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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Combinatoire bijective des permutations et nombres de Genocchi / Bijective combinatorics of permutations and Genocchi numbers

Bigeni, Ange 24 November 2015 (has links)
Cette thèse a pour contexte la combinatoire énumérative et décrit la construction de plusieurs bijections entre modèles combinatoires connus ou nouveaux de suites d'entiers et polynômes, plus particulièrement celle des nombres de Genocchi (et de leurs extensions, les polynômes de Gandhi) qui interviennent dans diverses branches des mathématiques et dont les propriétés combinatoires sont de ce fait activement étudiées, et celles de polynômes q-eulériens associés aux quatre statistiques fondamentales de MacMahon sur les permutations ainsi qu'à des statistiques analogues. On commence par définir les permutations de Dumont normalisées, un modèle combinatoire des nombres de Genocchi médians normalisés q-étendus, notés ¯cn(q) et définis par Han et Zeng, puis l'on construit une première bijection entre ce modèle et l'ensemble des configurations de Dellac, autre interprétation combinatoire de ¯cn(q) mise en évidence par Feigin dans le contexte de la géométrie des grassmanniennes de carquois. En s'appuyant sur la théorie des fractions continues de Flajolet, on en construit finalement un troisième modèle combinatoire à travers les histoires de Dellac, que l'on relie aux premiers modèles sus-cités au moyen d'une seconde bijection. On s'intéresse ensuite à la classe combinatoire des k-formes irréductibles définies par Hivert et Mallet dans l'étude des k-fonctions de Schur, et qui faisaient l'objet d'une conjecture supposant que les polynômes de Gandhi sont générés par les k-formes irréductibles selon la statistique des k-sites libres. On construit une bijection entre les k-formes irréductibles et les pistolets surjectifs de hauteur k − 1 (connus pour générer les polynômes de Gandhi selon la statistique des points fixes) envoyant les k-sites libres des premières sur les points fixes des seconds, démontrant de ce fait la conjecture. Enfin, on établit une nouvelle identité combinatoire entre deux polynômes q-eulériens définis par des statistiques eulériennes et mahoniennes sur l'ensemble des permutations d'un ensemble fini, au moyen d'une dernière bijection sur les permutations, qui envoie une suite finie de statistiques sur une autre / This work is set in the context of enumerative combinatorics and constructs several statistic-preserving bijections between known or new combinatorial models of sequences of integers or polynomials, espacially the sequence of Genocchi numbers (and their extensions, the Gandhi polynomials) which appear in numerous mathematical theories and whose combinatorial properties are consequently intensively studied, and two sequences of q-Eulerian polynomials associated with the four fundamental statistics on permutations studied by MacMahon, and with analog statistics. First of all, we define normalized Dumont permutations, a combinatorial model of the q-extended normalized median Genocchi numbers ¯cn(q) introduced by Han and Zeng, and we build a bijection between the latter model and the set of Dellac configurations, which have been proved by Feigin to generate ¯cn(q) by using the geometry of quiver Grassmannians. Then, in order to answer a question raised by the theory of continued fractions of Flajolet, we define a new combinatorial model of ¯cn(q), the set of Dellac histories, and we relate them with the previous combinatorial models through a second statistic-preserving bijection. Afterwards, we study the set of irreducible k-shapes defined by Hivert and Mallet in the topic of k-Schur functions, which have been conjectured to generate the Gandhi polynomials with respect to the statistic of free ksites. We construct a statistic-preserving bijection between the irreducible k-shapes and the surjective pistols of height k−1 (well-known combinatorial interpretation of the Gandhi polynomials with respect to the fixed points statistic) mapping the free k-sites to the fixed points, thence proving the conjecture. Finally, we prove a new combinatorial identity between two eulerian polynomials defined on the set of permutations thanks to Eulerian and Mahonian statistics, by constructing a bijection on the permutations, which maps a finite sequence of statistics on another
2

Field Theoretic Lagrangian From Off-shell Supermultiplet Gauge Quotients

Katona, Gregory 01 January 2013 (has links)
Recent efforts to classify off-shell representations of supersymmetry without a central charge have focused upon directed, supermultiplet graphs of hypercubic topology known as Adinkras. These encodings of Super Poincare algebras, depict every generator of a chosen supersymmetry as a node-pair transformtion between fermionic bosonic component fields. This research thesis is a culmination of investigating novel diagrammatic sums of gauge-quotients by supersymmetric images of other Adinkras, and the correlated building of field theoretic worldline Lagrangians to accommodate both classical and quantum venues. We find Ref [40], that such gauge quotients do not yield other stand alone or "proper" Adinkras as afore sighted, nor can they be decomposed into supermultiplet sums, but are rather a connected "Adinkraic network". Their iteration, analogous to Weyl's construction for producing all finite-dimensional unitary representations in Lie algebras, sets off chains of algebraic paradigms in discrete-graph and continuous-field variables, the links of which feature distinct, supersymmetric Lagrangian templates. Collectively, these Adiankraic series air new symbolic genera for equation to phase moments in Feynman path integrals. Guided in this light, we proceed by constructing Lagrangians actions for the N = 3 supermultiplet YI /(iDI X) for I = 1, 2, 3, where YI and X are standard, Salam-Strathdee superfields: YI fermionic and X bosonic. The system, bilinear in the component fields exhibits a total of thirteen free parameters, seven of which specify Zeeman-like coupling to external background (magnetic) fluxes. All but special subsets of this parameter space describe aperiodic oscillatory responses, some of which are found to be surprisingly controlled by the golden ratio, [phi] = 1.61803, Ref [52]. It is further determined that these Lagrangians allow an N = 3 - > 4 supersymmetric extension to the Chiral-Chiral and Chiral-twistedChiral multiplet, while a subset admits two inequivalent such extensions. In a natural proiii gression, a continuum of observably and usefully inequivalent, finite-dimensional off-shell representations of worldline N = 4 extended supersymmetry are explored, that are variate from one another but in the value of a tuning parameter, Ref [53]. Their dynamics turns out to be nontrivial already when restricting to just bilinear Lagrangians. In particular, we find a 34-parameter family of bilinear Lagrangians that couple two differently tuned supermultiplets to each other and to external magnetic fluxes, where the explicit parameter dependence is unremovable by any field redefinition and is therefore observable. This offers the evaluation of X-phase sensitive, off-shell path integrals with promising correlations to group product decompositions and to deriving source emergences of higher-order background flux-forms on 2-dimensional manifolds, the stacks of which comprise space-time volumes. Application to nonlinear sigma models would naturally follow, having potential use in M- and F- string theories.

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