Thesis (Ph. D.)--University of Chicago, 1936. / Vita. "Private edition, distributed by the University of Chicago libraries, Chicago, Illinois." "Reprinted from Travaux de l'Institut mathématique de Tbilissi, vol. 5, 1938."

Thesis (Ph. D.)--University of Chicago, 1918. / "Reprinted from Dickson's History of the Theory of Numbers, Vol. III, Ch. VI. The Carnegie Institution of Washington." Includes bibliographical references and index.

Thesis (Ph.D.)--University of Chicago, 1918. / "Reprinted from Dickson's History of the theory of numbers, vol. III, ch. VI. The Carnegie Institution of Washington."

Thesis (Ph. D.)--University of Chicago, 1918. / "Reprinted from Dickson's History of the Theory of Numbers, Vol. III, Ch. VI. The Carnegie Institution of Washington." Includes bibliographical references and index. Also available on the Internet.

This thesis is focused on the problem of growth and integrability in multi-valued dynamics generated by $SL_2 (\mathbb{Z})$ actions. An important example is given by Markov dynamics on the cubic surface $$x^2+ y^2 +z^2 = 3xyz,$$ generating all the integer solutions of this celebrated Diophantine equation, known as Markov triples. To study the growth problem of Markov numbers we use the binary tree representation. This allows us to define the Lyapunov exponents $\Lambda (x)$ as the function of the paths on this tree, labelled by $x \in \mathbb{R}P^1$. We prove that $\Lambda (x)$ is a $PGL_2 (\mathbb{Z})$-invariant function, which is zero almost everywhere but takes all values in $\left[ 0, \ln \varphi \right]$ (where $\varphi$ denotes the golden ratio). We also show that this function is monotonic, and that its restriction to the Markov-Hurwitz set of most irrational numbers is convex in the Farey parametrisation. We also study the growth problem for integer binary quadratic forms using Conway's topograph representation. It is proven that the corresponding Lyapunov exponent $\Lambda_Q(x) = 2 \Lambda(x)$ except for the paths along the Conway river. Finally, we study the tropical version of the Markov dynamics on the tropical version of the Cayley cubic proposed by Adler and Veselov, and show that it is semi-conjugated to the standard action of $SL_2(\mathbb{Z})$ on a torus. This implies the dynamics is ergodic, with the Lyapunov exponent and entropy given by the logarithm of the spectral radius of the corresponding matrix.

Orientador: Eliris Cristina Rizziolli / Banca: Aldício José Miranda / Banca: Carina Alves / Resumo: Este trabalho trata da classificação geométrica das formas binárias quádricas e cúbicas. Além disto, aplicamos esta classificação ao estudo de máquinas de catástrofes / Abstract: This work make reference of the geometry classification of the two variables quadratic, cubic and quartic forma. Before that, the aplication that classification in study of the catastrophe machines / Mestre

Made available in DSpace on 2014-06-11T19:24:55Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-09-03Bitstream added on 2014-06-13T19:52:48Z : No. of bitstreams: 1 oliveira_arc_me_rcla.pdf: 769124 bytes, checksum: 51f07e82a0a21b5c9270a52d5d3e2500 (MD5) / Universidade Estadual Paulista (UNESP) / Este trabalho trata da classificação geométrica das formas binárias quádricas e cúbicas. Além disto, aplicamos esta classificação ao estudo de máquinas de catástrofes / This work make reference of the geometry classification of the two variables quadratic, cubic and quartic forma. Before that, the aplication that classification in study of the catastrophe machines

Orientador: Itala Maria Loffredo D'Ottaviano / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Filosofia e Ciências Humanas / Made available in DSpace on 2018-08-24T01:21:05Z (GMT). No. of bitstreams: 1 Suguitani_LeandroOliva_D.pdf: 1496205 bytes, checksum: 6197787056972a0020750fa2c72c9cd6 (MD5) Previous issue date: 2013 / Resumo: O resumo poderá ser visualizado no texto completo da tese digital / Abstract: The complete abstract is available with the full electronic document. / Doutorado / Filosofia / Doutor em Filosofia

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-05-29T14:33:20Z No. of bitstreams: 1 williamfredericovasconcellossilva.pdf: 451866 bytes, checksum: bfeb4aa8aa637b66cf493889e77ebca1 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-05-29T19:47:08Z (GMT) No. of bitstreams: 1 williamfredericovasconcellossilva.pdf: 451866 bytes, checksum: bfeb4aa8aa637b66cf493889e77ebca1 (MD5) / Made available in DSpace on 2017-05-29T19:47:08Z (GMT). No. of bitstreams: 1 williamfredericovasconcellossilva.pdf: 451866 bytes, checksum: bfeb4aa8aa637b66cf493889e77ebca1 (MD5) Previous issue date: 2012-07-12 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O principal objetivo do trabalho é estudar a relação entre o espaço de Moduli de feixes de quádricas em Pn e o espaço de Moduli de formas binárias de grau (n + 1). Este estudo foi baseado no artigo (AVRITZER; LANGE, 2000). Em linhas gerais, um espaço de Moduli é uma variedade algébrica que parametriza uma coleção de objetos C, módulo uma relação de equivalência. No nosso caso, C é o conjunto de feixes de quádricas em Pn ou o conjunto de formas binárias de grau (n + 1), e a relação de equivalência é pertencer à mesma órbita pela ação de um grupo G. Para estabelecermos a relação entre esses espaços foi importante considerar o símbolo de Segre que é um invariante dos feixes de quádricas. Além disso, estudamos a forma normal, uma maneira de reescrever o feixe de quádricas, na qual conhecemos facilmente o símbolo de Segre. Estudamos ação de grupos, para podermos classificar um feixe de quádrica e uma forma binária como estável, semi-estável ou instável, e quociente categórico, já que os espaços de Moduli são obtidos através do quociente. / The main objective is to study the relationship between space Moduli of pencil of quadrics, and Moduli space of binary forms. This study was based on article (AVRITZER; LANGE, 2000). In general, a Moduli space is an algebraic variety that parametrizes a collection of objects C, modulo an equivalence relation. In our case, C is the set of pencil of quadrics or set of binary forms of degree (n + 1), and the equivalence relation is to belong to the same orbit by the action of a group G. To establish the relationship between these spaces is important to consider the Segre symbol of which is an invariant of pencils of quadrics. Furthermore, we studied the normal form, a way to rewrite the pencil of quadrics, which easily met the Segre symbol, action of groups, in order to classify a pencil of quadric and a binary form as stable or semistable unstable, and quotient categorical, since the spaces's moduli are obtained by quotient.

L'objet de cette thèse est une description effective des espaces de modules des courbes hyper- elliptiques de genre 3 en caractéristiques positives. En caractéristique nulle ou impaire, on obtient une paramétrisation de ces espaces de modules par l'intermédiaire des algèbres d'invariants pour l'action du groupe spécial linéaire sur les espaces de formes binaires de degré 8, qui sont de type fini. Suite aux travaux de Lercier et Ritzenthaler, les cas des corps de caractéristiques 3, 5 et 7 restaient ouverts. Pour ces derniers, les méthodes classiques de la caractéristique nulle sont inno- pérantes pour l'obtention de générateurs pour les algèbres d'invariants en jeu. Nous nous sommes donc contenté d'exhiber des invariants séparants en caractéristiques 3 et 7. En outre, nos résultats concernant la caractéristique 5 suggèrent l'inadéquation de cette approche pour ce cas. À partir de ces résultats, nous avons pu expliciter la stratification des espaces de modules des courbes hyperelliptiques de genre 3 en caractéristiques 3 et 7 selon les groupes d'automorphismes et implémenté divers algorithmes, dont celui de Mestre, pour la reconstruction d'une courbe à partir de son module, ie la valeur de ses invariants. Pour cette phase de reconstruction, nous nous sommes notamment attaché aux questions arithmétiques, comme l'existence d'une obstruction à être un corps de définition pour le corps de module et, dans le cas contraire, à l'obtention d'un modèle de la courbe sur ce corps minimal. Enfin pour la caractéristique 2, notre approche est différente, dans la mesure où les courbes sont étudiées via leur modèle d'Artin-Schreier. Nous exhibons pour celles-ci des invariants bigradués qui dépendent de la structure arithmétique des points de ramifications des courbes. / The aim of this thesis is to provide an explicite description of the moduli spaces of genus 3 hyperelliptic curves in positive characteristic. Over a field of characteristic zero or odd, a parame- terization of these moduli spaces is given via the algebra of invariants of binary forms of degree 8 under the action of the special linear group. After the work of Lercier and Ritzenthaler, the case of fields of characteristic 3, 5 and 7 are still open. However, in these remaining case, the classical methods in characteristic zero do not work in order to provide generators for these algebra of invariants. Hence we provide only separating invariants in characteristic 3 and 7. Furthermore our results in characteristic 5 show this approach is not suitable. From these results, we describe the stratification of the moduli spaces of genus 3 hyperelliptic curves in characteristic 3 and 7 according to the automorphism groups of the curves and imple- ment algorithms to reconstruct a curve from its invariants. For this reconstruction stage, we paid attention to arithmetic issues, like the obstruction to be a field of definition for the field of moduli. Finally, in the characteristic 2 case, we use a different approach, given that the curves are defined by their Artin-Schreier models. The arithmetic structure of the ramification points of these curves stratify the moduli space in 5 cases and we define in each case invariants that characterize the isomorphism class of hyperelliptic curves.