Dissertations / Theses on the topic 'Géométrie différentielle et algébrique'
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Bardavid, Colas. "Schémas différentiels : approche géométrique et approche fonctoriel." Rennes 1, 2010. http://www.theses.fr/2010REN1S027.
This thesis focuses on the theory - still under construction - of differential schemes. The aim of our work is to provide two new perspectives to this theory. The first perspective is geometric and consists in considering schemes en- dowed with vector fields instead of differential rings. In this context, we define what is a leaf and what is the trajectory of a point. With the help of these tools, we reinvest and generalize some results of differential Galois theory. Similarly, we show that the Carrà Ferro sheaf is the natural sheaf of the space of leaves of a scheme with vector field. It is also this approach that lead us to prove that, in the reduced case, the Kovacic and Keigher sheaves are isomorphic and that they have the same constant as the Carrà Ferro sheaf. The second perspective is functorial, and is based on the notion of scheme due to Toën and Vaquié. We prove that the category of differential schemes in the sense of these authors is equivalent to the category of schemes endowed with a vector field
Hivert, Pascal. "Nappes sous-régulières et équations de certaines compactifications magnifiques." Phd thesis, Université de Versailles-Saint Quentin en Yvelines, 2010. http://tel.archives-ouvertes.fr/tel-00564594.
Sablé, Franck. "Sémantique suppositionnelle et différentielle de l'algèbre discursive, d(S), appliquée aux connecteurs et, mais, si, donc." Paris 4, 2008. http://www.theses.fr/2008PA040183.
The main objective of the thesis is to modelize the conjunctions « et » and « mais ». The result is a unification of the discursive models of the two conjunctions, conservative of the semantics, and having both a property of factorization of the hypothetical conditional independent alternative, seen as an abstraction of concrete, modelezised in a probabilistic Bayesian language, by means of a hypothetical two-dimensionality, represented by « constitutive » hypothesis, direct witnesses of the senses, and « suppositionnal » ones, witnessing by their consequences. On the one hand the concept of supposition is extended to the modelization of « si » and « donc », by a defined plural condition (generalization of particular), and secondly, the Bayesian model is confronted with the differential geometry and with the notion of consistency in a category. A calligraphic model is developed, which aims to unify positional algebra (the words) and compositional algebra (categories). Finally, a strictly multiplicative factorization is proposed through Left self Distributivity (LD-System). Supposition, interpreted as a precise quotient, is dualy qualified as both additive and multiplicative, in order to provide a link between monoid and comonoïd; thus, supposition both creates the space of points and the space of coordinates. The thesis ends with the need to develop the concept of control in linguistic, as a confrontation between « constitutive » and « suppositionnal » hypothesis, and so to build a theory of abduction as a dynamic system
Jardim, da Fonseca Tiago. "Courbes intégrales : transcendance et géométrie." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS515/document.
This thesis is devoted to the study of some questions motivated by Nesterenko's theorem on the algebraic independence of values of Eisenstein series E₂, E₄, E₆. It is divided in two parts.In the first part, comprising the first two chapiters, we generalize the algebraic differential equations satisfied by Eisenstein series that lie in the heart of Nesterenko's method, the Ramanujan equations. These generalizations, called 'higher Ramanujan equations', are obtained geometrically from vector fields naturally defined on certain moduli spaces of abelian varieties. In order to justify the interest of the higher Ramanujan equations in Transcendence Theory, we also show that values of a remarkable particular solution of these equations are related to 'periods' of abelian varieties.In the second part (third chapter), we study Nesterenko's method per se. We establish a geometric statement, containing the theorem of Nesterenko, on the transcendence of values of holomorphic maps from a disk to a quasi-projective variety over $overline{mathbf{Q}}$ defined as integral curves of some vector field. These maps are required to satisfy some integrality property, besides a growth condition and a strong form of Zariski-density that are natural for integral curves of algebraic vector fields
Couvreur, Alain. "Résidus de 2-formes différentielles sur les surfaces algébriques et applications aux codes correcteurs d'erreurs." Phd thesis, Université Paul Sabatier - Toulouse III, 2008. http://tel.archives-ouvertes.fr/tel-00376546.
Louis, Ruben. "Les algèbres supérieures universelles des espaces singuliers et leurs symétries." Electronic Thesis or Diss., Université de Lorraine, 2022. http://www.theses.fr/2022LORR0165.
This thesis breaks into two main parts.1) We show that there is an equivalence of categories between Lie-Rinehart algebras over a commutative algebra O and homotopy equivalence classes of negatively graded acyclic Lie infinity-algebroids. Therefore, this result makes sense of the universal Lie infinity-algebroid of every singular foliation,without any additional assumption, and for Androulidakis-Zambon singular Lie algebroids. This extends to a purely algebraic setting the construction of the universal Q-manifold of a locally real analytic singular foliation. Also, to any ideal I of O preserved by the anchor map of a Lie-Rinehart algebra A, we associate a homotopy equivalence class of negatively graded Lie infinity-algebroids over complexes computing Tor_O(A,O/I). Several explicit examples are given.2) The second part is dedicated to some applications of the results on Lie-Rinehart algebras.a. We associate to any affine variety a universal Lie infinity-algebroid of the Lie-Rinehart algebra of its vector fields. We study the effect of some common operations on affine varieties such as blow-ups, germs at a point, etc.b. We give an interpretation of the blow-up of a singular foliation F in the sense of Omar Mohsen in term of the universal Lie infinity-algebroid of F.c. We introduce the notion of longitudinal vector fields on a graded manifold over a singular foliation, and study their cohomology. We prove that the cohomology groups of the latter vanish.d. We study symmetries of singular foliations through universal Lie infinity-algebroids. More precisely, we prove that a weak symmetry action of a Lie algebra g on a singular foliation F (which is morally an action of g on the leaf space M/F) induces a unique up to homotopy Lie infinity-morphism from g to the Differential Graded Lie Algebra (DGLA) of vector fields on a universal Lie infinity-algebroid of F. We deduce from this general result several geometrical consequences. For instance, we give an example of a Lie algebra action on an affine sub-variety which cannot be extended on the ambient space. Last, we present the notion of tower of bi-submersions over a singular foliation and lift symmetries to those
Jamet, Guillaume. "Obstruction au prolongement des formes différentielles régulières et codimension du lieu singulier." Paris 6, 2000. http://www.theses.fr/2000PA066227.
Allaud, Emmanuel. "Variations de structures de Hodge et systèmes différentiels extérieurs." Toulouse 3, 2002. http://www.theses.fr/2002TOU30123.
Pasillas-Lépine, William. "Systèmes de contact et structures de Goursat : Théorie et application au contrôle des systèmes mécaniques non holonomes." Rouen, 2000. http://www.theses.fr/2000ROUES025.
In the first part of this Ph. D. Thesis, we give necessary and sufficient conditions for a Pfaffian system to be locally equivalent to the canonical contact system on the jet space Jⁿ (R, Rm). Those conditions, which are both geometric and intrinsic, can be checked explicitly and extend in a natural way classical characterizations of certain contact systems obtained by Darboux, Cartan, Bryant and Murray. When our regularity conditions does not hold, we show that Pfaffian system can nevertheless be converted into a normal form that generalizes that introduced by Kumpera and Ruiz in their work on Goursat structures. In the second part, we introduce a new local invariant for Goursat structures. This invariant, called the singularity type, contains an important part of the local geometry of Goursat structures. For example, the growth vector and abnormal curves of any Goursat structure are determined by the singularity type. We also show that any Goursat structure is locally equivalent to the n-trailer system, considered in a neighbourhood of a well-chosen point of its configuration space. In the third part, we apply our results on Goursat structures to the nonholonomic motion planning problem for the n-trailer system in a neighbourhood of a singular configuration. In our study, we also show that any Goursat structure admits locally a pair of generators that span a nilpotent Lie algebra
Pippi, Massimo. "Catégories des singularités, factorisations matricielles et cycles évanescents." Thesis, Toulouse 3, 2020. http://www.theses.fr/2020TOU30049.
The aim of this thesis is to study the dg categories of singularities Sing(X, s) of pairs (X, s), where X is a scheme and s is a global section of some vector bundle over X. Sing(X, s) is defined as the kernel of the dg functor from Sing(X0) to Sing(X) induced by the pushforward along the inclusion of the (derived) zero locus X0 of s in X. In the first part, we restrict ourselves to the case where the vector bundle is trivial. We prove a structure theorem for Sing(X, s) when X = Spec(B) is affine. Roughly, it tells us that every object in Sing(X, s) is represented by a complex of B-modules concentrated in n + 1 consecutive degrees (if s epsilon Bn). By specializing to the case n = 1, we generalize Orlov's theorem, which identifies Sing(X, s) with the dg category of matrix factorizations MF(X, s), to the case where s epsilon OX(X) is not flat. In the second part, we study the l-adic cohomology of Sing(X, s) (as defined by A. Blanc - M. Robalo - B. Toën and G. Vezzosi) when s is a global section of a line bundle. In order to do so, we introduce the l-adic sheaf of monodromy-invariant vanishing cycles. Using a theorem of D. Orlov generalized by J. Burke and M. Walker, we compute the l-adic realization of Sing(Spec(B), (f1 ,..., fn)) for (f1 ,..., fn) epsilon Bn. In the last chapter, we introduce the l-adic sheaves of iterated vanishing cycles of a scheme over a discrete valuation ring of rank 2. We relate one of these l-adic sheaves to the l-adic realization of the dg category of singularities of the fiber over a closed subscheme of the base
Girand, Arnaud. "Équations d'isomonodromie, solutions algébriques et dynamique." Thesis, Rennes 1, 2016. http://www.theses.fr/2016REN1S042/document.
We call isomonodromic deformation any family of logarithmic flat connections over a punctured sphere having the same monodromy representation up to global conjugacy. These objects are parametrised by the solutions of a particular family of partial differential equations called Garnier systems, which are equivalent to the Painlevé VI equations in the four punctured case. The purpose of this thesis is to construct new algebraic solutions of these systems in the five punctured case. First, we give a classification of algebraic isomonodromic deformations obtained by restricting to lines some logarithmic flat connection over the complex projective plane whose singular locus is a quintic curve. We obtain two new families of algebraic solutions of the associated Garnier system. In a second part, we use the fact that any algebraic isomonodromic deformation corresponds to a finite orbit under the mapping class group action on the character variety of the five punctured sphere to obtain new examples of such orbits. We do this by using Katz's middle convolution on representations of free groups. Finally, we give a partial generalisation of this procedure in the case of a twice punctured complex torus
Haiech, Mercedes. "Étude algébrique des systèmes d'équations différentielles polynomiales d'ordre arbitraire." Thesis, Rennes 1, 2020. http://www.theses.fr/2020REN1S035.
In this thesis, several lines of study whose common denominator is differential algebra have been followed to highlight some algebraic properties of systems of differential equations. In one part we have been interested in the overdetermination of ordinary linear differential equation systems and have produced an algorithm to find the generators of such a system.Another part deals with the understanding of the support of partial differential equation solutions using tools from tropical geometry. In a third part, we were interested in the geometrical object described by the set of solutions of an ordinary differential equation and relate the existence of singular essential components for the considered differential equation and the decrease of the dimension of the tangent space of this object calculated at the neighborhood of non-degenerated solutions. In particular, this study involves looking at completion of non-Netherian rings; this situation and the related pathologies are also at the heart of two other parts of this thesis
Rolin, Jean-Philippe. "Géométrie intégrale et invariants d'isotopie." Dijon, 1985. http://www.theses.fr/1985DIJOS035.
Chen, Huayi. "Positivité en géométrie algébrique et en géométrie d'Arakelov : application à l'algébrisation et à l'étude asymptomatique des polygones de Harder-Narasimhan." Palaiseau, Ecole polytechnique, 2006. http://www.theses.fr/2006EPXX0041.
Abril, Bucero Marta. "Matrices de moments, géométrie algébrique réelle et optimisation polynomiale." Thesis, Nice, 2014. http://www.theses.fr/2014NICE4118/document.
The objective of this thesis is to compute the optimum of a polynomial on a closed basic semialgebraic set and the points where this optimum is reached. To achieve this goal we combine border basis method with Lasserre's hierarchy in order to reduce the size of the moment matrices in the SemiDefinite Programming (SDP) problems. In order to verify if the minimum is reached we describe a new criterion to verify the flat extension condition using border basis. Combining these new results we provide a new algorithm which computes the optimum and the minimizers points. We show several experimentations and some applications in different domains which prove the perfomance of the algorithm. Theorethically we also prove the finite convergence of a SDP hierarchie contructed from a Karush-Kuhn-Tucker ideal and its consequences in particular cases. We also solve the particular case where the minimizers are not KKT points using Fritz-John Variety
Ramifidisoa, Lucius. "Propriétés des hypersurfaces centroaffines et équaffines." Valenciennes, 2008. http://ged.univ-valenciennes.fr/nuxeo/site/esupversions/06b1aeb5-5068-4cc7-a092-6512131b6ce2.
The subject of this thesis is in the domain of differential geometry. In this field one studies hypersurfaces M of the (n+1)-dimension vector space. This study can be seen as part of the Erlangen program of Felix Klein: “geometry is the study of the properties which remain invariant under the action of a given group of transformations”. The groups of transformations used in this work are:● the group generated by the linear transformations which preserve volume and the translations. One calls the corresponding geometry the equiaffine geometry or Blaschke geometry; ● the group of all linear transformations. One calls the corresponding geometry the centroaffine geometry. This thesis contains as results in both equiaffine geometry and centroaffine geometry. In equiaffine geometry we obtain a classification of surfaces for which R•( ΔS)=0. In centroaffine geometry we are interested in flat Tchebychev hypersurfaces. We obtain a classification of these hypersurfaces in dimension 3. A similar result in dimension 2 was obtained by Wang
Rittatore, Alvaro. "Monoïdes algébriques et plongements des groupes." Université Joseph Fourier (Grenoble), 1997. http://www.theses.fr/1997GRE10223.
Moniot, Grégoire-Thomas. "Propriétés conformes des entrelacs et quelques autres conséquences de l'étude d'espaces de sphères." Dijon, 2003. http://www.theses.fr/2004DIJOS008.
Saralegui, Martín. "[Dualité entre homologie d'intersection et cohomologie L²]." Lille 1, 1988. http://www.theses.fr/1988LIL10149.
Mestrano, Nicole. "Points rationnels de courbes génériques et de leurs jacobiennes." Nice, 1986. http://www.theses.fr/1986NICE4013.
Comte, Georges. "Densité et images polaires en géométrie sous-analytique." Aix-Marseille 1, 1998. http://www.theses.fr/1998AIX11051.
Burguet, David. "Entropie et complexité locale des systèmes dynamiques différentiables." Phd thesis, Ecole Polytechnique X, 2008. http://tel.archives-ouvertes.fr/tel-00347444.
Dans un deuxième temps, nous reprenons l'approche semi-algébrique de Y. Yomdin et M. Gromov pour contrôler la dynamique locale des applications de classe $C^r$. On présente une preuve complète du lemme algébrique de Gromov, qui est un point clé de la théorie de Yomdin. Aussi nous déduisons de nouvelles applications dynamiques de cette théorie : d'une part nous bornons l'entropie de queue mesurée en fonction de l'exposant de Lyapounov ; d'autre part nous généralisons une formule due à J.Buzzi pour l'entropie k-dimensionnelle d'un produit d'applications de classe $C^{\infty}$.
On s'intéresse enfin à la théorie des extensions symboliques due à M.Boyle et T.Downarowicz pour les applications $C^r$ et affines par morceaux du plan. On exhibe en particulier des exemples de dynamique $C^r$ de l'intervalle ayant une grande entropie d'extension symbolique. Nous donnerons aussi une borne de l'entropie d'extensions symboliques pour les applications affines par morceaux du plan.
Uribe, Vargas Eduardo Ricardo. "Singularités symplectiques et de contact en géométrie différentielle des courbes et des surfaces." Paris 7, 2001. http://www.theses.fr/2001PA077154.
Redou, Pascal. "Géométrie différentielle conforme et représentations dans l'espace des densités tensorielles." Aix-Marseille 1, 2002. http://www.theses.fr/2002AIX11053.
Khemar, Idrisse. "Systèmes intégrables intervenant en géométrie différentielle et en physique mathématique." Phd thesis, Université Paris-Diderot - Paris VII, 2006. http://tel.archives-ouvertes.fr/tel-00277998.
Balacheff, florent. "Inégalités isopérimétriques sur les graphes et applications en géométrie différentielle." Phd thesis, Université Montpellier II - Sciences et Techniques du Languedoc, 2005. http://tel.archives-ouvertes.fr/tel-00010580.
Balacheff, Florent. "Inégalités isopérimétriques sur les graphes et applications en géométrie différentielle." Montpellier 2, 2005. https://tel.archives-ouvertes.fr/tel-00010580.
El, Hilany Boulos. "Géométrie tropicale et systèmes polynomiaux." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAM037/document.
Real polynomial systems are ubiquitous in many areas of pure and applied mathematics. A. Khovanskii provided a fewnomial upper bound on the number of non-degenerate positive solutions of a real polynomial system of $n$ equations in n variables that depends only on the number of monomials appearing in the equations. The latter bound was recently improved by F. Bihan and F. Sottile, but the resulting bound still has room for improvement, even in some simple cases.The aim of this work is to tackle three main problems in Fewnomial theory. Consider a family of real polynomial systems with a given structure (for instance, supports or number of monomials). One problem is to find good upper bounds for their numbers of real (or positive) solutions. Another problem is to construct systems whose numbers of real (or positive) solutions are close to the best known upper bound. When a sharp upper bound is known, what can be said about reaching it?In this thesis, we refine a result by M. Avendaño by proving that the number of real intersection points of a real line with a real plane curve defined by a polynomial with at most t monomials is either infinite or does not exceed 6t -7. Furthermore, we prove that our bound is sharp for t=3 using Grothendieck's real dessins d'enfant. This shows that the maximal number of real intersection points of a real line with a real plane trinomial curve is eleven.We then consider the problem of estimating the maximal number of transversal positive intersection points of a trinomial plane curve and a t-nomial plane curve. T-Y Li, J.-M. Rojas and X. Wang showed that this number is bounded by 2^t-2, and recently P. Koiran, N. Portier and S. Tavenas proved the upper bound 2t^3/3 +5t. We provide the upper bound 3*2^{t-2} - 1 that is sharp for t=3 and is the tightest for t=4,...,9. This is achieved using the notion of real dessins d'enfant. Moreover, we study closely the case t=3 and give a restriction on the supports of systems reaching the sharp bound five.A circuit is a set of n+2 points in mathbb{R}^n that is minimally affinely dependent. It is known that a system supported on a circuit has at most n+1 non-degenerate positive solutions, and that this bound is sharp. We use real dessins d'enfant and Viro's combinatorial patchworking to give a full characterization of circuits supporting polynomial systems with the maximal number of non-degenerate positive solutions.We consider polynomial systems of two equations in two variables with a total of five distinct monomials. This is one of the simplest cases where the sharp upper bound on the number of non-degenerate positive solutions is not known. F. Bihan and F. Sottile proved that this sharp bound is not greater than fifteen. On the other hand, the best examples had only five non-degenerate positive solutions. We consider polynomial systems as before, but defined over the field of real generalized locally convergent Puiseux series. The images by the valuation map of the solutions of such a system are intersection points of two plane tropical curves. Using non-transversal intersections of plane tropical curves, we obtain a construction of a real polynomial system as above having seven non-degenerate positive solutions
Lopez, de Medrano Lucia. "Courbure totale des hypersurfaces algébriques réelles et patchwork." Paris 7, 2007. http://www.theses.fr/2007PA077001.
Masson, Thierry. "Quelques aspects de la géométrie non commutative en liaison avec la géométrie différentielle." Habilitation à diriger des recherches, Université Paris Sud - Paris XI, 2009. http://tel.archives-ouvertes.fr/tel-00445440.
Nguyen, Thi Kim Ngan. "Modules de cycles et classes non ramifiées sur un espace classifiant." Paris 7, 2010. http://www.theses.fr/2010PA077083.
This thesis give an explicit formula for the unramified cohomology H^*_nr(k(W)^G,Q/Z) in terms of the groups AA0(BH,H^*_et(Q/Z)) of partially unramified éléments over a classifying space (H\subsel G), where G is a finite group. More generally, we use the cycle modules defined by Rost and the motivic cohomology defined by Voevodsky. As applications, we give a dual resuit for CH_0 of the compactification of BG in termes of H^AS_0(BH,Z) ( Suslin homology in degre 0) for H\subset G, and we refine and generalise formulas of Bogomolov and Peyre for the unramified cohomology in degre 2 and 3
Chen, Huayi. "Positivité en géométrie algébrique et en géométrie d'Arakelov :application à l'algébrisation et à l'étude asymptotique des polygones deHarder-Narasimhan." Phd thesis, Ecole Polytechnique X, 2006. http://tel.archives-ouvertes.fr/tel-00119162.
Dans la première partie de la thèse, on propose une condition appelée P3 d'un fibré vectoriel sur une varété algébrique projective de dimension au moins 1. On vérifie que cette condition est plus faible que l'amplitude du fibré vectoriel et dans le cadre de la géométrie algébrique complexe, plus faible que la 1-positivité. On montre que si la condition P3 est vérifiée pour le fibré normal du schéma de définition dans un sous-schéma formel, alors on a l'algébricité du sous-schéma formel considéré. Enfin, on donne une application de ce critère à la comparaison de l'équivalence dans un voisinage étale et celle dans un voisinage formel de deux couples de schémas. Une analogue de la condition P3 dans le cadre de la géométrie d'Araklov est aussi étudiée.
Dans la deuxième partie de la thèse, on propose un nouveau point de vu de la filtration de Harder-Narasimhan d'un fibré vectoriel (resp. fibré vectoriel hermitien) sur une courbe projective lisse (resp. le spectre de un anneau des entiers algébriques). On en profite de ramener l'étude de la filtration (ou le polygone) de Harder-Narasimhan à celui de la mesure (borélienne sur R) associée. En combinant cette interprétation avec un argument combinatoire, on démontre que, sous des conditions techniques très faibles, les polygones de Harder-Narasimhan (normalisés) associés à une algèbre graduée de type fini en fibrés vectoriels (hermitiens) convergent uniformément vers une courbe concave sur [0,1], où la démonstration de la partie arithmétique utilise une nouvelle estimation de la pente maximale du produit tensoriel de plusieurs fibrés vectoriels hermitiens développée dans cette thèse.
Nisse, Mounir. "Sur la géométrie et la topologie des amibes et coamibes des variétés algébriques complexes." Paris 6, 2010. http://www.theses.fr/2010PA066131.
Bande, Gianluca. "Formes de contact généralisé, couples de contact et couples contacto-symplectiques." Mulhouse, 2000. http://www.theses.fr/2000MULH0621.
Gorinov, Alexei. "Résolutions coniques des variétés : discriminants et applications à la géométrie algébrique complexe et réelle." Paris 7, 2004. https://tel.archives-ouvertes.fr/tel-00012101.
Bach, Samuel. "Formes quadratiques décalées et déformations." Thesis, Montpellier, 2017. http://www.theses.fr/2017MONTS013/document.
The classical L-theory of a commutative ring is built from the quadratic forms over this ring modulo a lagrangian equivalence relation.We build the derived L-theory from the n-shifted quadratic forms on a derived commutative ring. We show that forms which admit a lagrangian have a standard form. We prove surgery results for this derived L-theory, which allows to reduce shifted quadratic forms to equivalent simpler forms. We compare classical and derived L-theory.We define a derived stack of shifted quadratic forms and a derived stack of lagrangians in a form, which are locally algebraic of finite presentation. We compute tangent complexes and find smooth points. We prove a rigidity result for L-theory : the L-theory of a commutative ring is isomorphic to that of any henselian neighbourhood of this ring.Finally, we define the Clifford algebra of a n-shifted quadratic form, which is a deformation as E_k-algebra of a symmetric algebra. We prove a weakening of the Azumaya property for these algebras, in the case n=0, which we call semi-Azumaya. This property expresses the triviality of the Hochschild homology of the Serre bimodule
Loriot, Sébastien. "Arrangements de cercles sur une sphère : algorithmes et applications aux modèles moléculaires représentés par une union de boules." Dijon, 2008. http://www.theses.fr/2008DIJOS032.
Since the early work of Richard et al. , geometric constructions have been paramount for the description of macromolecules and macro-molecular assemblies. In particular, Voronoï and related constructions have been used to describe the packing properties of atoms, to compute molecular surfaces, to find cavities. This thesis falls in this realm, and after a brief introduction to protein structure, makes four contributions. First, using the sweep line paradigm of Bentley and Ottmann, we present the first effective algorithm able to construct the exact arrangement of circles on a sphere. Moreover, assuming the circles stem from the intersection between spheres, we present a strategy to report the covering list of a face of the arrangement---that is the list of spheres covering it. Along the way, we ascertain the fact that exactness of the arrangement can be achieved with a small computational overhead. Second, we develop the algebraic and geometric primitives required by the sweep algorithm, so as to make it generic and robust. These primitives are integrated in a broader context, namely the CGAL 3D Spherical Kernel. Third, we use the aforementioned machinery to tackle a computational structural biology problem, namely the selection of diverse conformations from a large redundant set. We propose to solve this selection problem by computing representatives maximizing the surface area or the volume of the selection. From a geometric standpoint, these questions can be handled resorting to arrangements of circles and spheres. The validation is carried out along two lines. On the geometric side, we show that our elections match the molecular surface area of selections output by standard strategies but using a smaller number of onformers by one and two orders of magnitude. On the docking side, we show that our selections can significantly improve the results obtained for a flexible-loop docking algorithm. Finally, we discuss the implementation issues and the design choices, in the context of the best practices underlying the development of CGAL
Sevestre, Gabriel. "Géométrie et préquantification des variétés 2-plectiques." Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0142.
An ‘n-plectic manifold’ is a couple formed by a manifold and a closed, non-degenerate differentiable form of degree (n+1). These manifolds generalize the symplectic case (1-plectic) and give a natural framework for studying geometric classical field theories (as well as symplectic manifolds give a natural framework for studying classical mechanics). N-plectic manifolds, already studied since the 70’s, became paramount because of their role in the so-called ‘higher’ approach to differential geometry and topology, subtle structures related to category theory, freshly discovered. In this PhD thesis, we will study almost exclusively 2-plectic manifolds, notably distinguished submanifolds (Lagrangian, co-isotropic…), the dynamic of Hamiltonian systems and symetries of 2-plectic manifolds, as well as their prequantisation
Petitjean, Sylvain. "Géométrie énumérative et contacts de variétés linéaires : application aux graphes d'aspects d'objets courbes." Vandoeuvre-les-Nancy, INPL, 1995. http://docnum.univ-lorraine.fr/public/INPL_T_1995_PETITJEAN_S.pdf.
Polit, Olivier. "Développement d'éléments finis de plaque semi-épaisse et de coque semi-épaisse à double courbure." Paris 6, 1992. http://www.theses.fr/1992PA066584.
Clémençon, Boris. "Extraction des lignes caractéristiques géométriques des surfaces paramétrées et application à la génération de maillages surfaciques." Troyes, 2008. http://www.theses.fr/2008TROY0004.
A major issue for meshing a given analytical surface is to guarantee the accuracy of the underlying geometry. This can be achieved in particular by adapting the mesh to the surface curvature. Without curvature adaptation, parasitic undulations appear in areas where the specified element size is locally large with respect to the minimum radius of curvature : this phenomenon is called aliasing. The classical approach to reduce this phenomenon is to locally decrease the edge size, at the cost of a greater number of elements. We propose to adapt the mesh to the geometry by locating the vertices and the edges along the ridges. These lines are the maxima of the principal curvatures in absolute value along their associated line of curvature. We present methods to characterize and extract the ridges in the case of a parametric surface. Singularities such as umbilics and extremal points are discussed. These vertices and discrete lines form a graph represented by a set of edges. Simplified polygonal lines representing significant ridges are extracted from this graph, interpolated and then integrated as internal curves in the parametric domain. The mesh of this parametric domain including these lines is generated and mapped onto the surface. Examples show that taking ridge lines into account avoids the aliasing without increasing the number of elements, and also reduces the gap between the surface and the mesh
Ruatta, Olivier. "Dualité algébrique, structures et applications." Phd thesis, Université de la Méditerranée - Aix-Marseille II, 2002. http://tel.archives-ouvertes.fr/tel-00002243.
Bay-Rousson, Hugo. "Isomonodromie en théorie de Galois différentielle." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS044.
The first part of this thesis concerns the generalization of a characterization, from a Tannakian point of view, of the exact sequences of affine groupoid schemes, which had been outlined by Esnault-Hai. This characterization was originally developed by Duong-Hai in the case of affine group schemes. This will allow us to prove an exact sequence in differential Galois theory, conjectured by Duong-Hai. In addition, this exact sequence will be used to prove that the Galois group of an inflation is isoconstant. The second part of this thesis is close to the Galois differential theory developed by Cassidy-Singer, then examined in the Tannakian framework by Ovchinnikov, Gillet and Gorchinsky. They introduce the notion of Tannakian differential categories, and prove that the associated Tannakian group is naturally equipped with a connection. By adapting their work to our context, we then show that the Galois group of an inflation naturally has a connection. We show that when this connection is trivial, the Galois group is constant. We will then find an analogue of the fact that the Galois group of an inflation is isoconstant
Gaudron, Éric. "Géométrie des nombres adélique et formes linéaires de logarithmes dans un groupe algébrique commutatif." Habilitation à diriger des recherches, Université de Grenoble, 2009. http://tel.archives-ouvertes.fr/tel-00585976.
Gorinov, Alexey. "Résolutions coniques des variétés discriminants e applications à la géométrie algébrique complexe et réelle." Phd thesis, Université Paris-Diderot - Paris VII, 2004. http://tel.archives-ouvertes.fr/tel-00012101.
résolutions sont parfois appelées coniques.
Dans cette thèse, nous généralisons la méthode des résolutions coniques qui a été proposée par V. A. Vassiliev afin d'étudier la cohomologie des espaces des hypersurfaces projectives lisses complexes. Notre construction se base sur les relations d'inclusion entre les lieux singuliers plutôt qu'entre les systèmes linéaires correspondants. Cela nous permet d'effectuer certains calculs qui semblent être hors de portée de l'approche originelle. Pour illustrer notre méthode, nous calculons la cohomologie rationnelle de l'espace des courbes lisses complexes planes de degré 5, de l'espace des courbes bielliptiques lisses sur une quadrique non dégénérée dans l'espace projectif complexe de dimension 3, ainsi que de l'espace des courbes cubiques réelles lisses planes.
La thèse contient un appendice où l'on démontre le résultat suivant. Supposons que le cercle est muni d'un atlas où tous les changements de cartes sont des homographies ; alors ce cercle borde une surface orientable munie d'un atlas où tous les changements de cartes sont aussi des homographies (à coefficients
complexes cette fois-ci) et sont compatibles dans le sens évident avec les applications de changement de cartes sur le bord. Dans l'appendice, nous montrons également que la classification des structures projectives sur le cercle donnée il y a longtemps par N. Kuiper n'est pas tout à fait correcte, et nous complétons cette classification.
Lo, Bianco Federico. "Dynamique des transformations birationnelles des variétés hyperkähleriennes : feuilletages et fibrations invariantes." Thesis, Rennes 1, 2017. http://www.theses.fr/2017REN1S034/document.
This thesis lies at the interface between algebraic geometry and dynamical systems. The goal is to analyse the dynamical behaviour of automorphisms (or, more generally, of birational transformations) of compact Kaehler manifolds having trivial first Chern class, in particular of hyperkaehler manifolds. I study the existence of geometric structures which are preserved by the dynamics, in particular fibrations and foliations, under some assumptions about the cohomological action of the transformation
Viennot, David. "Géométrie et adiabaticité des systèmes photodynamiques quantiques." Phd thesis, Université de Franche-Comté, 2005. http://tel.archives-ouvertes.fr/tel-00011145.
Jiang, Zhi. "Sur l'application d'albanese des variétés algébriques et le cône nef des produits symétriques de courbes." Université Paris Diderot (Paris 7), 2010. http://www.theses.fr/2010PA077037.
In the first part, I study irregular varieties and in particular, varieties with maximal Albanese dimension. For a general irregular variety X, I give an optimal condition on the plurigenera P_m(X) such that the Albanese map should be subjective and I also obtain a (more restrictive) still optimal condition on P_m(X) such that the Albanese map should be an algebraic fiber space. For a variety X of maximal Albanese dimension with some additional assumptions on P__m(X) and q(X), I describe (birationally) its geometry structure. Then I study morphisms between varieties of maxiaml Albanese dimension. I also make a remark about a work of Chen and Hacon (Pareschi and Popa) to show that for a varieties of maximal Albanese dimension, I6K_XI induces a model of its litaka fibration. In the second part, I study a very concrete problem: the structure of the nef cone of the symmetric product of a generic curve. There is an interesting theorem of Kouvidakis about this problem. I use a degeneration approach to study this problem. The ingredient is an idea due to Ein and Lazarsfeld which they used to study the Seshadri constants of surfaces. I can improve Kouvidakis'result
Marty, Florian. "Des ouverts Zariski et des morphismes lisses en géométrie relative." Toulouse 3, 2009. http://thesesups.ups-tlse.fr/540/.
In this thesis, the author work on the relative scheme theory defined by B. Toën and M. Vaquié in the article "Au dessous de Spec(Z)". More precisely, he studies the properties of Zariski open immersions and smooth morphisms in a relative context, not necessarily additive. The first issue is a description in terms of prime ideals of the Zariski topological space associated to a relative affine scheme. The second issue is a definition of a notion of relative smooth morphism, between monoids, which recover the notion of smooth morphism between rings. The author proves in particular that the affine line is smooth in most relative contexts, as for example the context of scheme over the field with one element (* -> N is smooth) or the context of N-schemes (N ->N[X] is smooth)
Maton, Éric. "Représentation graphique et pensée managériales : le cas de la Harvard Business Review de 1922 à 1999." Palaiseau, Ecole polytechnique, 2007. https://pastel.archives-ouvertes.fr/pastel-00003632.