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Dissertations / Theses on the topic 'Group algebras; Symmetry'
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1
Hills, Robert K. "The algebra of a class of permutation invariant irreducible operators." Thesis, University of Oxford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260729.
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Moreira, Rodriguez Rivera Walter. "Products of representations of the symmetric group and non-commutative versions." Texas A&M University, 2008. http://hdl.handle.net/1969.1/85938.
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We construct a new operation among representations of the symmetric group that
interpolates between the classical internal and external products, which are defined in
terms of tensor product and induction of representations. Following Malvenuto and
Reutenauer, we pass from symmetric functions to non-commutative symmetric functions
and from there to the algebra of permutations in order to relate the internal and
external products to the composition and convolution of linear endomorphisms of the
tensor algebra. The new product we construct corresponds to the Heisenberg product
of endomorphisms of the tensor algebra. For symmetric functions, the Heisenberg
product is given by a construction which combines induction and restriction of representations.
For non-commutative symmetric functions, the structure constants of
the Heisenberg product are given by an explicit combinatorial rule which extends a
well-known result of Garsia, Remmel, Reutenauer, and Solomon for the descent algebra.
We describe the dual operation among quasi-symmetric functions in terms of
alphabets.
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Hill, David Edward. "The Jantzen-Shapovalov form and Cartan invariants of symmetric groups and Hecke algebras /." view abstract or download file of text, 2007. http://proquest.umi.com/pqdweb?did=1400959351&sid=1&Fmt=2&clientId=11238&RQT=309&VName=PQD.
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Thesis (Ph. D.)--University of Oregon, 2007.<br>Typescript. Includes vita and abstract. Includes bibliographical references (leaves 107-108). Also available for download via the World Wide Web; free to University of Oregon users.
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Han, Gang. "Clifford algebras associated with symmetric pairs /." View abstract or full-text, 2004. http://library.ust.hk/cgi/db/thesis.pl?MATH%202004%20HAN.
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Tan, Kai Meng. "Small defect blocks of symmetric group algebras." Thesis, University of Cambridge, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.624153.
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Ruff, Oliver. "Completely splittable representations of symmetric groups and affine Hecke algebras /." view abstract or download file of text, 2005. http://wwwlib.umi.com/cr/uoregon/fullcit?p3190545.
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Thesis (Ph. D.)--University of Oregon, 2005.<br>Typescript. Includes vita and abstract. Includes bibliographical references (leaves 44-45). Also available for download via the World Wide Web; free to University of Oregon users.
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Fayers, Matthew. "Representations of symmetric groups and Schur algebras." Thesis, University of Cambridge, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.620642.
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Abubakar, Ahmed Bello. "The structure of symmetric group algebras at arbitrary characteristic." Thesis, University of East London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300326.
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Zwicknagl, Sebastian. "Equivariant Poisson algebras and their deformations /." view abstract or download file of text, 2006. http://proquest.umi.com/pqdweb?did=1280144671&sid=2&Fmt=2&clientId=11238&RQT=309&VName=PQD.
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Thesis (Ph. D.)--University of Oregon, 2006.<br>Typescript. Includes vita and abstract. "In this dissertation I investigate Poisson structures on symmetric and exterior algebras of modules over complex reductive Lie algebras. I use the results to study the braided symmetric and exterior algebras"--P. 1. Includes bibliographical references (leaves 150-152). Also available for download via the World Wide Web; free to University of Oregon users.
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Manriquez, Adam. "Symmetric Presentations, Representations, and Related Topics." CSUSB ScholarWorks, 2018. https://scholarworks.lib.csusb.edu/etd/711.
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The purpose of this thesis is to develop original symmetric presentations of finite non-abelian simple groups, particularly the sporadic simple groups. We have found original symmetric presentations for the Janko group J1, the Mathieu group M12, the Symplectic groups S(3,4) and S(4,5), a Lie type group Suz(8), and the automorphism group of the Unitary group U(3,5) as homomorphic images of the progenitors 2*60 : (2 x A5), 2*60 : A5, 2*56 : (23 : 7), and 2*28 : (PGL(2,7):2), respectively. We have also discovered the groups 24 : A5, 34 : S5, PSL(2,31), PSL(2,11), PSL(2,19), PSL(2,41), A8, 34 : S5, A52, 2• A52, 2 : A62, PSL(2,49), 28 : A5, PGL(2,19), PSL(2,71), 24 : A5, 24 : A6, PSL(2,7), 3 x PSL(3,4), 2• PSL(3,4), PSL(3,4), 2• (M12 : 2), 37:S7, 35 : S5, S6, 25 : S6, 35 : S6, 25 : S5, 24 : S6, and M12 as homomorphic images of the permutation progenitors 2*60 : (2 x A5), 2*60 : A5, 2*21 : (7: 3), 2*60 : (2 x A5), 2*120 : S5, and 2*144 : (32 : 24). We have given original proof of the 2*n Symmetric Presentation Theorem. In addition, we have also provided original proof for the Extension of the Factoring Lemma (involutory and non-involutory progenitors). We have constructed S5, PSL(2,7), and U(3,5):2 using the technique of double coset enumeration and by way of linear fractional mappings. Furthermore, we have given proofs of isomorphism types for 7 x 22, U(3,5):2, 2•(M12 : 2), and (4 x 2) :• 22.
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Paget, Rowena. "Representation theory of symmetric groups and related algebras." Thesis, University of Oxford, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270235.
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Krawzik, Naomi. "Graded Hecke Algebras for the Symmetric Group in Positive Characteristic." Thesis, University of North Texas, 2020. https://digital.library.unt.edu/ark:/67531/metadc1707315/.
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Graded Hecke algebras are deformations of skew group algebras which arise from a group acting on a polynomial ring. Over fields of characteristic zero, these deformations have been studied in depth and include both symplectic reflection algebras and rational Cherednik algebras as examples. In Lusztig's graded affine Hecke algebras, the action of the group is deformed, but not the commutativity of the vectors. In Drinfeld's Hecke algebras, the commutativity of the vectors is deformed, but not the action of the group. Lusztig's algebras are all isomorphic to Drinfeld's algebras in the nonmodular setting. We find new deformations in the modular setting, i.e., when the characteristic of the underlying field divides the order of the group. We use Poincare-Birkhoff-Witt conditions to classify these deformations arising from the symmetric group acting on a polynomial ring in arbitrary characteristic, including the modular case.
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Ault, Shaun V. "On the Symmetric Homology of Algebras." The Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1218237992.
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Bogdanic, Dusko. "Graded blocks of group algebras." Thesis, University of Oxford, 2010. http://ora.ox.ac.uk/objects/uuid:faeaaeab-1fe6-46a9-8cbb-f3f633131a73.
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In this thesis we study gradings on blocks of group algebras. The motivation to study gradings on blocks of group algebras and their transfer via derived and stable equivalences originates from some of the most important open conjectures in representation theory, such as Broue’s abelian defect group conjecture. This conjecture predicts the existence of derived equivalences between categories of modules. Some attempts to prove Broue’s conjecture by lifting stable equivalences to derived equivalences highlight the importance of understanding the connection between transferring gradings via stable equivalences and transferring gradings via derived equivalences. The main idea that we use is the following. We start with an algebra which can be easily graded, and transfer this grading via derived or stable equivalence to another algebra which is not easily graded. We investigate the properties of the resulting grading. In the first chapter we list the background results that will be used in this thesis. In the second chapter we study gradings on Brauer tree algebras, a class of algebras that contains blocks of group algebras with cyclic defect groups. We show that there is a unique grading up to graded Morita equivalence and rescaling on an arbitrary basic Brauer tree algebra. The third chapter is devoted to the study of gradings on tame blocks of group algebras. We study extensively the class of blocks with dihedral defect groups. We investigate the existence, positivity and tightness of gradings, and we classify all gradings on these blocks up to graded Morita equivalence. The last chapter deals with the problem of transferring gradings via stable equivalences between blocks of group algebras. We demonstrate on three examples how such a transfer via stable equivalences is achieved between Brauer correspondents, where the group in question is a TI group.
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Yu, Jun. "Symmetric subgroups of automorphism groups of compact simple Lie algebras /." View abstract or full-text, 2009. http://library.ust.hk/cgi/db/thesis.pl?MATH%202009%20YU.
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Wickramasekara, Sujeewa, and sujeewa@physics utexas edu. "Symmetry Representations in the Rigged Hilbert Space Formulation of." ESI preprints, 2001. ftp://ftp.esi.ac.at/pub/Preprints/esi993.ps.
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Penrod, Keith. "Infinite product groups /." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd1977.pdf.
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Franjou, Vincent. "Modules et algebres instables sur l'algebre de steenrod : une etude aux nilpotents pres." Nantes, 1988. http://www.theses.fr/1988NANT2003.
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L'algebre de cohomologie modulo 2 d'un espace est un module instable sur l'algebre de steenrod a. Le premier chapitre etudie la categorie abelienne obtenue comme quotient de la categorie des a-modules instables par sa sous-categorie des a-modules nilpotents. On definit d'abord une notion de poids qui induit une filtration naturelle sur tout a-module instable. Cela nous permet de classifier les objets simples par les representations modulaires simples des groupes symetriques. La cohomologie des classifiants des 2-groupes abeliens elementaires est etudiee en exemple. On obtient aussi que notre categorie est localement finie, et on classifie ses objets injectifs. Le second chapitre se propose de representer les a-algebres instables par des diagrammes, similaires a ceux que quillen introduit pour la cohomologie des groupes compacts. Plus precisement, on associe a toute a-algebre instable une categorie qui permet de la reconstruire "aux nilpotents pres". On en obtient une simplification illustree par des exemples
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Kessar, Radha. "Blocks and source algebras for the double covers of the symmetric groups /." The Ohio State University, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=osu148786754173406.
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Whitehouse, Sarah Ann. "Gamma (co)homology of commutative algebras and some related representations of the symmetric group." Thesis, University of Warwick, 1994. http://wrap.warwick.ac.uk/4214/.
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This thesis covers two related subjects: homology of commutative algebras and certain representations of the symmetric group. There are several different formulations of commutative algebra homology, all of which are known to agree when one works over a field of characteristic zero. During 1991-1992 my supervisor, Dr. Alan Robinson, motivated by homotopy-theoretic ideas, developed a new theory, Γ-homology [Rob, 2]. This is a homology theory for commutative rings, and more generally rings commutative up to homotopy. We consider the algebraic version of the theory. Chapter I covers background material and Chapter II describes Γ-homology. We arrive at a spectral sequence for Γ-homology, involving objects called tree spaces. Chapter III is devoted to consideration of the case where we work over a field of characteristic zero. In this case the spectral sequence collapses. The tree space, Tn, which is used to describe Γ-homology has a natural action of the symmetric group Sn. We identify the representation of Sn on its only non-trivial homology group as that given by the first Eulerian idempotent en(l) in QSn. Using this, we prove that Γ-homology coincides with the existing theories over a field of characteristic zero. In fact, the tree space, Tn, gives a representation of Sn+l. In Chapter IV we calculate the character of this representation. Moreover, we show that each Eulerian representation of Sn is the restriction of a representation of Sn+1. These Eulerian representations are given by idempotents en(j), for j=1, ..., n, in QSn, and occur in the work of Barr [B], Gerstenhaber and Schack [G-S, 1], Loday [L, 1,2,3] and Hanlon [H]. They have been used to give decompositions of the Hochschild and cyclic homology of commutative algebras in characteristic zero. We describe our representations of Sn+1 as virtual representations, and give some partial results on their decompositions into irreducible components. In Chapter V we return to commutative algebra homology, now considered in prime characteristic. We give a corrected version of Gerstenhaber and Schack's [G-S, 2] decomposition of Hochschild homology in this setting, and give the analagous decomposition of cyclic homology. Finally, we give a counterexample to a conjecture of Barr, which states that a certain modification of Harrison cohomology should coincide with André/Quillen cohomology.
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Winarski, Rebecca R. "Symmetry, isotopy, and irregular covers." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/51868.
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We say that a covering space of the surface S over X has the Birman--Hilden property if the subgroup of the mapping class group of X consisting of mapping classes that have representatives that lift to S embeds in the mapping class group of S modulo the group of deck transformations. We identify one necessary condition and one sufficient condition for when a covering space has this property. We give new explicit examples of irregular branched covering spaces that do not satisfy the necessary condition as well as explicit covering spaces that satisfy the sufficient condition. Our criteria are conditions on simple closed curves, and our proofs use the combinatorial topology of curves on surfaces.
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Nash, David A. 1982. "Graded representation theory of Hecke algebras." Thesis, University of Oregon, 2010. http://hdl.handle.net/1794/10871.
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xii, 76 p. : ill. A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number.<br>We study the graded representation theory of the Iwahori-Hecke algebra, denoted by Hd , of the symmetric group over a field of characteristic zero at a root of unity. More specifically, we use graded Specht modules to calculate the graded decomposition numbers for Hd . The algorithm arrived at is the Lascoux-Leclerc-Thibon algorithm in disguise. Thus we interpret the algorithm in terms of graded representation theory.
We then use the algorithm to compute several examples and to obtain a closed form for the graded decomposition numbers in the case of two-column partitions. In this case, we also precisely describe the 'reduction modulo p' process, which relates the graded irreducible representations of Hd over [Special characters omitted.] at a p th -root of unity to those of the group algebra of the symmetric group over a field of characteristic p.<br>Committee in charge: Alexander Kleshchev, Chairperson, Mathematics;
Jonathan Brundan, Member, Mathematics;
Boris Botvinnik, Member, Mathematics;
Victor Ostrik, Member, Mathematics;
William Harbaugh, Outside Member, Economics
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Penrod, Keith G. "Infinite Product Group." BYU ScholarsArchive, 2007. https://scholarsarchive.byu.edu/etd/976.
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The theory of infinite multiplication has been studied in the case of the Hawaiian earring group, and has been seen to simplify the description of that group. In this paper we try to extend the theory of infinite multiplication to other groups and give a few examples of how this can be done. In particular, we discuss the theory as applied to symmetric groups and braid groups. We also give an equivalent definition to K. Eda's infinitary product as the fundamental group of a modified wedge product.
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Black, Samson 1979. "Representations of Hecke algebras and the Alexander polynomial." Thesis, University of Oregon, 2010. http://hdl.handle.net/1794/10847.
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viii, 50 p. : ill. A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number.<br>We study a certain quotient of the Iwahori-Hecke algebra of the symmetric group Sd , called the super Temperley-Lieb algebra STLd. The Alexander polynomial of a braid can be computed via a certain specialization of the Markov trace which descends to STLd. Combining this point of view with Ocneanu's formula for the Markov trace and Young's seminormal form, we deduce a new state-sum formula for the Alexander polynomial. We also give a direct combinatorial proof of this result.<br>Committee in charge: Arkady Vaintrob, Co-Chairperson, Mathematics
Jonathan Brundan, Co-Chairperson, Mathematics;
Victor Ostrik, Member, Mathematics;
Dev Sinha, Member, Mathematics;
Paul van Donkelaar, Outside Member, Human Physiology
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Grindstaff, Dustin J. "Symmetric Presentations and Generation." CSUSB ScholarWorks, 2015. https://scholarworks.lib.csusb.edu/etd/202.
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The aim of this thesis is to generate original symmetric presentations for finite non-abelian simple groups. We will discuss many permutation progenitors, including but not limited to 2*14 : D28, 2∗9 : 3•(32), 3∗9 : 3•(32), 2∗21 : (7X3) : 2 as well as monomial progenitors, including 7∗5 :m A5, 3∗5 :m S5. We have included their homomorphic images which include the Mathieu group M12, 2•J2, 2XS(4, 5), as well as, many PGL′s, PSL′s and alternating groups. We will give proofs of the isomorphism types of each progenitor, either by hand using double coset enumeration or computer based using MAGMA. We have also constructed Cayley graphs of the following groups, 25 : S5 over 2∗5 : S5, PSL(2, 8) over 2∗7 : D14, M12 over a maximal subgroup, 2XS5. We have developed a lemma using relations to factor permutation progenitors of the form m∗n : N to give an isomorphism of mn : N . Motivated by Robert T. Curtis’ research, we will present a program using MAGMA that, when given a target finite non-abelian simple group, the program will generate possible control groups to write progenitors that will give the given finite non-abelian simple group. Iwasawa’s lemma is also discussed and used to prove PSL(2, 8) and M12 to be simple groups.
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Lamp, Leonard B. "SYMMETRIC PRESENTATIONS OF NON-ABELIAN SIMPLE GROUPS." CSUSB ScholarWorks, 2015. https://scholarworks.lib.csusb.edu/etd/222.
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The goal of this thesis is to show constructions of some of the sporadic groups such as the Mathieu group, M12, J1, Projective Special Linear groups, PSL(2,8), and PSL(2,11), Unitary group U(3,3) and many other non-abelian simple groups. Our purpose is to find all simple non-abelian groups as homomorphic images of permutation or monomial progenitors, as well grasping a deep understanding of group theory and extension theory to determine groups up to isomorphisms. The progenitor, developed by Robert T. Curtis, is a semi-direct product of the following form: P≅2*n: N = {πw | π ∈ N, w a reduced word in the ti} where 2*n denotes a free product of n copies of the cyclic group of order 2 generated by involutions ti for 1 ≤ i≤ n; and N is a transitive permutation group of degree n which acts on the free product by permuting the involuntary generators by conjugation. Thus we develop methods for factoring by a suitable any number of relations in the hope of finding all non-abelian simple groups, and in particular one of the 26 Sporadic simple groups. Then the algorithm for double coset enumeration together with the first isomorphic theorem aids us in proving the homomorphic image of the group we have constructed. After being presented with a group G, we then compute the composition series to solve extension problems. Given a composition such as G = G0 ≥ G1 ≥ ….. ≥ Gn-1 ≥ Gn = 1 and the corresponding factor groups G0/G1 = Q1,…,Gn-2/Gn-1 = Qn-1,Gn-1/Gn = Qn. We note that G1 = 1, implying Gn-1 = Qn. As we move through the next composition factor we see that Gn-2/Qn = Qn-1, so that Gn-2 is an extension of Qn-1 by Qn. Following this procedure we can recapture G from the products of Qi and thus solve the extension problem. The Jordan-Holder theorem then allows us to develop a process to analyze all finite groups if we knew all finite simple groups and could solve their extension problem, hence arriving at the isomorphism type of the group. We will present how we solve extensions problems while our main focus will lie on extensions that will include the following: semi-direct products, direct products, central extensions and mixed extensions.Lastly, we will discuss Iwasawa's Lemma and how double coset enumeration aids us in showing the simplicity of some of our groups.
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Jones, Philip Robert. "Homology from posets." Thesis, University of East Anglia, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302072.
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Wasserman, Benjamin. "Variétés magnifiques de rang deux." Grenoble 1, 1997. http://www.theses.fr/1997GRE10037.
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Soit g un groupe reductif complexe (connexe). Les g-varietes magnifiques les plus connues sont celles de rang zero, a savoir les varietes de drapeaux generalisees g/p, celles de rang un, classifiees par akhiezer, et certaines varietes symetriques completes decrites par de concini et procesi comme par exemple le celebre espace des coniques completes. Il y a recemment un interet renouvele pour les varietes magnifiques de rang deux car des travaux de luna, brion, pauer et knop montrent que celles-ci jouent un role clef dans la theorie des varietes spheriques. L'objectif de ce travail est la classification des varietes magnifiques de rang deux. Ces dernieres peuvent se caracteriser de la maniere suivante. Ce sont des g-varietes lisses completes contenant quatre orbites, a savoir une orbite dense et deux orbites de codimension un dont les adherences d#1 et d#2 se coupent transversalement en la quatrieme orbite qui est de codimension deux. Nous avons recueilli nos resultats dans des tables, contenant groupes d'isotropie et donnees combinatoires en rapport avec la theorie des varietes spheriques.
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Pedone, M. (Matteo). "Algebraic methods for constructing blur-invariant operators and their applications." Doctoral thesis, Oulun yliopisto, 2015. http://urn.fi/urn:isbn:9789526208770.
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Abstract Image acquisition devices are always subject to physical limitations that often manifest as distortions in the appearance of the captured image. The most common types of distortions can be divided into two categories: geometric and radiometric distortions. Examples of the latter ones are: changes in brightness, contrast, or illumination, sensor noise and blur. Since image blur can have many different causes, it is usually not convenient and also computationally expensive to develop ad hoc algorithms to correct each specific type of blur. Instead, it is often possible to extract a blur-invariant representation of the image, and utilize such information to make algorithms that are insensitive to blur. The work presented here mainly focuses on developing techniques for the extraction and the application of blur-invariant operators. This thesis contains several contributions. First, we propose a generalized framework based on group theory to constructively generate complete blur-invariants. We construct novel operators that are invariant to a large family of blurs occurring in real scenarios: namely, those blurs that can be modeled by a convolution with a point-spread function having rotational symmetry, or combined rotational and axial symmetry. A second important contribution is represented by the utilization of such operators to develop an algorithm for blur-invariant translational image registration. This algorithm is experimentally demonstrated to be more robust than other state-of-the-art registration techniques. The blur-invariant registration algorithm is then used as pre-processing steps to several restoration methods based on image fusion, like depth-of-field extension, and multi-channel blind deconvolution. All the described techniques are then re-interpreted as a particular instance of Wiener deconvolution filtering. Thus, the third main contribution is the generalization of the blur-invariants and the registration techniques to color images, by using respectively a representation of color images based on quaternions, and the quaternion Wiener filter. This leads to the development of a blur-and-noise-robust registration algorithm for color images. We observe experimentally a significant increase in performance in both color texture recognition, and in blurred color image registration<br>Tiivistelmä Kuvauslaitteet ovat aina fyysisten olosuhteiden rajoittamia, mikä usein ilmenee tallennetun kuvan ilmiasun vääristyminä. Yleisimmät vääristymätyypit voidaan jakaa kahteen kategoriaan: geometrisiin ja radiometrisiin distortioihin. Jälkimmäisestä esimerkkejä ovat kirkkauden, kontrastin ja valon laadun muutokset sekä sensorin kohina ja kuvan sumeus. Koska kuvan sumeus voi johtua monista tekijöistä, yleensä ei ole tarkoitukseen sopivaa eikä laskennallisesti kannattavaa kehittää ad hoc algoritmeja erityyppisten sumeuksien korjaamiseen. Sitä vastoin on mahdollista erottaa kuvasta sumeuden invariantin edustuma ja käyttää tätä tietoa sumeudelle epäherkkien algoritmien tuottamiseen. Tässä väitöskirjassa keskitytään esittämään, millaisia eri tekniikoita voidaan käyttää sumeuden invarianttien operaattoreiden muodostamiseen ja sovellusten kehittämiseen. Tämä opinnäyte sisältää useammanlaista tieteellistä vaikuttavuutta. Ensiksi, väitöskirjassa esitellään ryhmäteoriaan perustuva yleinen viitekehys, jolla voidaan generoida sumeuden invariantteja. Konstruoimme uudentyyppisiä operaattoreita, jotka ovat monenlaiselle kuvaustilanteessa ilmenevälle sumeudelle invariantteja. Kyseessä ovat ne rotationaalisesti (ja/tai aksiaalisesti) symmetrisen sumeuden lajit, jotka voidaan mallintaa pistelähteen hajaantumisen funktion (PSF) konvoluutiolla. Toinen tämän väitöskirjan tärkeä tutkimuksellinen anti on esitettyjen sumeuden invarianttien operaattoreiden hyödyntäminen algoritmin kehittelyssä, joka on käytössä translatorisen kuvan rekisteröinnissä. Tällainen algoritmi on tässä tutkimuksessa osoitettu kokeellisesti johtavia kuvien rekisteröintitekniikoita robustimmaksi. Sumeuden invariantin rekisteröinnin algoritmia on käytetty esiprosessointina tässä tutkimuksessa useissa kuvien restaurointimenetelmissä, jotka perustuvat kuvan fuusioon, kuten syväterävyysaluelaajennus ja monikanavainen dekonvoluutio. Kaikki kuvatut tekniikat ovat lopulta uudelleen tulkittu erityistapauksena Wienerin dekonvoluution suodattimesta. Näin ollen tutkimuksen kolmas saavutus on sumeuden invarianttien ja rekisteröintiteknikoiden yleistäminen värikuviin käyttämällä värikuvien kvaternion edustumaa sekä Wienerin kvaternion suodatinta. Havaitsemme kokeellisesti merkittävän parannuksen sekä väritekstuurin tunnistuksessa että sumean kuvan rekisteröinnissä
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at, Andreas Cap@esi ac. "Equivariant Symplectic Geometry of Cotangent Bundles." Moscow Math. J. 1, No.2 (2001) 287-299, 2001. ftp://ftp.esi.ac.at/pub/Preprints/esi996.ps.
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Chassaniol, Arthur. "Contributions à l'étude des groupes quantiques de permutations." Thesis, Clermont-Ferrand 2, 2016. http://www.theses.fr/2016CLF22709/document.
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Dans cette thèse nous étudions le groupe quantique d’automorphismes des graphes finis, introduit par Banica et Bichon. Dans un premier temps nous montrerons un théorème de structure du groupe quantique d’automorphismes du produit lexicographique de deux graphes finis réguliers, qui généralise un résultat classique de Sabidussi. Ce théorème donne une condition nécessaire et suffisante pour que ce groupe quantique s’exprime comme le produit en couronne libre des groupes quantiques d’automorphismes de ces deux graphes. Dans un deuxième temps, nous expliciterons certaines améliorations de résultats de Banica, Bichon et Chenevier permettant d’obtenir des critères de non symétrie quantique sur les graphes, à l’aide des outils développés par les auteurs susmentionnés.Enfin, pour poursuivre ces recherches, nous développerons une autre méthode utilisant la dualité de Tannaka-Krein et inspirée de l’étude des groupes quantiques compacts orthogonaux par Banica et Speicher. Celle-ci nous permettra, à l’aide d’une étude orbitale approfondie des graphes sommets-transitifs, d’énoncer une condition suffisante pour qu’un graphe ait des symétries quantiques ; condition qui a vocation à être aussi nécessaire mais ceci reste une conjecture à ce stade<br>In this thesis we study the quantum automorphism group of finite graphs, introduces by Banica and Bichon. First we will prove a theorem about the structure of the quantum automorphism group of the lexicographic product of two finite regular graphs. It is a quantum generalization of a classical result of Sabidussi. This theorem gives a necessary and sufficient condition for this quantum group to be discribe as the free wreath product of the quantum automorphism groups of these two graphs. Then, we will give some improvement of Banica, Bichon and Chenevier results, to obtain a quantum non-symmetry criteria on graphs, using tools developped by the above authors. Finally, to continue this research, we will describe another method using Tannaka-Krein duality and inspired by the study of orthogonal compact groups by Banica and Speicher. This will enable us, with a thorough orbital study of vertex-transitive graphs, to state a sufficient condition for a graph to have quantum symmetries ; condition which is intended to be also necessary but this remains conjecture at this point
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Fonseca, Marlon Pimenta. "Representações dos grupos simétrico e alternante e aplicações às identidades polinomiais." Universidade Federal de São Carlos, 2014. https://repositorio.ufscar.br/handle/ufscar/5912.
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Previous issue date: 2014-11-28<br>Financiadora de Estudos e Projetos<br>In this dissertation we ll present a discussion about the Representations of the Symmetric Group Sn and Alternating Group An. We ll study basics results of the Young s Theory about the representations of the Symmetric Group and discover the decomposition of the algebra FSn in simple subalgebras. After, we ll utilize this decomposition to find the decomposition of the algebra FAn in simple subalgebras. Finally, we ll use this decompositions, together with the PI Theory, for get the sequence of A-codimensions for the Grassmann Algebra (Exterior Algebra) infinitely generated.<br>Neste trabalho apresentamos uma discussão a respeito das Representações dos Grupos Simétrico Sn e do Grupo Alternante An. Estudaremos resultados básicos da Teoria de Young sobre as representações do grupo simétrico para encontrarmos a decomposição da álgebra de grupo FSn em subálgebras simples. Depois utilizaremos tal decomposição para encontrar a decomposição da álgebra de grupo FAn em subálgebras simples. Por fim empregaremos as informações a respeito das decomposições acima citadas, juntamente com a PI-Teoria, para obter a sequência de A-codimensões para a álgebra de Grassmann (álgebra exterior) infinitamente gerada.
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Gilliers, Nicolas. "Non-commutative gauge symmetry and pseudo-unitary diffusions." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS113.
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Cette thèse est consacrée à l’étude de deux questions très différentes, reliées par les outils que nous utilisons pour les étudier. La première question est celle de la définition des théories de jauge sur un réseau avec un groupe de structure non commutatif. Ici, non commutatif ne signifie pas non Abelian, mais plutôt non commutatif au sens général de la géométrie non commutative. La deuxième question est celle du comportement des diffusions Browniennes sur des groupes matriciels non compacts d’un type spécifique, à savoir des groupes de matrices pseudo-orthogonales, pseudo-unitaires ou pseudo-symplectiques. Dans le premier chapitre, nous étudions des théories de jauge quantiques sur un réseau et leur limite continue sur le plan euclidien ayant une algèbre de Zhang pour groupe de stuc-ture. Les algèbres de Zhang sont des analogues non commutatifs des groupes et contiennent la classe des groupes duaux de Voiculescu. Nous nous intéressons donc aux analogues non commutatifs des champs de jauges quantiques, que nous décrivons par l’holonomie aléatoire qu’ils induisent. Nous proposons une définition générale d’un champ d’holonomies ayant une symétrie de jauge présentant la structure d’une algèbre de Zhang, et construisons un tel champ à partir d’un processus quantique de Lévy sur une algèbre de Zhang. Dans le deuxième chapitre, nous étudions les approximations matricielles des champs maîtres en dimensions supérieures construits dans le chapitre précédent. Ces approximations (en distribution non commutative) sont obtenues en extrayant des blocs d’une diffusion unitaire Brownienne (à coefficients dans les algèbres de nombres réels, complexes ou quaternioniques) et en laissant la dimension de ces blocs tendre vers l’infini. Nous divisons notre étude en deux parties : dans la première, nous extrayons des blocs carrés tandis que dans la seconde, nous autorisons des blocs rectangulaires. Dans les deux derniers chapitres, nous utilisons les outils introduits (algèbres de Zhang et diagrammes de Brauer colorés) dans les deux premiers pour étudier des diffusions sur des groupes de matrices pseudo-unitaires. Nous prouvons la convergence non commutative des mouvements Browniens pseudo-unitaires que nous considérons vers des semi-groupes libres avec amalgamation sous l’hypothèse de convergence de la signature normalisée de la métrique de l’espace sous-jacent. Dans le cas déployé, c’est-à-dire, qu’au moins asymptotiquement, la métrique a autant de directions négatives que de directions positives, la distribution limite est la distribution d’un processus de Lévy, solution d’une équation différentielle stochastique libre. Nous laissons ouverte la question d’une telle réalisation de la distribution limite dans le cas général. De plus, nous présentons des résultats numériques sur la convergence de la distribution spectrale de ces matrices aléatoires et faisons deux conjectures. Dans le dernier chapitre, nous prouvons la normalité asymptotique des fluctuations<br>This thesis is devoted to the study of two quite different questions, which are related by the tools that we use to study them. The first question is that of the definition of lattice gauge theories with a non-commutative structure group. Here, by non-commutative, we do not mean non-Abelian, but instead non-commutative in the general sense of non-commutative geometry. The second question is that of the behaviour of Brownian diffusions on non-compact matrix groups of a specific kind, namely groups of pseudo-orthogonal, pseudo-unitary or pseudo-symplectic matrices. In the first chapter, we investigate lattice and continuous quantum gauge theories on the Euclidean plane with a structure group that is replaced by a Zhang algebra. Zhang algebras are non-commutative analogues of groups and contain the class of Voiculescu’s dual groups. We are interested in non-commutative analogues of random gauge fields, which we describe through the random holonomy that they induce. We propose a general definition of a holonomy field with Zhang gauge symmetry, and construct such a field starting from a quantum Lévy process on a Zhang algebra. As an application, we define higher dimensional generalizations of the so-called master field. In the second chapter, we study matricial approximations of higher dimensional master fields constructed in the previous chapter. These approximations (in non-commutative distribution) are obtained by extracting blocks of a Brownian unitary diffusion (with entries in the algebras of real, complex or quaternionic numbers) and letting the dimension of these blocks tend to infinity. We divide our study into two parts: in the first one, we extract square blocks while in the second one we allow rectangular blocks. In both cases, free probability theory appears as the natural framework in which the limiting distributions are most accurately described. In the last two chapters, we use tools introduced (Zhang algebras and coloured Brauer diagrams) in the first two ones to study Brownian motion on pseudo-unitary matrices in high dimensions. We prove convergence in non-commutative distribution of the pseudo-unitary Brownian motions we consider to free with amalgamation semi-groups under the hypothesis of convergence of the normalized signature of the metric. In the split case, meaning that at least asymptotically the metric has as much negative directions as positive ones, the limiting distribution is that of a free Lévy process, which is a solution of a free stochastic differential equation. We leave open the question of such a realization of the limiting distribution in the general case. In addition we provide (intriguing) numerical evidences for the convergence of the spectral distribution of such random matrices and make two conjectures. At the end of the thesis, we prove asymptotic normality for the fluctuations
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Junior, Fernando Martins Antoneli. "Subalgebras maximais das álgebras de Lie semisimples, quebra de simetria e o código genético." Universidade de São Paulo, 1998. http://www.teses.usp.br/teses/disponiveis/45/45132/tde-01092009-171526/.
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O propósito deste trabalho é dar uma contribuição ao projeto iniciado por Hornos & Hornos que visa explicar as degenerescências do código genético como resultado de sucessivas quebras de simetria ocorridas durante sua evolução. O modelo matemático usado requer a construção de todas as representações irredutíveis de dimensão 64 das álgebras de Lie simples (chamadas representações de códons) e a análise de suas regras de ramicação sob redução a subalgebras. A classicação de todas as possibilidades é baseada na classicação das subalgebras maximais das álgebras de Lie semisimples obtida por Dynkin. No presente trabalho, os resultados de Dynkin são apresentados em linguagem e notação moderna e são aplicados ao problema de construir todas as possíveis cadeias de subalgebras maximais das álgebras de Lie simples B_6 = so(13) e D_7 = so(14) e de identicar aquelas que reproduzem as degenerescências do código genético.<br>The purpose of this work is to make a contribution to the project initiated by Hornos & Hornos which aims at explaining the degeneracy of the genetic code as the result of a sequence of symmetry breaking that occurred during its evolution. The mathematical model employed requires the construction of all 64-dimensional irreducible representations of simple Lie algebras (called codon representations) and the analysis of their branching rules under reduction to sub-algebras. The classification of all possibilities is based on Dynkins classification of the maximal sub-algebras of semi-simple Lie algebras. In the present work, Dynkins results are presented in modern language and notation and are applied to the problem of constructing all possible chains of maximal sub-algebras of the simple Lie algebras B_6 = so(13) and D_7 = so(14) and of identifying all those that reproduce the degeneracies of the genetic code.
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Juršėnas, Rytis. "Algebraic development of many-body perturbation theory in theoretical atomic spectroscopy." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2010. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2010~D_20101223_153004-84982.
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The principal goals of the thesis are subjected to general methods and forms of effective operators by the nowadays demands of theoretical application of many-body perturbation theory to atomic physics. The present theoretical research follows up step by step by systematic observation of various possibilities to restrict the Fock space operators to their irreducible subspaces and the classification of irreducible tensor operators which represent the physical as well as the effective interactions. To ground the results of the thesis, the symbolic preparation of obtained expressions is strictly proved mathematically. Most of the main results are listed in theorems. The doctoral dissertation contains 101 pages, 5 sections, 4 appendices, 40 tables and 9 figures. The main results described in the present dissertation have been published in journals of physical and mathematical sciences.<br>Šis darbas yra skirtas šiuolaikinės atomo trikdžių teorijos matematinio aparato, paremto efektinių operatorių formalizmu, plėtojimui. Darbe nuosekliai ir sistemingai, pradedant nuo pačių bendriausių principų, nagrinėjami Foko erdvės apribojimo į redukavimo grupių neredukuotinus poerdvius metodai bei pateikiama neredukuotinų tenzorinių operatorių, charakterizuojančių fizikines ir efektines sąveikas, klasifikacija bendrais ir tam tikrais atskirais atvejais. Gautos išraiškos ir iš jų išplaukiančios išvados yra grindžiamos matematine kalba. Dauguma esminių rezultatų yra suformuluoti teoremų pavidalu. Disertaciją sudaro 101 puslapis, 5 skyriai, 4 priedai, 40 lentelių ir 9 paveikslėliai. Pagrindiniai rezultatai, pateikti disertacijoje, yra publikuoti fizikos ir matematikos mokslų žurnaluose.
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Santos, Laercio Jose dos. "Semigrupos gerados por classes laterais e funções caracteristicas de semigrupos." [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/305821.
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Orientador: Luiz Antonio Barrera San Martin<br>Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Matemática, Estatística e Computação Científica<br>Made available in DSpace on 2018-08-10T09:55:18Z (GMT). No. of bitstreams: 1
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Previous issue date: 2007<br>Resumo: Este trabalho divide-se em duas partes. Na primeira parte, obtemos condições necessárias e suficientes para que uma família de classes laterais de um subgrupo de Lie gere um subsemigrupo com interior não vazio. Aplicamos essas condições aos pares simétricos, onde o grupo é semi-simples. Como consequência, mostramos que o subgrupo dos pontos fixos de vários automorfismos involutivos é maximal como semigrupo. Na segunda parte, definimos a função característica de um subsemigrupo de um grupo de Lie semi-simples e, encontramos um subconjunto do domínio de definição dessa função. Fizemos isto usando a teoria geral de semigrupos em grupos semi-simples. Usamos a função característica de um semigrupo, com algumas hipóteses adicionais, para introduzir uma métrica Riemanniana nas órbitas do subgrupo das unidades do semigrupo. Com essa métrica, obtemos uma condição necessária para que um subgrupo possa ser imerso em um semigrupo próprio com interior não vazio<br>Abstract: This work is made of two parts. In the first one, we gave necessary and sufficient conditions for a family of cosets of a Lie subgroup to generate a subsemigroup with nonempty interior. We apply these conditions to symmetric pairs where the group is semi-simple. As a consequence we prove that for several involutive automorphisms the fixed points subgroup is a maximal
semigroup. In the second part, we define a characteristic function of a subsemigroup of a semi- simple Lie group and we find a subset where the function is defined. This is made through general theory of semigroups in semi-simple groups. The characteristic function
is used, together with some additional hypothesis, for to create a Riemannian metric in the orbits of the unity subgroup of the semigroup. With this metric we gave a necessary condition for a subgroup be embedded in a proper semigroup with nonempty interior<br>Doutorado<br>Teoria de Lie<br>Doutor em Matemática
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Pons, Viviane. "Combinatoire algébrique liée aux ordres sur les permutations." Phd thesis, Université Paris-Est, 2013. http://tel.archives-ouvertes.fr/tel-00952773.
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Cette thèse se situe dans le domaine de la combinatoire algébrique et porte sur l'étude et les applications de trois ordres sur les permutations : les deux ordres faibles (gauche et droit) et l'ordre fort ou de Bruhat. Dans un premier temps, nous étudions l'action du groupe symétrique sur les polynômes multivariés. En particulier, les opérateurs de emph{différences divisées} permettent de définir des bases de l'anneau des polynômes qui généralisent les fonctions de Schur aussi bien du point de vue de leur construction que de leur interprétation géométrique. Nous étudions plus particulièrement la base des polynômes de Grothendieck introduite par Lascoux et Schützenberger. Lascoux a montré qu'un certain produit de polynômes peut s'interpréter comme un produit d'opérateurs de différences divisées. En développant ce produit, nous ré-obtenons un résultat de Lenart et Postnikov et prouvons de plus que le produit s'interprète comme une somme sur un intervalle de l'ordre de Bruhat. Nous présentons aussi l'implantation que nous avons réalisée sur Sage des polynômes multivariés. Cette implantation permet de travailler formellement dans différentes bases et d'effecteur des changements de bases. Elle utilise l'action des différences divisées sur les vecteurs d'exposants des polynômes multivariés. Les bases implantées contiennent en particulier les polynômes de Schubert, les polynômes de Grothendieck et les polynômes clés (ou caractères de Demazure).Dans un second temps, nous étudions le emph{treillis de Tamari} sur les arbres binaires. Celui-ci s'obtient comme un quotient de l'ordre faible sur les permutations : à chaque arbre est associé un intervalle de l'ordre faible formé par ses extensions linéaires. Nous montrons qu'un objet plus général, les intervalles-posets, permet de représenter l'ensemble des intervalles du treillis de Tamari. Grâce à ces objets, nous obtenons une formule récursive donnant pour chaque arbre binaire le nombre d'arbres plus petits ou égaux dans le treillis de Tamari. Nous donnons aussi une nouvelle preuve que la fonction génératrice des intervalles de Tamari vérifie une certaine équation fonctionnelle décrite par Chapoton. Enfin, nous généralisons ces résultats aux treillis de $m$-Tamari. Cette famille de treillis introduite par Bergeron et Préville-Ratelle était décrite uniquement sur les chemins. Nous en donnons une interprétation sur une famille d'arbres binaires en bijection avec les arbres $m+1$-aires. Nous utilisons cette description pour généraliser les résultats obtenus dans le cas du treillis de Tamari classique. Ainsi, nous obtenons une formule comptant le nombre d'éléments plus petits ou égaux qu'un élément donné ainsi qu'une nouvelle preuve de l'équation fonctionnelle des intervalles de $m$-Tamari. Pour finir, nous décrivons des structures algébriques $m$ qui généralisent les algèbres de Hopf $FQSym$ et $PBT$ sur les permutations et les arbres binaires
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Thibault, de Chanvalon Manon. "Groupes quantiques : actions sur des modules hilbertiens et calculs différentiels." Thesis, Clermont-Ferrand 2, 2014. http://www.theses.fr/2014CLF22521/document.
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Gerber, Thomas. "Matrices de décomposition des algèbres d'Ariki-Koike et isomorphismes de cristaux dans les espaces de Fock." Phd thesis, Université François Rabelais - Tours, 2014. http://tel.archives-ouvertes.fr/tel-01057480.
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Cette thèse est consacrée à l'étude des représentations modulaires des algèbres d'Ariki-Koike, et des liens avec la théorie des cristaux et des bases canoniques de Kashiwara via le théorème de catégorification d'Ariki. Dans un premier temps, on étudie, grâce à des outils combinatoires, les matrices de décomposition de ces algèbres en généralisant les travaux de Geck et Jacon. On classifie entièrement les cas d'existence et de non-existence d'ensembles basiques, en construisant explicitement ces ensembles lorsqu'ils existent. On explicite ensuite les isomorphismes de cristaux pour les représentations de Fock de l'algèbre affine quantique de type A affine. On construit alors un isomorphisme particulier, dit canonique, qui permet entre autres une caractérisation non-récursive de n'importe quelle composante connexe du cristal. On souligne également les liens avec la combinatoire des mots sous-jacente à la structure cristalline des espaces de Fock, en décrivant notamment un analogue de la correspondance de Robinson-Schensted-Knuth pour le type A affine.
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Delcroix-Oger, Bérénice. "Hyperarbres et Partitions semi-pointées : aspects combinatoires, algébriques et homologiques." Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10243/document.
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Cette thèse est consacrée à l’étude combinatoire, algébrique et homologique des hyperarbres et des partitions semi-pointées. Nous étudions plus précisément des structures algébriques et homologiques construites à partir des hyperarbres, puis des partitions semi-pointées.Après un bref rappel des notions utilisées, nous utilisons la théorie des espèces de structure afin de déterminer l’action du groupe symétrique sur l’homologie du poset des hyperarbres. Cette action s’identifie à l’action du groupe symétrique liée à la structure anti-cyclique de l’opérade PreLie. Nous raffinons ensuite nos calculs sur une graduation de l’homologie, appelée homologie de Whitney. Cette étude motive l'introduction de la notion d’hyperarbre aux arêtes décorées par une espèce. Une bijection des hyperarbres décorés avec des arbres en boîtes et des partitions décorées permet d’obtenir une formule close pour leur cardinal, à l’aide d’un codage de Prüfer. Nous adaptons ensuite les méthodes de calcul de caractères sur les algèbres de Hopf d’incidence, introduites par W. Schmitt dans le cas de familles de posets bornés, à des familles de posets non bornés vérifiant certaines propriétés. Nous appliquons ensuite cette adaptation aux posets des hyperarbres. Enfin, au cours de notre étude une généralisation des posets des partitions et des posets des partitions pointées apparaît : les poset des partitions semi-pointées. Nous montrons que ces posets sont aussi Cohen-Macaulay, avant de déterminer à l’aide de la théorie des espèces une formule close pour la dimension de l’unique groupe d’homologie non trivial de ces posets<br>This thesis is dedicated to the combinatorial, algebraic and homological study of hypertrees and semi-pointed partitions. More precisely, we study algebraic and homological structures built from hypertrees and semi-pointed partitions. After recalling briefly the notions needed, we use the theory of species of structures to compute the action of the symmetric group on the homology of the hypertree posets. This action is the same as the action of the symmetric group linked with the anticyclic structure of the PreLie operad. We refine our computations on a grading of the homology : Whitney homology. This study is a motivation for the introduction of the notion of edge-decorated hypertrees. A one-to-one correspondence of decorated hypertrees with box trees and decorated partitions enables us to compute a close formula for the cardinality of decorated hypertrees, thanks to a Prüfer code. Moreover, we adapt computation methods of characters on incidence Hopf algebras, introduced by W. Schmitt for families of bounded posets, to families of unbounded posets satisfying some additional properties, called triangle and diamond posets. We apply these results to the hypertree posets. Finally, we unveil a new family of posets : the semi-pointed partition posets, which generalize both partition posets and pointed partition posets. We show the Cohen-Macaulayness of these posets and obtain, thanks to species theory, a closed formula for the dimension of its unique homology group, which extend the ones established for partition posets and pointed partition posets
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Gomez, John Hermes Castillo. "Propriedades de Lie de elementos simétricos sob involuções orientadas em álgebras de grupo." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/45/45131/tde-04012013-170011/.
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Sejam $F$ um corpo de característica diferente de $2$ e $G$ um grupo. A partir da involução clássica, que envia cada elemento em seu inverso, e uma orientação do grupo $G$ é possível definir uma involução clássica orientada na álgebra de grupo $FG$. O objetivo desta tese é estudar propriedades de Lie do conjunto dos elementos simétricos $(FG)^+$ e, em alguns casos, do conjunto dos elementos anti-simétricos $(FG)^-$. Primeiro, abordamos o caso quando $G$ não tem elementos de ordem $2$. Aqui, mostramos que se $(FG)^+$ (ou $(FG)^-$) é Lie nilpotente ou Lie $n$-Engel, então $FG$ também é Lie nilpotente ou Lie $m$-Engel, respectivamente. Depois, consideramos o caso quando $G$ contém uma cópia do grupo quatérnio de ordem $8$. Neste caso, caracterizamos completamente as álgebras de grupo tais que $(FG)^+$ é fortemente Lie nilpotente, Lie nilpotente e Lie $n$-Engel. Como consequência, provamos que o conjunto das unidades simétricas deste tipo de grupos é nilpotente. Estudamos também o caso em que quando $G$ não contém uma cópia do grupo quatérnio de ordem $8$. Em particular, apresentamos um exemplo que mostra que os resultados obtidos em pesquisas anteriores, com a involução clássica, não devem ser esperados ao trabalhar com involuções clássicas orientadas. Não entanto, damos alguns casos especiais de grupos nos quais esses resultados são obtidos. Finalmente, estudamos o índice de Lie nilpotência de $(FG)^+$. Estabelecemos uma condição necessária e suficiente, para que o índice de Lie nilpotência de $(FG)^+$ e a classe de nilpotência das unidades simétricas de uma álgebra de grupo Lie nilpotente sejam o maior possível. Além disso, consideramos a situação em que o grupo $G$ contém uma cópia de $Q_8$.<br>Let $F$ be a field of characteristic different from $2$ and $G$ a group. From the classical involution, which sends each element in its inverse and an orientation of $G$, it is possible to define an oriented classical involution on the group algebra $FG$. The goal of this thesis is to study Lie properties of the set of symmetric elements $(FG)^+$ and, in some cases, of the set of skew-symmetric elements $(FG)^-$. We first deal with the case when $G$ does not have elements of order $2$. In this situation, we show that if $(FG)^+$ (or $(FG)^-$) is Lie nilpotent or Lie $n$-Engel, then the whole group algebra $FG$ satisfies the same property. Later we consider the case when $G$ contains a copy of the quaternion group of order $8$. In this instance, we give a complete description of the group algebras such that $(FG)^+$ is strongly Lie nilpotent, Lie nilpotent and Lie $n$-Engel. As a consequence, we get that the set of symmetric units of this kind of groups is nilpotent. Furthermore, we study the case when $G$ does not contain a copy of the quaternion group of order $8$. Here, we present an example that shows that the previews results obtained in former works, with the classical involution, may not hold with an oriented classical involution. However, we give some kinds of groups for which those results are achieved. Finally, we study the Lie nilpotency index of $(FG)^+$. It is given a necessary and sufficient condition to the Lie nilpotency index of $(FG)^+$ and the nilpotency class of the symmetric units to be maximal, in a Lie nilpotent group algebra. In addition, we consider the situation when $G$ contains a copy of the quaternion group of order $8$.
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McDermott, Matthew. "Fast Algorithms for Analyzing Partially Ranked Data." Scholarship @ Claremont, 2014. http://scholarship.claremont.edu/hmc_theses/58.
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Imagine your local creamery administers a survey asking their patrons to choose their five favorite ice cream flavors. Any data collected by this survey would be an example of partially ranked data, as the set of all possible flavors is only ranked into subsets of the chosen flavors and the non-chosen flavors. If the creamery asks you to help analyze this data, what approaches could you take? One approach is to use the natural symmetries of the underlying data space to decompose any data set into smaller parts that can be more easily understood. In this work, I describe how to use permutation representations of the symmetric group to create and study efficient algorithms that yield such decompositions.
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Wills, Luis Alberto. "Finite group graded lie algebraic extensions and trefoil symmetric relativity, standard model, yang mills and gravity theories." Thesis, 2008. http://hdl.handle.net/10125/11725.
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Mode of access: World Wide Web.<br>Thesis (Ph. D.)--University of Hawaii at Manoa, 2004.<br>Includes bibliographical references (leaves 159-164).<br>Electronic reproduction.<br>Also available by subscription via World Wide Web<br>x, 164 leaves, bound ill. 29 cm
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Shakalli, Tang Jeanette. "Deformations of Quantum Symmetric Algebras Extended by Groups." Thesis, 2012. http://hdl.handle.net/1969.1/ETD-TAMU-2012-05-10855.
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The study of deformations of an algebra has been a topic of interest for quite some time, since it allows us to not only produce new algebras but also better understand the original algebra. Given an algebra, finding all its deformations is, if at all possible, quite a challenging problem. For this reason, several specializations of this question have been proposed. For instance, some authors concentrate their efforts in the study of deformations of an algebra arising from an action of a Hopf algebra.
The purpose of this dissertation is to discuss a general construction of a deformation of a smash product algebra coming from an action of a particular Hopf algebra. This Hopf algebra is generated by skew-primitive and group-like elements, and depends on a complex parameter. The smash product algebra is defined on the quantum symmetric algebra of a nite-dimensional vector space and a group. In particular, an application of this result has enabled us to find a deformation of such a smash product algebra which is, to the best of our knowledge, the first known example of a deformation in which the new relations in the deformed algebra involve elements of the original vector space. Finally, using Hochschild cohomology, we show that these
deformations are nontrivial.
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Zimba, Kenneth. "Fischer-Clifford matrices of the generalized symmetric group and some associated groups." Thesis, 2005. http://hdl.handle.net/10413/1688.
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With the classification of finite simple groups having been completed in 1981, recent work in group theory has involved the study of the structures of simple groups. The character tables of maximal subgroups of simple groups give substantive information about these groups. Most of the maximal subgroups of simple groups are of extension type. Some of the maximal subgroups of simple groups contain constituents of the generalized symmetric groups. Here we shall be interested in discussing such groups which we may call groups associated with the generalized symmetric groups. There are several well developed methods for calculating the character tables of group extensions. However Fischer [17] has given an effective method for calculating the character tables of some group extensions including the generalized symmetric group B (m, n). Actually work on the characters of wreath products with permutation groups dates back to Specht's work [61], through the works of Osima [49] and Kerber [33]. And more recently other people have worked on characters of wreath products with symmetric groups, these amongst others include Darafshesh and Iranmanesh [14], List and Mahmoud [36], Puttaswamiah [52], Read [55, 56], Saeed-Ul-Islam [59] and Stembridge [64]. It is well known that the character table of the generalized symmetric group B(m, n), where m and n are positive integers, can be constructed in GAP [22] with B(m, n) considered as the wreath product of the cyclic group Zm of order m with the symmetric group Sn' For example Pfeiffer [50] has given programmes which compute the character tables of wreath products with symmetric groups in GAP. However it may be necessary to obtain the partial character table of a group in hand rather than its complete character table. Further due to limited workspace in GAP, the wreath product method can only be used to compute character tables of B(m, n) for small values of m and n. It is for these reasons amongst others that Fischer's method is sometimes used to construct the character tables of such groups. groups B(2, 6) and B(3, 5) of orders 46080 and 29160 is done here. We have also used Programme 5.2.4 to construct the Fischer-Clifford matrices of the groups B(2, 12) and B(4, 5) of orders 222 x 35 X 52 X 7 x 11 and 213 x 3 x 5 respectively. Due to lack of space here we have given the Fischer-Clifford matrices of B(2, 12) and B(4,5) on the compact disk submitted with this thesis. However note that these matrices are the equivalent form of the Fischer-Clifford matrices of B(2, 12) and B(4,5). In [35] R.J. List has presented a method for constructing the Fischer-Clifford matrices of group extensions of an irreducible constituent of the elementary abelian group 2n by a symmetric group. The other aim of our work is to adapt the combinatorial method in [5] to the construction of the Fischer-Clifford matrices of some group extensions associated with B(m, n), using a similar method as the one used in [35]. Examples are given on the application of this adaptation to some groups associated with the groups B(2, 6), B(3,3) and B(3, 5). In this thesis we have constructed the character tables of the groups B(2, 6) and B(3,5) and some group extensions associated with these two groups and B(3, 3). We have also constructed the character tables of the groups B(2, 12) and B(4, 5) in our work, these character tables are given on the compact disk submitted with this thesis. The correctness of all the character tables constructed in this thesis has been tested in GAP. The main working programmes (Programme 2.2.3, Programme 3.1.9, Programme 3.1.10, Programme 5.2.1, Programme 5.2.4 and Programme 5.2.2) are given on the compact disk submitted with this thesis. It is anticipated that with further improvements, a number of the programmes given here will be incorporated into GAP. Indeed with further research work the programmes given here should lead to an alternative programme for computing the character table of B(m, n).<br>Thesis (Ph.D.)- University of KwaZulu-Natal, Pietermaritzburg, 2005.
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Tysse, Jill Elizabeth. "The centers of spin symmetric and spin hyperoctahedral group algebras /." 2008. http://wwwlib.umi.com/dissertations/fullcit/3322506.
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Verma, Abhinav. "Irreducible Representations Of The Symmetric Group And The General Linear Group." Thesis, 2011. http://etd.iisc.ernet.in/handle/2005/1909.
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Representation theory is the study of abstract algebraic structures by representing their elements as linear transformations or matrices. It provides a bridge between the abstract symbolic mathematics and its explicit applications in nearly every branch of mathematics. Combinatorial representation theory aims to use combinatorial objects to model representations, thus answering questions in this field combinatorially. Combinatorial objects are used to help describe, count and generate representations. This has led to a rich symbiotic relationship where combinatorics has helped answer algebraic questions and algebraic techniques have helped answer combinatorial questions.
In this thesis we discuss the representation theory of the symmetric group and the general linear group. The theory of these two families of groups is often considered the corner stone of combinatorial representation theory. Results and techniques arising from the study of these groups have been successfully generalized to a very wide class of groups. An overview of some of the generalizations can be found in [BR99]. There are also many avenues for further generalizations which are currently being explored.
The constructions of the Specht and Schur modules that we discuss here use the concept of Young tableaux. Young tableaux are combinatorial objects that were introduced by the Reverend Alfred Young, a mathematician at Cambridge University, in 1901. In 1903, Georg Frobenius applied them to the study of the symmetric group. Since then, they have been found to play an important role in the study of symmetric functions, representation theory of the symmetric and complex general linear groups and Schubert calculus of Grassmannians. Applications of Young tableaux to other branches of mathematics are still being discovered.
When drawing and labelling Young tableaux there are a few conflicting conventions in the literature, throughout this thesis we shall be following the English notation. In chapter 1 we shall make a few definitions and state some results which will be used in this thesis.
In chapter 2 we discuss the representations of the symmetric group. In this chapter we define the Specht modules and prove that they describe all the irreducible representations of Sn. We conclude with a discussion about the ring of Sn representations which is used to prove some identities of Specht modules.
In chapter 3 we discuss the representations of the general linear group. In this chapter we define the Schur modules and prove that they describe all the irreducible rational representations of GLmC. We also show that the set of tableaux forms an indexing set for a basis of the Schur modules.
In chapter 4 we describe a relation between the Specht and Schur modules. This is a corollary to the more general Schur-Weyl duality, an overview of which can be found in [BR99].
The appendix contains the code and screen-shots of two computer programs that were written as part of this thesis. The programs have been written in C++ and the data structures have been implemented using the Standard Template Library. The first program gives us information about the representations of Sn for a given n. For a user defined n it will list all the Specht modules corresponding to that n, their dimensions and the standard tableaux corresponding to their basis elements. The second program gives information about a certain representation of GLmC. For a user defined m and λ it gives the dimension and the semistandard tableaux corresponding to the basis elements of the Schur module Eλ .
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Bashe, Mantombi Beryl. "Equivalence and symmetry groups of a nonlinear equation in plasma physics." Thesis, 2016. http://hdl.handle.net/10539/20598.
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Degree awarded with distinction on 6 December 1995.
A research report submitted to the Faculty of Science, University of the
Witwatersrand, in fulfilment of the requirements for the degree of Masters.
Johannesburg, 1995.<br>In this work we give a brief overview of the existing group classification methods
of partial differential equations by means of examples. On top of these methods
we introduce another new method which classify according to low-dimensional Lie
elgebras, One can ask: What is the aim of introducing a new method whilst there
are existing methods? This question is answered in the following paragraph.
Firstly we classify our system of non-linear partial differential equations using the
preliminary group classification method (one of the existing methods). The results
are not different from what; Euler, Steeb and Mulsor have obtained in 1991 and 1992.
That is, this method does not yield new information.
This new method which classifies according to low-dimensional Lie algebras is used
to classify a general system of equations from plasma physics. Finally, using this
method we completely classify our system for four-dimensionnl algebras. For a partial
differential equation to be completely classified using this method, it must admit a
low-dimensional Lie algebra.
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Lemmer, Ryan Lee. "The paradigms of mechanics : a symmetry based approach." Thesis, 1996. http://hdl.handle.net/10413/4899.
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An overview of the historical developments of the paradigms of classical mechanics, the free particle, oscillator and the Kepler problem, is given ito (in terms of) their conserved quantities. Next, the orbits of the three paradigms are found from quadratic forms. The quadratic forms are constructed using first integrals found by the application of Poisson's theorem. The orbits are presented ito expanding surfaces defined by the quadratic forms. The Lie and Noether symmetries of the paradigms are investigated. The free particle is discussed in detail and an overview of the work done on the oscillator and Kepler problem is given. The Lie and Noether theories are compared from various aspects. A technical description of Lie groups and algebras is given. This provides a basis for a discussion of the historical development of the paradigms of mechanics ito their group properties. Lastly the paradigms are discussed ito of Quantum Mechanics.<br>Thesis (M.Sc.)-University of Natal, 1996.
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Pantazi, Hara. "First integrals for the Bianchi universes : supplementation of the Noetherian integrals with first integrals obtained by using Lie symmetries." 1997. http://hdl.handle.net/10413/5103.
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