hiperbólicas regulares {p,q} utilizando diversos tipos de emparelhamentos e identificá-los com álgebras e ordens dos quatérnios, definindo-os assim como aritmético. Desta forma, propomos um algoritmo para construir grupos fuchsianos aritméticos provenientes de tesselações hiperbólicas regulares {p,q} cujo polígono hiperbólico regular gera uma superfície orientada de gênero maior ou igual a dois. Para isso, fornecemos uma condição necessária para que estes grupos possam ser obtidos, esta condição será denominada condição de Fermat devido a sua identificação com os números de Fermat. Através da construção destes grupos, mostramos que existe um isomorfismo entre dois grupos fuchsianos aritméticos provenientes de uma tesselação {p,q} a partir de emparelhamentos diferentes. Além disso, descrevemos alguns dos corpos de números que utilizamos para construir grupos fuchsianos aritméticos, como subcorpos maximais reais de corpos ciclotômicos, a fim de propor uma relação entre os reticulados hiperbólicos e os reticulados euclidianos. Reticulados hiperbólicos completos obtidos através da identificação de grupos fuchsianos com ordens maximais dos quatérnios também são apresentados. Desta forma, obtemos um rotulamento completo dos pontos da constelação de sinal associada
Abstract: In the search for new communications systems many studies have been conducted with the goal of obtaining signal constellations and geometrically uniform codes in the hyperbolic plane. In this context, our proposal is to identify an algebraic and geometric structures for constructing codes and lattices in this space. The central problem of this work is to construct fuchsian groups derived from hyperbolic tessellations {p,q} using different edge-pairings sets and identify them with quaternion algebras and quaternion orders, by setting it as arithmetic. We also propose an algorithm to construct arithmetic fuchsian groups from a tessellation {p,q} whose regular hyperbolic polygon generates an oriented and compact surface with genus greater or equal than 2. For that we provide a necessary condition for these groups to be obtained, this necessary condition is called Fermat condition due to its identification with the Fermat numbers. By the construction of these groups, it is also shown an isomorphism between two arithmetic fuchsian groups derived from a tessellation {p,q} via different edge-pairings sets. Furthermore, we will describe some of the number fields that we use to construct arithmetic fuchsian groups as maximal real subfields of cyclotomic fields in order to propose a relationship between hyperbolic lattices and euclidean lattices. Complete hyperbolic lattices obtained by identifying fuchsian groups with maximal quaternion orders will also be presented. In this way we have a complete labeling of the points of the corresponding signal constellation
Doutorado
Telecomunicações e Telemática
Doutora em Engenharia Elétrica
50
Amorós, Carafí Laia. "Images of Galois representations and p-adic models of Shimura curves". Doctoral thesis, Universitat de Barcelona, 2016. http://hdl.handle.net/10803/471452.
Testo completoAbstract (sommario):
The Langlands program is a vast and unifying network of conjectures that connect the world of automorphic representations of reductive algebraic groups and the world of Galois representations.
These conjectures associate an automorphic representation of a reductive algebraic group to every n-dimensional representation of a Galois group, and the other way around: they attach a Galois representation to any automorphic representation of a reductive algebraic group. Moreover, these correspondences are done in such a way that the automorphic L-functions attached to the two objects coincide.
The theory of modular forms is a field of complex analysis whose main importance lies on its connections and applications to number theory. We will make use, on the one hand, of the arithmetic properties of modular forms to study certain Galois representations and their number theoretic meaning. On the other hand, we will use the geometric meaning of these complex analytic functions to study a natural generalization of modular curves. A modular curve is a geometric object that parametrizes isomorphism classes of elliptic curves together with some additional structure depending on some modular subgroup. The generalization that we will be interested in are the so called Shimura curves. We will be particularly interested in their p-adic models.
In this thesis, we treat two different topics, one in each side of the Langlands program. In the Galois representations' side, we are interested in Galois representations that take values in local Hecke algebras attached to modular forms over finite fields. In the automorphic forms' side, we are interested in Shimura curves: we develop some arithmetic results in definite quaternion algebras and give some results about Mumford curves covering p-adic Shimura curves.