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Dissertations / Theses on the topic 'Algebraic intersection'
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1
Silberstein, Aaron. "Anabelian Intersection Theory." Thesis, Harvard University, 2012. http://dissertations.umi.com/gsas.harvard:10141.
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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
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Nichols, Margaret E. "Intersection Number of Plane Curves." Oberlin College Honors Theses / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=oberlin1385137385.
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Garay-Lopez, Cristhian Emmanuel. "Tropical intersection theory, and real inflection points of real algebraic curves." Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066364/document.
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Cette thèse est divisée en deux parties principales. D’abord on étudie des relations entre les théories d’intersection en géométrie tropicale et géométrie algébrique. Puis on étudie la question des possibilités pour la distribution de points d’inflexion réels associés à un système linéaire réel défini sur une courbe algébrique réelle lisse. Dans la première partie, nous présentons des nouveaux résultats reliant les théories d’intersection algébrique et tropicale dans une variété algébrique très affine définie sur un corps non-archimédien particulier (dit corps de Mal’cev-Neumann). Le résultat principale concerne l’intersection d’un cycle algébrique de dimension 1 dans une variété à tropicalisation simple avec un diviseur de Cartier. Dans la deuxième partie, nous obtenons d’abord une caractérisation de la répartition des points d’inflexion réels d’un système linéaire complet de degré d>1 sur une courbe elliptique réelle lisse. Puis nous étudions quelques courbes réelles non-hyperelliptiques canoniques de genre 4 dans l’espace projectif de dimension 3. Nous obtenons une formule qui relie le nombre de points de Weierstrass réels d’une telle courbe avec la caractéristique d’Euler-Poincaré d’un certain espace topologique. Finalement, en utilisant la technique du Patchworking (dû à O. Viro), on construit un exemple de courbe réelle, lisse, non-hyperelliptique de genre 4 ayant 30 points de Weierstrass réelsThis thesis is divided in two main parts. First, we study the relationships between intersection theories in tropical and algebraic geometry. Then, we study the question of the possibilities for the distribution of the real inflection points associated to a real linear system defined on a smooth real algebraic curve. In the first part, we present new results linking algebraic and tropical intersection theories over a very-affine algebraic variety defined over a particular non-Archimedean field (known as Mal’cev-Newmann field). The main result concerns the intersection of a one-dimensional algebraic cycle with a Cartier divisor in a variety with simple tropicalization. In the second part, we obtain first a characterization of the distribution of real inflection points associated to a real complete linear system of degree d>1 defined over a smooth real elliptic curve. Then we study some canonical, non-hyperelliptic real algebraic curves of genus 4 in a 3-dimensional projective space. We obtain a formule that relies the amount of real Weierstrass points of such a curve with the Euler-Poincaré characteristic of certain topological space. Finally, using O. Viro’s Patch-working technique, we construct an example of a smooth, non-hyperelliptic real algebraic curve of genus 4 having 30 real Weierstrass points
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Ihringer, Ferdinand [Verfasser]. "Finite geometry intersecting algebraic combinatorics : an investigation of intersection problems related to Erdös-Ko-Rado theorems on Galois geometries with help from algebraic combinatorics / Ferdinand Ihringer." Gießen : Universitätsbibliothek, 2015. http://d-nb.info/1076005918/34.
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Kioulos, Charalambos. "From Flag Manifolds to Severi-Brauer Varieties: Intersection Theory, Algebraic Cycles and Motives." Thesis, Université d'Ottawa / University of Ottawa, 2020. http://hdl.handle.net/10393/40716.
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The study of algebraic varieties originates from the study of smooth manifolds. One
of the focal points is the theory of differential forms and de Rham cohomology. It’s
algebraic counterparts are given by algebraic cycles and Chow groups. Linearizing
and taking the pseudo-abelian envelope of the category of smooth projective varieties,
one obtains the category of pure motives.
In this thesis, we concentrate on studying the pure Chow motives of Severi-Brauer
varieties. This has been a subject of intensive investigation for the past twenty years,
with major contributions done by Karpenko, [Kar1], [Kar2], [Kar3], [Kar4]; Panin,
[Pan1], [Pan2]; Brosnan, [Bro1], [Bro2]; Chernousov, Merkurjev, [Che1], [Che2];
Petrov, Semenov, Zainoulline, [Pet]; Calmès, [Cal]; Nikolenko, [Nik]; Nenashev, [Nen];
Smirnov, [Smi]; Auel, [Aue]; Krashen, [Kra]; and others. The main theorem of the
thesis, presented in sections 4.3 and 4.4, extends the result of Zainoulline et al. in
the paper [Cal] by providing new examples of motivic decompositions of generalized
Severi-Brauer varieties.
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Treisman, Zachary. "Arc spaces and rational curves /." Thesis, Connect to this title online; UW restricted, 2006. http://hdl.handle.net/1773/5780.
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Hilmar, Jan. "Intersection of algebraic plane curves : some results on the (monic) integer transfinite diameter." Thesis, University of Edinburgh, 2008. http://hdl.handle.net/1842/3843.
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Part I discusses the problem of determining the set of intersection points, with corresponding multiplicities, of two algebraic plane curves. We derive an algorithm based on the Euclidean Algorithm for polynomials and show how to use it to find the intersection points of two given curves. We also show that an easy proof of Bézout’s Theorem follows. We then discuss how, for curves with rational coefficients, this algorithm can bemodified to find the intersection points with coordinates expressed in terms of algebraic extensions of the rational numbers. Part II deals with the problem of determining the (monic) integer transfinite diameter of a given real interval. We show how this problem relates to the problem of determining the structure of the spectrum of normalised leading coefficients of polynomials with integer coefficients and all roots in the given interval. We then find dense regions of this spectrum for a number of intervals and discuss algorithms for finding discrete subsets of the spectrum for the interval [0,1]. This leads to an improvement in the known upper bound for the integer transfinite diameter. Finally, we discuss the connection between the infimum of the spectrum and the monic integer transfinite diameter.
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Mitchell, W. P. R. "p-Fold intersection points and their relation with #pi#'s(MU(n))." Thesis, University of Manchester, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.377731.
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Wotzlaw, Lorenz. "Intersection cohomology of hypersurfaces." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2008. http://dx.doi.org/10.18452/15719.
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Bekannte Theoreme von Carlson und Griffiths gestatten es, die Variation von Hodgestrukturen assoziiert zu einer Familie von glatten Hyperflächen sowie das Cupprodukt auf der mittleren Kohomologie explizit zu beschreiben. Wir benutzen M. Saitos Theorie der gemischten Hodgemoduln, um diesen Kalkül auf die Variation der Hodgestruktur der Schnittkohomologie von Familien nodaler Hyperflächen zu verallgemeinern.Well known theorems of Carlson and Griffiths provide an explicit description of the variation of Hodge structures associated to a family of smooth hypersurfaces together with the cupproduct pairing on the middle cohomology. We give a generalization to families of nodal hypersurfaces using M. Saitos theory of mixed Hodge modules.
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Ernstroem, Lars, Shoji Yokura, and yokura@sci kagoshima-u. ac jp. "Bivariant Chern-Schwartz-MacPherson Classes with Values in Chow Groups." ESI preprints, 2000. ftp://ftp.esi.ac.at/pub/Preprints/esi891.ps.
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Gonzalez, Espinoza Luis. "The Knaster-Kuratowski-Mazurkiewicz theorem and abstract convexities." Diss., Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/28640.
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Cohen, Camron Alexander Robey. "CURVING TOWARDS BÉZOUT: AN EXAMINATION OF PLANE CURVES AND THEIR INTERSECTION." Oberlin College Honors Theses / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=oberlin159345184740689.
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Tramel, Rebecca. "New stability conditions on surfaces and new Castelnuovo-type inequalities for curves on complete-intersection surfaces." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/20990.
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Let X be a smooth complex projective variety. In 2002, [Bri07] defined a notion of stability for the objects in Db(X), the bounded derived category of coherent sheaves on X, which generalized the notion of slope stability for vector bundles on curves. There are many nice connections between stability conditions on X and the geometry of the variety. In 2012, [BMT14] gave a conjectural stability condition for threefolds. In the case that X is a complete intersection threefold, the existence of this stability condition would imply a Castelnuovo-type inequality for curves on X. I give a new Castelnuovo-type inequality for curves on complete intersection surfaces of high degree. I then show how this bound would imply the bound conjectured in [BMT14] if a weaker bound could be shown for curves of lower degree. I also construct new stability conditions for surfaces containing a curve C whose self-intersection is negative. I show that these stability conditions lie on a wall of the geometric chamber of Stab(X), the stability manifold of X. I then construct the moduli space Mσ (OX) of σ-semistable objects of class [OX] in K0(X) after wall-crossing.
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Rimmasch, Gretchen. "Complete Tropical Bezout's Theorem and Intersection Theory in the Tropical Projective Plane." Diss., CLICK HERE for online access, 2008. http://contentdm.lib.byu.edu/ETD/image/etd2507.pdf.
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de, Gosson de Varennes Serge. "Multi-oriented Symplectic Geometry and the Extension of Path Intersection Indices." Doctoral thesis, Växjö universitet, Matematiska och systemtekniska institutionen, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:vxu:diva-400.
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Symplectic geometry can be traced back to Lagrange and his work on celestial mechanics and has since then been a very active field in mathematics, partly because of the applications it offers but also because of the beauty of the objects it deals with. I this thesis we begin by the simplest fact of symplectic geometry. We give the definition of a symplectic space and of the symplectic group, Sp(n). A symplectic space is the data of an even-dimensional space and of a form which satisfies a number of properties. Having done this we give a definition of the Lagrangian Grassmannian Lag(n) which consists of all n-dimensional subspaces of the symplectic space on which the symplectic form vanishes. We carefully study the topology of these spaces and their universal coverings. It is of great interest to know how the elements of the Lagrangian Grassmannian intersect each other. A lot of efforts have therefore been made to construct intersection indices for elements of Lag(n). They have gone under many names but have had a sole purpose, namely to give us a way to determine how these elements intersect. We show how these elements are constructed and extend the definition to paths of elements of Lag(n) and Sp(n). We end this thesis by extending the definition of an index defined by Conley and Zehnder bu using the properties of the Leray index. Their index plays a significant role in the theory of periodic Hamiltonian orbit.
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Cheboui, Smail. "Intersection Algébrique sur les surfaces à petits carreaux." Electronic Thesis or Diss., Montpellier, 2021. http://www.theses.fr/2021MONTS006.
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ON étudie la quantité notée Kvol définie par KVol(X,g) = Vol(X,g)*sup_{alpha,beta} frac{Int(alpha,beta)}{l_g (alpha)l_g(beta)} où X est une surface compacte de genre s, Vol(X,g) est le volume (l'aire) de la surface par rapport à la métrique g et alpha, beta deux courbes simples fermées sur la surface X. Les résultats principaux de cette thèse se trouvent dans les chapitres 3 et 4. Dans le chapitre 3 intitulé "Algebraic intersection for translation surfaces in the stratum H(2)" on s'intéresse à la suite des kvol des surfaces L(n,n) et on montre que KVol(L(n,n)) tend vers 2 quand n tend vers l'infini.Dans le chapitre 4 intitulé "Algebraic intersection for translation surfaces in a family of Teichmüller disks" on s'intéresse au Kvol des surfaces appartenant à la strate H(2s-2) qui sont des revêtements ramifiés à n feuillets d'un tore plat. On s'intéresse aussi aux surfaces St(2s-1) et on montre que kvol(St(2s-1))=2s-1 où s est le genre de la surface St(2s-1). On s'intéresse aussi au minimum du Kvol sur le disque de Teichmüller de la surface St(2s-1) qui sera (2s-1)sqrt{frac{143}{144}} et il est atteint aux deux points (pm frac{9}{14}, frac{sqrt{143}}{14})We study the quantity denoted Kvol defined by KVol(X,g) = Vol(X,g)*sup_{alpha,beta} frac{Int(alpha,beta)}{l_g (alpha)l_g(beta)} where X is a compact surface of genus s, Vol(X,g) is the volume (area) of the surface with respect to the metric g and alpha, beta two simple closed curves on the surface X.The main results of this thesis can be found in Chapters 3 and 4. In Chapter 3 titled "Algebraic intersection for translation surfaces in the stratum H(2)" we are interested in the sequence of kvol of surfaces L(n,n) and we provide that KVol(L(n,n)) goes to 2 when n goes to infinity. In Chapter 4 titled "Algebraic intersection for translation surfaces in a family of Teichmüller disks" we are interested in the Kvol for a surfaces belonging to the stratum H(2s-2) wich is an n-fold ramified cover of a flat torus. We are also interested in the surfaces St(2s-1) and we show that kvol(St(2s-1))=2s-1. We are also interested in the minimum of Kvol on the Teichmüller disk of the surface St(2s-1) which will be (2s-1)sqrt {frac {143}{ 144}} and it is achieved at the two points (pm frac{9}{14}, frac{sqrt{143}}{14})
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Poma, Flavia. "Gromov-Witten theory of tame Deligne-Mumford stacks in mixed characteristic." Doctoral thesis, SISSA, 2012. http://hdl.handle.net/20.500.11767/4718.
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We define Gromov-Witten classes and invariants of smooth proper tame Deligne-Mumford stacks of finite presentation over a Dedekind domain. We prove that they are deformation invariants and verify the fundamental axioms. For a smooth proper tame Deligne-Mumford stack over a Dedekind domain, we prove that the invariants of fibers in different characteristics are the same. We show that genus zero Gromov-Witten invariants define a potential which satisfies the WDVV equation and we deduce from this a reconstruction theorem for genus zero Gromov-Witten invariants in arbitrary characteristic.
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Malec, Sara. "Intersection Algebras and Pointed Rational Cones." Digital Archive @ GSU, 2013. http://digitalarchive.gsu.edu/math_diss/14.
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In this dissertation we study the algebraic properties of the intersection algebra of two ideals I and J in a Noetherian ring R. A major part of the dissertation is devoted to the finite generation of these algebras and developing methods of obtaining their generators when the algebra is finitely generated.
We prove that the intersection algebra is a finitely generated R-algebra when R is a Unique Factorization Domain and the two ideals are principal, and use fans of cones to find the algebra generators. This is done in Chapter 2, which concludes with introducing a new class of algebras called fan algebras.
Chapter 3 deals with the intersection algebra of principal monomial ideals in a polynomial ring, where the theory of semigroup rings and toric ideals can be used. A detailed investigation of the intersection algebra of the polynomial ring in one variable is obtained. The intersection algebra in this case is connected to semigroup rings associated to systems of linear diophantine equations with integer coefficients, introduced by Stanley.
In Chapter 4, we present a method for obtaining the generators of the intersection algebra for arbitrary monomial ideals in the polynomial ring.
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Malec, Sara. "Noetherian Filtrations and Finite Intersection Algebras." Digital Archive @ GSU, 2008. http://digitalarchive.gsu.edu/math_theses/55.
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This paper presents the theory of Noetherian filtrations, an important concept in commutative algebra. The paper describes many aspects of the theory of these objects, presenting basic results, examples and applications. In the study of Noetherian filtrations, a few other important concepts are introduced such as Rees algebras, essential powers filtrations, and filtrations on modules. Basic results on these are presented as well. This thesis discusses at length how Noetherian filtrations relate to important constructions in commutative algebra, such as graded rings and modules, dimension theory and associated primes. In addition, the paper presents an original proof of the finiteness of the intersection algebra of principal ideals in a UFD. It concludes by discussing possible applications of this result to other areas of commutative algebra.
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Bonini, Matteo. "Intersections of Algebraic Curves and their link to the weight enumerators of Algebraic-Geometric Codes." Doctoral thesis, Università degli studi di Trento, 2019. https://hdl.handle.net/11572/368573.
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Channel coding is the branch of Information Theory which studies the noise that can occur in data transmitted through a channel. Algebraic Coding Theory is the part of Channel Coding which studies the possibility to detect and correct errors using algebraic and geometric techniques. Nowadays, the best performing linear codes are known to be mostly algebraic geometry codes, also named Goppa codes, which arise from an algebraic curve over a finite field, by the pioneering construction due to V. D. Goppa. The best choices for curves on which Goppa's construction and its variants may provide codes with good parameters are those with many rational points, especially maximal curves attaining the Hasse-Weil upper bound for the number of rational points compared with the genus of the curve. Unfortunately, maximal curves are difficult to find. The best known examples of maximal curves are the Hermitian curve, the Ree curve, the Suzuki curve, the GK curve and the GGS curve.
In the present thesis, we construct and investigate algebraic geometry codes (shortly AG codes), their parameters and automorphism groups.
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Bonini, Matteo. "Intersections of Algebraic Curves and their link to the weight enumerators of Algebraic-Geometric Codes." Doctoral thesis, University of Trento, 2019. http://eprints-phd.biblio.unitn.it/3507/1/PhD_thesis_Bonini.pdf.
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Channel coding is the branch of Information Theory which studies the noise that can occur in data transmitted through a channel. Algebraic Coding Theory is the part of Channel Coding which studies the possibility to detect and correct errors using algebraic and geometric techniques. Nowadays, the best performing linear codes are known to be mostly algebraic geometry codes, also named Goppa codes, which arise from an algebraic curve over a finite field, by the pioneering construction due to V. D. Goppa. The best choices for curves on which Goppa's construction and its variants may provide codes with good parameters are those with many rational points, especially maximal curves attaining the Hasse-Weil upper bound for the number of rational points compared with the genus of the curve. Unfortunately, maximal curves are difficult to find. The best known examples of maximal curves are the Hermitian curve, the Ree curve, the Suzuki curve, the GK curve and the GGS curve.
In the present thesis, we construct and investigate algebraic geometry codes (shortly AG codes), their parameters and automorphism groups.
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Luu, Ba Thang. "Matrix-based implicit representations of algebraic curves and surfaces and applications." Nice, 2011. http://www.theses.fr/2011NICE4035.
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Dans cette thèse, nous introduisons et étudions une nouvelle représentation implicite des hypersurfaces rationnelles plongées dans un espace projectif de dimension arbitraire. Nous illustrons les avantages de cette représentation matricielle en abordant plusieurs problèmes importants intervenant en conception géométrique assistée par ordinateur : les problèmes d’intersection entre deux courbes, entre une courbe et une surface ou bien encore entre deux surfaces, le problème d’appartenance d’une point à une courbe ou une surface, le problème du calcul de la pré-image d’un point donné par une paramétrisation et enfin le problème du calcul des singularités d’une courbe rationnelle. L’approche développée dans ce travail de thèse est basée sur la combinaison de méthodes symboliques et numériques. En effet, une première étape symbolique consiste à transformer le problème considéré en un réseau de matrices. La deuxième étape consiste alors à calculer les valeurs propres généralisées de ce pinceau à l’aide de méthodes numériques. Pour cela, un algorithme d’extraction de la partie régulière d’un pinceau univarié, respectivement bivarié, de matrices non carrées est présenté. Une implémentation de ces travaux dans les systèmes de calcul formel Mathemagix et Maple est présentée en appendice. Le dernier chapitre est consacré » à un algorithme qui, étant donné un ensemble de polynômes univariés ∱₁,…∱s construit un ensemble de polynômes U₁,…, Us dont les degrés sont prescrits, tels que le degré du pgcd (∱₁ + U₁,…, ∱s + Us) est supérieur ou égal à un entier donné sous des hypothèses de généricitéIn this thesis, we introduce and study a new implicit representation of rational curves of arbitrary dimensions and propose an implicit representation of rational hypersurfaces. The, we illustrate the advantages of this matrix representation by addressing several important problems of Computer Aided Geometric Design (CAGD) : the curve/curve, curve/surface and surface/surface intersection problems, the point-on-curve and inversion problems, the computation of singularities of rational curves. We also develop some symbolic/numeric algorithms to manipulate these new representations for example : the algorithm for extracting the regular part of a non square pencil of univariate polynomial matrices and bivariate polynomial matrices. In the appendix of this thesis work we present an implementation of these methods in the computeur algebra systems Mathemagix and Maple. In th last chapter, we describe an algorithm which, given a set of univariate polynomials ∱₁,…∱s returns a set of polynomials U₁,…, Us with prescribed degree-bounds such that the degree of gcd (∱₁ + U₁,…, ∱s + Us) is bounded below by a given degree assuming some genericity hypothesis
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Juteau, Daniel. "Correspondance de Springer modulaire et matrices de décomposition." Phd thesis, Université Paris-Diderot - Paris VII, 2007. http://tel.archives-ouvertes.fr/tel-00355559.
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In 1976, Springer defined a correspondence making a link between the irreducible ordinary (characteristic zero) representations of a Weyl group and the geometry of the associated nilpotent variety. In this thesis, we define a modular Springer correspondence (in positive characteristic), and we show that the decomposition numbers of a Weyl group (for example the symmetric group) are particular cases of decomposition numbers for equivariant perverse sheaves on the nilpotent variety. We calculate explicitly the decomposition numbers associated to the regular and subregular classes, and to the minimal and trivial classes. We determine the correspondence explicitly in the case of the symmetric group, and show that James's row and column removal rule is a consequence of a smooth equivalence of nilpotent singularities obtained by Kraft and Procesi. The first chapter contains generalities about perverse sheaves with Z_l and F_l coefficients.
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Brotbek, Damian. "Variétés projective à fibré cotangent ample." Phd thesis, Université Rennes 1, 2011. http://tel.archives-ouvertes.fr/tel-00677065.
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Nous étudions différentes propriétés d'hyperbolicité pour les variétés intersection complète. Étant donnée une variété intersection complète lisse X ⊂ M dans une variété projective complexe lisse, nous démontrons que si k est plus grand que dim X/ codimM X et si le multidegré de X est suffisamment grand alors il existe sur X des équations différentielles de jets d'ordre k et de degré m pour m suffisamment grand. Ensuite nous étudions une conjecture de O. Debarre : si X ⊂ P^N est l'intersection d'au moins N/2 hypersurfaces génériques de degré suffisamment grand, alors le fibré cotangent de X est ample. Nous donnons différents résultats partiels en direction de cette conjecture. Nous démontrons que si X vérifie les hypothèses de la conjecture alors X est hyperbolique et le fibré cotangent de X est numériquement positif, gros, et ample en dehors d'un lieu de codimension au moins 2. Nous donnons ensuite une stratégie pour calculer explicitement des formes différentielles symétriques sur des variétés intersection complète particulières. Enfin, nous démontrons un théorème d'annulation pour la cohomologie des fibrés de différentielles de jets de Green-Griffiths, généralisant ainsi un théorème de Schneider et un théorème de Diverio. Pour finir, nous étudions la cohomologie des fibrés en droites sur l'hypersurface universelle des diviseurs dans P^1.
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Wakefield, Max. "On the derivation module and apolar algebra of an arrangement of hyperplanes /." view abstract or download file of text, 2006. http://proquest.umi.com/pqdweb?did=1188874511&sid=1&Fmt=2&clientId=11238&RQT=309&VName=PQD.
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Thesis (Ph. D.)--University of Oregon, 2006.Typescript. Includes vita and abstract. Includes bibliographical references (leaves 83-84). Also available for download via the World Wide Web; free to University of Oregon users.
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Tran, Quang Hoa. "Images et fibres des applications rationnelles et algèbres d'éclatement." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066567/document.
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Les applications rationnelles sont des objets fondamentaux en géométrie algébrique. Elles sont utilisées pour décrire certains objets géométriques, tels que la représentation paramétrique d'une variété algébrique rationnelle. Plus récemment, les applications rationnelles sont apparues dans des contextes d'informatique pour l'ingénierie, dans le domaine de la modélisation de formes, en utilisant des méthodes de conception assistée par ordinateur pour les courbes et les surfaces. Des paramétrisations des courbes et des surfaces sont utilisées de manière intensive afin décrire des objets dans la modélisation géométrique, tel que structures des voitures, des avions. Par conséquent, l'étude des applications rationnelles est d'intérêt théorique dans la géométrie algébrique et l'algèbre commutative, et d'une importance pratique dans la modélisation géométrique. Ma thèse étudie les images et les fibres des applications rationnelles en relation avec les équations des algèbres de Rees et des algèbres symétriques. Dans la modélisation géométrique, il est important d'avoir une connaissance détaillée des propriétés géométriques de l'objet et de la représentation paramétrique avec lesquels on travaille. La question de savoir combien de fois le même point est peint (c'est-à-dire, correspond à des valeurs distinctes du paramètre), ne concerne pas seulement la variété elle-même, mais également la paramétrisation. Il est utile pour les applications de déterminer les singularités des paramétrisations. Dans les chapitres 2 et 3, on étudie des fibres d'une application rationnelle de P^m dans P^n qui est génériquement finie sur son image. Une telle application est définie par un ensemble ordonné de (n+1) polynômes homogènes de même degré d. Plus précisément, dans le chapitre 2, nous traiterons le cas des paramétrisations de surfaces rationnelles de P^2 dans P^3, et y donnons une borne quadratique en d pour le nombre de fibres de dimension 1 de la projection canonique de son graphe sur son image. Nous déduisons ce résultat d'une étude de la différence du degré initial entre les puissances ordinaires et les puissances saturées. Dans le chapitre 3, on affine et généralise les résultats sur les fibres du chapitre précédent. Plus généralement, nous établissons une borne linéaire en d pour le nombre de fibres (m-1)-dimensionnelles de la projection canonique de son graphe sur son image, en utilisant des idéaux de mineurs de la matrice jacobienne.Dans le chapitre 4, nous considérons des applications rationnelles dont la source est le produit de deux espaces projectifs.Notre principal objectif est d'étudier les critères de birationalité pour ces applications. Tout d'abord, un critère général est donné en termes du rang d'une couple de matrices connues sous le nom "matrices jacobiennes duales". Ensuite, nous nous concentrons sur des applications rationnelles de P^1 x P^1 vers P^2 en bidegré bas et fournissons de nouveaux critères de birationalité en analysant les syzygies des équations de définition de l'application; en particulier en examinant la dimension de certaines parties bigraduées du module de syzygies. Enfin, les applications de nos résultats au contexte de la modélisation géométrique sont discutées à la fin du chapitreRational maps are fundamental objects in algebraic geometry. They are used to describe some geometric objects,such as parametric representation of rational algebraic varieties. Lately, rational maps appeared in computer-engineering contexts, mostly applied to shape modeling using computer-aided design methods for curves and surfaces. Parameterized algebraic curves and surfaces are used intensively to describe objects in geometric modeling, such as car bodies, airplanes.Therefore, the study of rational maps is of theoretical interest in algebraic geometry and commutative algebra, and of practical importance in geometric modeling. My thesis studies images and fibers of rational maps in relation with the equations of the symmetric and Rees algebras. In geometric modeling, it is of vital importance to have a detailed knowledge of the geometry of the object and of the parametric representation with which one is working. The question of how many times is the same point being painted (i.e., corresponds to distinct values of parameter), depends not only on the variety itself, but also on the parameterization. It is of interest for applications to determine the singularities of the parameterizations. In the chapters 2 and 3, we study the fibers of a rational map from P^m to P^nthat is generically finite onto its image. More precisely, in the second chapter, we will treat the case of parameterizations of algebraic rational surfaces. In this case, we give a quadratic bound in the degree of the defining equations for the number of one-dimensional fibers of the canonical projection of the graph of $\phi$ onto its image,by studying of the difference between the initial degree of ordinary and saturated powers of the base ideal. In the third chapter, we refine and generalize the results on fibers of the previous chapter.More generally, we establish a linear bound in the degree of the defining equations for the number of (m-1)-dimensional fibers of the canonical projection of its graph onto its image, by using ideals of minors of the Jacobian matrix.In the fourth chapter, we consider rational maps whose source is a product of two subvarieties, each one being embedded in a projective space. Our main objective is to investigate birationality criteria for such maps. First, a general criterion is given in terms of the rank of a couple of matrices that came to be known as "Jacobian dual matrices". Then, we focus on rational maps from P^1 x P^1 to P^2 in very low bidegrees and provide new matrix-based birationality criteria by analyzing the syzygies of the defining equations of the map, in particular by looking at the dimension of certain bigraded parts of the syzygy module. Finally, applications of our results to the context of geometric modeling are discussed at the end of the chapter
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Andreja, Tepavčević. "Specijalni elementi mreže i primene." Phd thesis, Univerzitet u Novom Sadu, Prirodno-matematički fakultet u Novom Sadu, 1993. http://dx.doi.org/10.2298/NS19930629TEPAVCEVIC.
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Data je karakterizacija raznih tipova specijalnih elemenata mreže, kao što su kodistributivni, neutralni, skrativi, standardni, izuzetni, neprekidni, beskonačno distributivni i drugi i ti rezultati su primenjeni u strukturnim ispitivanjima algebri, posebno u mrežama kongruencija, podalgebri i slabih kongruencija algebri. Specijalni elementi su posebno proučavani i u bipolumrežama i dobijene su nove teoreme reprezentacije za bipolumreže. Ispitana je kolekcija svih mreža sa istim skupom i-nerazloživih elemenata, pokazano je da je ta kolekcija i sama mreža u odnosu na inkluziju i daju se karakterizacije te mreže. Rešavan je problem prenošenja mrežnih identiteta sa mreže podalgebri i kongruencija na mrežu slabih kongruencija. Proučavane su osobine svojstva preseka kongruencija i svojstva proširenja kongruencija i neke varijante tih svojstava u vezi sa mrežama slabih kongruencija. Date su karakterizacije mreže slabih kongruencija nekih posebnih klasa algebri i varijeteta, kao što su unarne algebra, mreže, grupe, Hamiltonove algebra i druge.A characterization of various types of special elements in lattices: codistributive, neutral, cancellable, standard, exceptional, continuous, infinitely distributive and others are given, and the results are applied in structural investigations in algebras, in particular in lattices of subalgebras, congruences and weak congruences. Special elements are investigated also in bi-semilattices and new representation theorems for bisemilattices are obtained. The collection of all lattices with the same poset of meet-irreducible elements is studied and it is proved that this collection is a lattice under inclusion and characterizations of this lattice is given. A problem of transferability of lattice identities from lattices of subalgebras and congruences to lattices of weak congruencse of algebras is solved. The congruence intersection property and the congruence extension property as well as various alternations of these properties are investigated in connection with weak congruence lattices. Characterizations of weak congruence lattices of special classes of algebras and varieties, as unary algebras, lattices, groups, Hamiltonian algebras and others are given.
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Nemati, Navid. "Syzygies : algebra, combinatorics and geometry." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS284.
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La régularité de Castelnuovo-Mumford est l'un des principaux invariants numériques permettant de mesurer la complexité de la structure des modules gradués de type fini sur des anneaux polynomiaux. Il mesure le degré maximal des générateurs des modules de syzygies. Dans cette thèse, nous étudions la régularité de Castelnuovo-Mumford avec différents points de vue et, dans certaines parties, nous nous concentrons principalement sur les syzygies linéaires. Dans le chapitre 2, nous étudions la régularité des homologies de Koszul et des cycles de Koszul de quotients unidimensionnels. Dans le chapitre 3, nous étudions les propriétés de Lefschetz faibles et fortes d'une classe d'idéaux monomiaux artiniens. Nous donnons, dans certains cas, une réponse affirmative à une conjecture d'Eisenbud, Huneke et Ulrich. Dans les chapitres 4 et 5, nous étudions deux comportements asymptotiques différents de la régularité de Castelnuovo-Mumford. Dans le chapitre 4, nous travaillons sur un quotient d'une algèbre noethérienne standard par suite régulière homogène. Au chapitre 5, nous étudions la régularité des puissances des idéaux monomiaux associés aux graphes en haltère. Dans le chapitre 6, nous travaillons sur des espaces projectifs. Au début de ce chapitre, nous présentons un package pour le logiciel informatique Macaulay2. De plus, nous étudions les cohomologies des "intersections complètes" dans Pnx PmCastelnuovo-Mumford regularity is one of the main numerical invariants that measure the complexity of the structure of homogeneous finitely generated modules over polynomial rings. It measures the maximum degrees of generators of the syzygies. In this thesis we study the Castelnuovo-Mumford regularity with different points of view and, in some parts, we mainly focus on linear syzygies. In Chapter 2 we study the regularity of Koszul homologies and Koszul cycles of one dimensional quotients. In Chapter 3 we study the weak and strong Lefschetz properties of a class of artinain monomial ideals. We show how the structure of the minimal free resolution could force weak or strong Lefschetz properties. In Chapter 4 and 5we study two different asymptotic behavior of Castelnuovo-Mumford regularity. In Chapter 4 we work on a quotient of a standard graded Noetherian algebra by homogeneous regular sequence. It is a celebrated result that the regularity of powers of an ideal in a polynomial ring becomes a linear function. In Chapter 5, we study the regularity of powers of dumbbell graphs. In Chapter 6, we work on product of projective spaces. In the begining of this chapter, we present a package for the computer software Macaulay2. Furthermore, we study the cohomologies of the “complete intersections'' in Pn x Pm
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Warkentin, Matthias. "Fadenmoduln über Ãn und Cluster-Kombinatorik." Master's thesis, Universitätsbibliothek Chemnitz, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-94793.
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Inspired by work of Hubery [Hub] and Fomin, Shapiro and Thurston [FST06] related to cluster algebras, we construct a bijection between certain curves on a cylinder and the string modules over a path algebra of type Ãn. We show that under this bijection irreducible maps and the Auslander-Reiten translation have a geometric interpretation. Furthermore we prove that the dimension of extension groups can be expressed in terms of intersection numbers. Finally we explain the connection to cluster algebras and apply our results to describe the exchange graph in type ÃnAngeregt durch Arbeiten zu Cluster-Algebren von Hubery [Hub] und Fomin, Shapiro und Thurston [FST06] konstruieren wir eine Bijektion zwischen gewissen Kurven auf einem Zylinder und den Fadenmoduln über einer Wege-Algebra vom Typ Ãn. Wir zeigen, daß unter dieser Bijektion sowohl irreduzible Abbildungen als auch die Auslander-Reiten-Verschiebung eine geometrische Interpretation haben. Weiterhin beweisen wir, daß sich die Dimension der Erweiterungsgruppen mittels Anzahlen von Schnittpunkten ausdrücken läßt. Schließlich erklären wir die Verbindung zu Cluster-Algebren und verwenden unsere Ergebnisse um den Austauschgraph im Typ Ãn zu beschreiben
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Smirnov, ILIA. "Smooth Complete Intersections with Positive-Definite Intersection Form." Thesis, 2012. http://hdl.handle.net/1974/7602.
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We classify the smooth complete intersections with positive-definite intersection form on their middle cohomology. There are two families. The first family are quadric hypersurfaces in P(4k+1) with k a positive integer. The middle cohomology is always of rank two and the intersection lattice corresponds to the identity matrix. The second family are complete intersections of two quadrics in P(4k+2) (k a positive integer). Here the intersection lattices are the Gamma(4(k+1)) lattices; in particular, the intersection lattice of a smooth complete intersection of two quadrics in P(6) is the famous E8 lattice.Thesis (Master, Mathematics & Statistics) -- Queen's University, 2012-10-15 13:19:42.654
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Tzeng, Uen-Jiun, and 曾溫鈞. "Computing Intersection of Algebraic Surfaces." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/86921541576533980666.
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碩士國立交通大學
資訊工程研究所
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The evaluation of surface intersections is a recurring operation in geometric and solid modeling. Since algebraic surface have recently become more important, how to efficiently, accurately, and robustly compute the intersection between two algebraic surfaces is a crucial problem. We propose in this thesis an algorithm for computing the intersection of two algebraic surfaces, emphasizing on the issues of robustness and singularities resolution. The algorithm consists of three steps. In the first step, the surface intersection is mapped to a planar curve, say h(x,y)=0, by the monoid computation. The mapping of the surface intersection to a planar curve is advantageous since with the planar curve the singularities can be resolved completely by quadratic transformations. The second step is devoted to the derivation of starting points on each curve component. Loop detection is performed to locate the critical points of the intersection between z=0 and z=h(x,y). Based on the critical points, the (x, y)-space is subdivided selectively and the starting points are obtained as the intersection of the grid boundary and h(x,y)=0. Since the mapping is birational, the starting points on h(x,y)=0 are starting points on the corresponding intersection component. Finally, in the third step, each intersection component is traced from a starting point. The tracing is switched to the tracing of h(x,y)=0 whenever a singularity is encountered, and it is resumed after the singularity is safely passed. The proposed algorithm is able to detect all intersection components and to resolve the singularities completely and systematically. This is achieved at the cost of monoid computations, especially for surfaces of high degree. In the thesis, we also address the implementation issues and experimental results.
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Tamvakis, Haralampos. "Arithmetic intersection theory on flag varieties /." 1997. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:9729873.
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Mouroukos, Evangelos. "Cohomological connectivity and applications to algebraic cycles /." 1999. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:9934095.
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Li, Qirui. "An intersection number formula for CM-cycles in Lubin-Tate spaces." Thesis, 2018. https://doi.org/10.7916/D8KS880K.
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We give an explicit formula for the arithmetic intersection number of CM cycles on Lubin-Tate spaces for all levels. We prove our formula by formulating the intersection number on the infinite level. Our CM cycles are constructed by choosing two separable quadratic extensions K1, K2/F of non-Archimedean local fields F . Our formula works for all cases, K1 and K2 can be either the same or different, ramify or unramified. As applications, this formula translate the linear Arithmetic Fundamental Lemma (linear AFL) into a comparison of integrals. This formula can also be used to recover Gross and Keating’s result on lifting endomorphism of formal modules.
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Field, Rebecca. "On the Chow ring of the classifying space BSO (2n, C) /." 2000. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:9978023.
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Sun, Chia-Liang. "The intersection of closure of global points of a semi-abelian variety with a product of local points of its subvarieties." Thesis, 2011. http://hdl.handle.net/2152/ETD-UT-2011-05-2793.
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This thesis consists of three chapters. Chapter 1 explains how the research problems considered in this thesis fit into the investigation of local-global principle in the diophantine geometry, as well as gives a unified sketch of the proofs of the two main results in this thesis. Chapter 2 establishes a similar conclusion to Theorem B of a paper by Poonen and Voloch in another settings. Chapter 3 relates to the object considered in the main result of Chapter 2 to an old conjecture proposed by Skolem and solves some cases of its analog.text
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Blondin, Michael. "Complexité raffinée du problème d'intersection d'automates." Thèse, 2012. http://hdl.handle.net/1866/8440.
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Le problème d'intersection d'automates consiste à vérifier si plusieurs automates finis déterministes acceptent un mot en commun. Celui-ci est connu PSPACE-complet (resp. NL-complet) lorsque le nombre d'automates n'est pas borné (resp. borné par une constante).
Dans ce mémoire, nous étudions la complexité du problème d'intersection d'automates pour plusieurs types de langages et d'automates tels les langages unaires, les automates à groupe (abélien), les langages commutatifs et les langages finis.
Nous considérons plus particulièrement le cas où chacun des automates possède au plus un ou deux états finaux. Ces restrictions permettent d'établir des liens avec certains problèmes algébriques et d'obtenir une classification intéressante de problèmes d'intersection d'automates à l'intérieur de la classe P. Nous terminons notre étude en considérant brièvement le cas où le nombre d'automates est fixé.The automata non emptiness intersection problem is to determine whether several deterministic finite automata accept a word in common. It is known to be PSPACE-complete (resp. NL-complete) whenever the number of automata is not bounded (resp. bounded by a constant). In this work, we study the complexity of the automata intersection problem for several types of languages and automata such as unary languages, (abelian) group automata, commutative languages and finite languages. We raise the issue of limiting the number of final states to at most two in the automata involved. This way, we obtain relationships with some algebraic problems and an interesting classification of automata intersection problems inside the class P. Finally, we briefly consider the bounded version of the automata intersection problem.
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Stevenson, Gregory Steuart Douglas. "Tensor actions and locally complete intersections." Phd thesis, 2011. http://hdl.handle.net/1885/149741.
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We introduce a relative version of Balmer's tensor triangular geometry by considering the action of a tensor triangulated category on another triangulated category. Several of Balmer's results are extended to this relative setting giving rise to, among other things, a theory of supports for objects of a category upon which a tensor triangulated category acts. In the case that a rigidly-compactly generated tensor triangulated category acts on a compactly generated category we describe a version of the local- to-global principle of Benson, Iyengar, and Krause, and a relative version of the telescope conjecture. We prove the local-to-global principle holds quite generally which is new even in the case that a tensor triangulated category acts on itself as in Balmer's theory. We are also able to give sufficient conditions for the relative telescope conjecture to hold. As an application we study the stable injective category of a noetherian separated scheme X, as introduced by Krause, in terms of an action of the derived category D(X). We give a complete classification of the localizing subcategories of this category in the case that X is the spectrum of a hypersurface ring and prove that the telescope conjecture holds. Our methods allow us to extend these results, suitably modified, to certain complete intersection schemes of arbitrary codimension.
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Bhargava, Sandeep. "Realizations of BC(r)-graded intersection matrix algebras with grading subalgebras of type B(r), r greater than or equal to 3 /." 2008. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:NR45986.
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Thesis (Ph.D.)--York University, 2008. Graduate Programme in Mathematics and Statistics.Typescript. Includes bibliographical references (leaves 275-278). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:NR45986
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Staic, Mihai D. "Quantum groups at intersection between algebra and geometry." 2007. http://proquest.umi.com/pqdweb?did=1331403881&sid=12&Fmt=2&clientId=39334&RQT=309&VName=PQD.
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Thesis (Ph.D.)--State University of New York at Buffalo, 2007.Title from PDF title page (viewed on Nov. 20, 2007) Available through UMI ProQuest Digital Dissertations. Thesis adviser: Schack, Samuel D. Includes bibliographical references.
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Tuncer, Serhan. "Representability of Algebraic CHOW Groups of Complex Projective Complete Intersections and Applications to Motives." Phd thesis, 2010. http://hdl.handle.net/10048/1651.
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In 1990 James D. Lewis made a conjecture on the representability of algebraic Chow groups of projective algebraic manifolds. We prove that his conjecture holds for smooth complex complete intersections satisfying a numerical condition and consider some applications to motives.Mathematics
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Diaz, Humberto Antonio. "Aspects of Motives: Finite-dimensionality, Chow-Kunneth Decompositions and Intersections of Cycles." Diss., 2016. http://hdl.handle.net/10161/12201.
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This thesis analyzes the Chow motives of 3 types of smooth projective varieties: the desingularized elliptic self fiber product, the Fano surface of lines on a cubic threefold and an ample hypersurface of an Abelian variety. For the desingularized elliptic self fiber product, we use an isotypic decomposition of the motive to deduce the Murre conjectures. We also prove a result about the intersection product. For the Fano surface of lines, we prove the finite-dimensionality of the Chow motive. Finally, we prove that an ample hypersurface on an Abelian variety possesses a Chow-Kunneth decomposition for which a motivic version of the Lefschetz hyperplane theorem holds.
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Lávička, Tomáš. "Klasifikace (in)finitárních logik." Master's thesis, 2015. http://www.nusl.cz/ntk/nusl-350171.
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In this master thesis we investigate completeness theorems in the framework of abstract algebraic logic. Our main interest lies in the completeness with respect to the so called relatively (finitely) subdirectly irreducible models. Notable part of the presented theory concerns the difference between finitary and infinitary logical systems. We focus on the well-known fact that the completeness theorem with respect to relatively (finitely) subdirectly irreducible models can be proven in general for all finitary logics and we discuss the possible of generalizing this theorem even to infinitary logics. We show that there are two interesting inter- mediate properties between this completeness and finitarity, namely (completely) intersection-prime extension properties. Based on these notions we define five classes of logics and propose a new hierarchy of finitary and infinitary logics. As a main contribution of this dissertation we present an example of a logic separat- ing some of these classes. Keywords: Abstract algebraic logic, completeness, relatively (finitely) sub- directly irreducible models, RSI-completeness, RFSI-completeness, (completely) intersection-prime extension property, IPEP, CIPEP.
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(9183356), Tan T. Dang. "Topics on the Cohen-Macaulay Property of Rees algebras and the Gorenstein linkage class of a complete intersection." Thesis, 2020.
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We study the Cohen-Macaulay property of Rees algebras of modules of Kähler differentials. When the module of differentials has projective dimension one, it is known that condition $F_1$ is sufficient for the Rees algebra to be Cohen-Macaulay. The converse was proved if the module of differentials is already $F_0$. We weaken the condition $F_0$ globally by assuming some homogeneity condition.We are also interested in the defining ideal of the Rees algebra of a Jacobian module. If the Jacobian module is an ideal, we prove a formula for computing the defining ideal. Using the formula, we give an explicit description of the defining ideal in the monomial case. From there, we characterize the Cohen-Macaulay property of the Rees algebra.
In the last chapter, we study Gorenstein linkage mostly in the graded case. In particular, we give an explicit example of a class of monomial ideals that are in the homogeneous Gorenstein linkage class of a complete intersection. To do so, we prove a Gorenstein double linkage construction that is analogous to Gorenstein biliaison.
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Kabiraj, Arpan. "Goldman Bracket : Center, Geometric Intersection Number & Length Equivalent Curves." Thesis, 2016. http://etd.iisc.ac.in/handle/2005/2838.
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Goldman [Gol86] introduced a Lie algebra structure on the free vector space generated by the free homotopy classes of oriented closed curves in any orientable surface F . This Lie bracket is known as the Goldman bracket and the Lie algebra is known as the Goldman Lie algebra. In this dissertation, we compute the center of the Goldman Lie algebra for any hyperbolic surface of finite type. We use hyperbolic geometry and geometric group theory to prove our theorems. We show that for any hyperbolic surface of finite type, the center of the Goldman Lie algebra is generated by closed curves which are either homotopically trivial or homotopic to boundary components or punctures.
We use these results to identify the quotient of the Goldman Lie algebra of a non-closed surface by its center as a sub-algebra of the first Hochschild cohomology of the fundamental group.
Using hyperbolic geometry, we prove a special case of a theorem of Chas [Cha10], namely, the geometric intersection number between two simple closed geodesics is the same as the number of terms (counted with multiplicity) in the Goldman bracket between them.
We also construct infinitely many pairs of length equivalent curves in any hyperbolic surface F of finite type. Our construction shows that given a self- intersecting geodesic x of F and any self-intersection point P of x, we get a sequence of such pairs.
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Kabiraj, Arpan. "Goldman Bracket : Center, Geometric Intersection Number & Length Equivalent Curves." Thesis, 2016. http://etd.iisc.ernet.in/handle/2005/2838.
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Goldman [Gol86] introduced a Lie algebra structure on the free vector space generated by the free homotopy classes of oriented closed curves in any orientable surface F . This Lie bracket is known as the Goldman bracket and the Lie algebra is known as the Goldman Lie algebra. In this dissertation, we compute the center of the Goldman Lie algebra for any hyperbolic surface of finite type. We use hyperbolic geometry and geometric group theory to prove our theorems. We show that for any hyperbolic surface of finite type, the center of the Goldman Lie algebra is generated by closed curves which are either homotopically trivial or homotopic to boundary components or punctures.
We use these results to identify the quotient of the Goldman Lie algebra of a non-closed surface by its center as a sub-algebra of the first Hochschild cohomology of the fundamental group.
Using hyperbolic geometry, we prove a special case of a theorem of Chas [Cha10], namely, the geometric intersection number between two simple closed geodesics is the same as the number of terms (counted with multiplicity) in the Goldman bracket between them.
We also construct infinitely many pairs of length equivalent curves in any hyperbolic surface F of finite type. Our construction shows that given a self- intersecting geodesic x of F and any self-intersection point P of x, we get a sequence of such pairs.
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Zeman, Peter. "Algebraické, strukturální a výpočetní vlastnosti geometrických reprezentací grafů." Master's thesis, 2016. http://www.nusl.cz/ntk/nusl-352783.
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Title: Algebraic, Structural and Complexity Aspects of Geometric Representations of Graphs Author: Peter Zeman Department: Computer Science Institute Supervisor: RNDr. Pavel Klavík Supervisor's e-mail: klavik@iuuk.mff.cuni.cz Keywords: automorphism groups, interval graphs, circle graphs, comparability graphs, H-graphs, recognition, dominating set, graph isomorphism, maximum clique, coloring Abstract: We study symmetries of geometrically represented graphs. We describe a tech- nique to determine the automorphism group of a geometrically represented graph, by understanding the structure of the induced action on all geometric representations. We prove that interval graphs have the same automorphism groups as trees, and for a given interval graph, we construct a tree with the same automorphism group which answers a question of Hanlon [Trans. Amer. Math. Soc 272(2), 1982]. For permutation and circle graphs, we give an inductive characterization by semidirect and wreath prod- ucts. We also prove that every abstract group can be realized by the automorphism group of a comparability graph/poset of the dimension at most four. We also study H-graphs, introduced by Biró, Hujter, and Tuza in 1992. Those are intersection graphs of connected subgraphs of a subdivision of a graph H. This thesis is the first comprehensive...
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Zhao, Wenhua. "Generalizations of two-dimensional conformal field theory : some results on jacobians and intersection numbers /." 2000. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:9965182.
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Koonz, Jennifer. "Properties of singular schubert varieties." 2013. https://scholarworks.umass.edu/dissertations/AAI3603107.
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This thesis deals with the study of Schubert varieties, which are subsets of flag varieties indexed by elements of Weyl groups. We start by defining Lascoux elements in the Hecke algebra, and showing that they coincide with the Kazhdan-Lusztig basis elements in certain cases. We then construct a resolution (Zw, π) of the Schubert variety Xw for which Rπ*([special characters omitted][ℓ(w)]) is a sheaf on Xw whose expression in the Hecke algebra is closely related to the Lascoux element. We also define two new polynomials which coincide with the intersection cohomology Poincar´e polynomial in certain cases. In the final chapter, we discuss some interesting combinatorial results concerning Bell and Catalan numbers which arose throughout the course of this work.
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Le, Van Dinh. "The broken circuit complex and the Orlik - Terao algebra of a hyperplane arrangement." Doctoral thesis, 2016. https://repositorium.ub.uni-osnabrueck.de/handle/urn:nbn:de:gbv:700-2016021714257.
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My thesis is mostly concerned with algebraic and combinatorial aspects of the
theory of hyperplane arrangements. More specifically, I study the Orlik-Terao algebra of a hyperplane arrangement and the broken circuit complex of a matroid. The Orlik-Terao algebra is a useful tool for studying hyperplane arrangements, especially for characterizing some non-combinatorial properties. The broken circuit complex, on the one hand, is closely related to the Orlik-Terao algebra, and on the other hand, plays a crucial role in the study of many combinatorial problem: the coefficients of the characteristic polynomial of a matroid are encoded in the f-vector of the broken circuit complex of the matroid. Among main results of the thesis are characterizations of the complete intersection and Gorenstein properties of the broken circuit complex and the Orlik-Terao algebra. I also study the h-vector of the broken circuit complex of a series-parallel network and relate certain entries of that vector to ear decompositions of the network. An application of the Orlik-Terao algebra in studying the relation space of a hyperplane arrangement is also included in the thesis.