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Dissertations / Theses on the topic 'LIE ALGEBRAS, REPRESENTATION THEORY'
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1
Carr, Andrew Nickolas. "Lie Algebras and Representation Theory." OpenSIUC, 2016. https://opensiuc.lib.siu.edu/theses/1988.
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Lemay, Joel. "Valued Graphs and the Representation Theory of Lie Algebras." Thèse, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/20168.
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Quivers (directed graphs) and species (a generalization of quivers) as well as their representations play a key role in many areas of mathematics including combinatorics, geometry, and algebra. Their importance is especially apparent in their applications to the representation theory of associative algebras, Lie algebras, and quantum groups. In this thesis, we discuss the most important results in the representation theory of species, such as Dlab and Ringel’s extension of Gabriel’s theorem, which classifies all species of finite and tame representation type. We also explain the link between species and K-species (where K is a field). Namely, we show that the category of K-species can be viewed as a subcategory of the category of species. Furthermore, we prove two results about the structure of the tensor ring of a species containing no oriented cycles that do not appear in the literature. Specifically, we prove that two such species have isomorphic tensor rings if and only if they are isomorphic as “crushed” species, and we show that if K is a perfect field, then the tensor algebra of a K-species tensored with the algebraic closure of K is isomorphic to, or Morita equivalent to, the path algebra of a quiver.
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Cao, Mengyuan. "Representation Theory of Lie Colour Algebras and Its Connection with the Brauer Algebras." Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/38125.
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In this thesis, we study the representation theory of Lie colour algebras. Our strategy follows the work of G. Benkart, C. L. Shader and A. Ram in 1998, which is to use the Brauer algebras which appear as the commutant of the orthosymplectic Lie colour algebra when they act on a k-fold tensor product of the standard representation. We give a general combinatorial construction of highest weight vectors using tableaux, and compute characters of the irreducible summands in some borderline cases. Along the way, we prove the RSK-correspondence for tableaux and the PBW theorem for Lie colour algebras.
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Muth, Robert. "Representations of Khovanov-Lauda-Rouquier algebras of affine Lie type." Thesis, University of Oregon, 2016. http://hdl.handle.net/1794/20432.
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We study representations of Khovanov-Lauda-Rouquier (KLR) algebras of affine Lie type. Associated to every convex preorder on the set of positive roots is a system of cuspidal modules for the KLR algebra. For a balanced order, we study imaginary semicuspidal modules by means of `imaginary Schur-Weyl duality'. We then generalize this theory from balanced to arbitrary convex preorders for affine ADE types. Under the assumption that the characteristic of the ground field is greater than some explicit bound, we prove that KLR algebras are properly stratified. We introduce affine zigzag algebras and prove that these are Morita equivalent to arbitrary imaginary strata if the characteristic of the ground field is greater than the bound mentioned above. Finally, working in finite or affine affine type A, we show that skew Specht modules may be defined over the KLR algebra, and real cuspidal modules associated to a balanced convex preorder are skew Specht modules for certain explicit hook shapes.
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Lampetti, Enrico. "Nilpotent orbits in semisimple Lie algebras." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/23595/.
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This thesis is dedicated to the introductory study of the so-called nilpotent orbits in a semisimple complex Lie algebra g, i.e., the orbits of nilpotent elements under the adjoint action of the adjoint group Gad with Lie algebra g. These orbits have an extremely rich structure and lie at the interface of Lie theory, algebraic geometry, symplectic geometry, and geometric representation theory.
The Jacobson and Morozov Theorem relates the orbit of a nilpotent element X in a semisimple complex Lie algebra g with a triple {H,X,Y} that generates a subalgebra of g isomorphic to sl(2,C). There is a parabolic subalgebra associated to this triple that permits to attach a weight to each node of the Dynkin diagram of g. The resulting diagram is called a weighted Dynkin diagram associated with the nilpotent orbit of X. This is a complete invariant of the orbit that one can use in order to
show that there are only _nitely many nilpotent orbits in g.
The thesis is organized as follows: the first three chapters contain some preliminary material on Lie algebras (Chapter 1), on Lie groups (Chapter 3) and on the representation theory of sl(2,C) (Chapter 2). Chapter 4 and 5 are the heart of the thesis. Namely,
Jacobson-Morozov, Kostant and Mal'cev Theorems are proved in Chapter 4 and Chapter 5 is dedicated to the construction of weighted Dynkin diagrams. As an example the
conjugacy classes of nilpotent elements in sl(n,C) are described in detail and a formula for their dimension is given. In this case, as well as in the case of all classical Lie algebras, the description of the orbits can be done in terms of partitions and
tableaux.
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Rakotoarisoa, Andriamananjara Tantely. "The Bala-Carter Classification of Nilpotent Orbits of Semisimple Lie Algebras." Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/36058.
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Conjugacy classes of nilpotent elements in complex semisimple Lie algebras are classified using the Bala-Carter theory. In this theory, nilpotent orbits in g are parametrized by the conjugacy classes of pairs (l,pl) of Levi subalgebras of g and distinguished parabolic subalgebras of [l,l]. In this thesis we present this theory and use it to give a list of representatives for nilpotent orbits in so(8) and from there we give a partition-type parametrization of them.
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O'Dell, Connor. "Non-Resonant Uniserial Representations of Vec(R)." Thesis, University of North Texas, 2018. https://digital.library.unt.edu/ark:/67531/metadc1157650/.
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The non-resonant bounded uniserial representations of Vec(R) form a certain class of extensions composed of tensor density modules, all of whose subquotients are indecomposable. The problem of classifying the extensions with a given composition series is reduced via cohomological methods to computing the solution of a certain system of polynomial equations in several variables derived from the cup equations for the extension. Using this method, we classify all non-resonant bounded uniserial extensions of Vec(R) up to length 6. Beyond this length, all such extensions appear to arise as subquotients of extensions of arbitrary length, many of which are explained by the psuedodifferential operator modules. Others are explained by a wedge construction and by the pseudodifferential operator cocycle discovered by Khesin and Kravchenko.
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Meinel, Joanna [Verfasser]. "Affine nilTemperley-Lieb algebras and generalized Weyl algebras: Combinatorics and representation theory / Joanna Meinel." Bonn : Universitäts- und Landesbibliothek Bonn, 2016. http://d-nb.info/1122193874/34.
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Lemay, Joel. "Geometric Realizations of the Basic Representation of the Affine General Linear Lie Algebra." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32866.
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The realizations of the basic representation of the affine general linear Lie algebra on (r x r) matrices are well-known to be parametrized by partitions of r and have an explicit description in terms of vertex operators on the bosonic/fermionic Fock space. In this thesis, we give a geometric interpretation of these realizations in terms of geometric operators acting on the equivariant cohomology of certain Nakajima quiver varieties.
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Leonardi, Davide. "Kac-Moody algebras and representations of quivers." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/20796/.
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La tesi introduce il lettore alla teoria delle rappresentazioni di algebre di Lie e quivers. Viene studiata la teoria delle algebre di Lie semisemplici e delle algebre di Kac-Moody su un campo algebricamente chiuso di caratteristica zero. Si introduce la teoria delle rappresentazioni di quiver e si dimostra un criterio per decidere qualora una data rappresentazione di un dato quiver sia assolutamente indecomponibile o meno.
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Gontcharov, Aleksandr. "On the Conjugacy of Maximal Toral Subalgebras of Certain Infinite-Dimensional Lie Algebras." Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/26086.
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We will extend the conjugacy problem of maximal toral subalgebras for Lie algebras of the form $\g{g} \otimes_k R$ by considering $R=k[t,t^{-1}]$ and $R=k[t,t^{-1},(t-1)^{-1}]$, where $k$ is an algebraically closed field of characteristic zero and $\g{g}$ is a direct limit Lie algebra. In the process, we study properties of infinite matrices with entries in a B\'zout domain and we also look at how our conjugacy results extend to universal central extensions of the suitable direct limit Lie algebras.
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Leclerc, Marc-Antoine. "Homogeneous Projective Varieties of Rank 2 Groups." Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/23558.
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Root systems are a fundamental concept in the theory of Lie algebra. In this thesis, we will use two different kind of graphs to represent the group generated by reflections acting on the elements of the root system. The root
systems we are interested in are those of type A2, B2 and G2. After drawing the graphs, we will study the algebraic groups corresponding to those root systems. We will use three different techniques to give a geometric description of the homogeneous spaces G/P where G is the algebraic group corresponding to the root system and P is one of its parabolic subgroup. Finally, we will make a link between the graphs and the multiplication of
basis elements in the Chow group CH(G/P).
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Afentoulidis-Almpanis, Spyridon. "Noncubic Dirac Operators for finite-dimensional modules." Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0035.
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Cette thèse porte sur l’étude des opérateurs de Dirac non-cubiques dans le cadre de la théorie des représentations des groupes de Lie. Après avoir présenté des notions de la théorie de Lie et des algèbres de Clifford, nous rappelons les propriétés principales des opérateurs de Dirac cubiques D introduits par Kostant en 1999. Ces résultats ont rapidement suscité un vif intérêt. En particulier, à la fin des années 2000, Vogan introduit une cohomologie définie par l’opérateur de Kostant et suggère une classification cohomologique des représentations. La cohomologie de Dirac a été calculée pour diverses familles de représentations, telles que les séries discrètes, les modules Aq(>) ou les modules de dimension finie. Pour les modules de dimension finie, la cohomologie de Dirac coïncide avec le noyau de D. Il apparait que l’opérateur de Dirac de Kostant est une version algébrique d’un opérateur différentiel issu d’une famille continue d’opérateurs de Dirac géométriques introduits par Slebarski dans les années 1980 dans le cadre de fibrés au- dessus d’espaces homogènes G/H de groupes compacts. Ce qui distingue l’opérateur de Dirac de Kostant est qu’il est le seul membre de cette famille dont le carré, généralisant une formule de Parthasarathy, diffère de l’opérateur de Casimir à un scalaire près. Cette propriété a des applications importantes en théorie des représentations des groupes de Lie. Le carré des opérateurs de Dirac non-cubiques, i.e des autres membres de la famille d’opérateurs de Slebarski, a été calculé par Agricola qui a également établit des liens précis entre ces opérateurs non-cubiques et la théorie des cordes en physique. Par ailleurs, les opérateurs de Dirac non-cubiques sont des opérateurs différentiels invariants, et donc leur noyau est le siège de représentations (de dimension finie) de groupes compacts. Dans cette thèse nous étudions le noyau des opérateurs de Dirac non-cubiques, et nous montrons, sous certaines conditions sur les espaces homogènes G/H, que ce noyau contient le noyau de l’opérateur de Dirac cubique. Nous obtenons en fait une formule explicite pour le noyau que nous appliquons aux cas des algèbres de Lie classiques et des algèbres de Lie exceptionnelles. Nous constatons que certaines propriétés des opérateurs non-cubiques sont analogues à celles de l’opérateur de Dirac de Kostant, tel que l’indice. Nous déduisons également quelques observations sur les opérateurs de Dirac géométrique non-cubiquesThis thesis focuses on the study of noncubic Dirac operators within the framework of representation theory of Lie groups. After recalling basic notions of Lie theory and Clifford algebras, we present the main properties of cubic Dirac operators D introduced by Kostant in 1999. These results quickly aroused great interest. In particular, in the late 1990’s, Vogan introduced a cohomology defined by Kostant operator D and suggested a cohomological classification of representations. Dirac cohomology was computed for various families of representations, such as the discrete series, Aq(>) modules or finite dimensional representations. It turns out that for finite dimensional modules, Dirac cohomology coincides with the kernel of D. It appears that Kostant’s Dirac operator is an algebraic version of a specific member of a continuous family of geometric Dirac operators introduced by Slebarski in the mid 1980’s in the context of bundles over homogeneous spaces G/H of compact groups. What distinguishes the cubic Dirac operator is that it is the only member of this family whose square, generalizing Parthasarathy’s formula, differs from the Casimir operator up to a scalar. This property has important applications in representation theory of Lie groups. The square of the noncubic Dirac operators, i.e. of the other members of Slebarski’s family, was calculated by Agricola who also established precise links between these noncubic operators and string theory in physics. Actually, noncubic Dirac operators are invariant differential operators, and therefore their kernels define (finite-dimensional) representations of compact groups. In this thesis we study the kernel of noncubic Dirac operators, and we show that, under certain conditions on the homogeneous spaces G/H, the kernel contains the kernel of the cubic Dirac operator. We obtain an explicit formula for the kernel which we apply to the case of classical Lie algebras and of exceptional Lie algebras. We remark that some properties of noncubic operators are analogous to those of Kostant cubic Dirac operator, such as the index. We also deduce some observations on noncubic geometric Dirac operators
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Webster, Benjamin. "On Representations of the Jacobi Group and Differential Equations." UNF Digital Commons, 2018. https://digitalcommons.unf.edu/etd/858.
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In PDEs with nontrivial Lie symmetry algebras, the Lie symmetry naturally yield Fourier and Laplace transforms of fundamental solutions. Applying this fact we discuss the semidirect product of the metaplectic group and the Heisenberg group, then induce a representation our group and use it to investigate the invariant solutions of a general differential equation of the form .
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Konan, Isaac. "Rogers-Ramanujan type identities : bijective proofs and Lie-theoretic approach." Thesis, Université de Paris (2019-....), 2020. http://www.theses.fr/2020UNIP7087.
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Cette thèse relève de la théorie des partitions d’entiers, à l’intersection de la combinatoire et de la théorie de nombres. En particulier, nous étudions les identités de type Rogers-Ramanujan sous le spectre de la méthode des mots pondérés. Une révision de cette méthode nous permet d’introduire de nouveaux objets combinatoires au delà de la notion classique de partitions d’entiers: partitions colorées généralisées. À l’aide de ces nouveaux éléments, nous établissons de nouvelles identités de type Rogers-Ramanujanvia deux approches différentes. La première approche consiste en une preuve combinatoire, essentiellement bijective, des identités étudiées. Cette approche nous a ainsi permis d’établir des identités généralisant plusieurs identités importantes de la théorie: l’identité de Schur et l’identité Göllnitz, l’identité de Glaisher généralisant l’identité d’Euler, les identités de Siladić, de Primc et de Capparelli issues de la théorie des représentations de algèbres de Lie affines. La deuxième approche fait appel à la théorie des cristaux parfaits, issue de la théorie des représentations des algèbres de Lie affines. Nous interprétons ainsi le caractère des représentations standards comme des identités de partitions d’entiers colorées généralisées. En particulier, cette approche permet d’établir des formules assez simplifiées du caractère pour toutes les représentations standards de niveau 1 des types affines A(1) n-1, A(2) 2n , D(2) n+1, A(2) 2n-1, B(1) n , D(1) nThe topic of this thesis belongs to the theory of integer partitions, at the intersection of combinatorics and number theory. In particular, we study Rogers-Ramanujan type identities in the framework of the method of weighted words. This method revisited allows us to introduce new combinatorial objects beyond the classical notion of integer partitions: the generalized colored partitions. Using these combinatorial objects, we establish new Rogers-Ramanujan identities via two different approaches.The first approach consists of a combinatorial proof, essentially bijective, of the studied identities. This approach allowed us to establish some identities generalizing many important identities of the theory of integer partitions : Schur’s identity and Göllnitz’ identity, Glaisher’s identity generalizing Euler’s identity, the identities of Siladić, of Primc and of Capparelli coming from the representation theory of affine Lie algebras. The second approach uses the theory of perfect crystals, coming from the representation theory of affine Lie algebras. We view the characters of standard representations as some identities on the generalized colored partitions. In particular, this approach allows us to establish simple formulas for the characters of all the level one standard representations of type A(1) n-1, A(2) 2n , D(2) n+1, A(2) 2n-1, B(1) n , D(1) n
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Stigner, Carl. "On tensor product of non-unitary representations of sl(2,R)." Thesis, Karlstad University, Division for Engineering Sciences, Physics and Mathematics, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-1047.
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The study of symmetries is an essential tool in modern physics. The analysis of symmetries is often carried out in the form of Lie algebras and their representations. Knowing the representation theory of a Lie algebra includes knowing how tensor products of representations behave. In this thesis two methods to study and decompose tensor products of representations of non-compact Lie algebras are presented and applied to sl(2,R). We focus on products containing non-unitary representations, especially the product of a unitary highest weight representation and a non-unitary finite dimensional. Such products are not necessarily decomposable. Following the theory of B. Kostant we use infinitesimal characters to show that this kind of tensor product is fully reducible iff the sum of the highest weights in the two modules is not a positive integer or zero. The same result is obtained by looking for an invariant coupling between the product module and the contragredient module of some possible submodule. This is done in the formulation by Barut & Fronsdal. From the latter method we also obtain a basis for the submodules consisting of vectors from the product module. The described methods could be used to study more complicated semisimple Lie algebras.
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Pike, Jeffrey. "Quivers and Three-Dimensional Lie Algebras." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32398.
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We study a family of three-dimensional Lie algebras that depend on a continuous parameter. We introduce certain quivers and prove that idempotented versions of the enveloping algebras of the Lie algebras are isomorphic to the path algebras of these quivers modulo certain ideals in the case that the free parameter is rational and non-rational, respectively. We then show how the representation theory of the introduced quivers can be related to the representation theory of quivers of affine type A, and use this relationship to study representations of the family of Lie algebras of interest. In particular, though it is known that this particular family of Lie algebras consists of algebras of wild representation type, we show that if we impose certain restrictions on weight decompositions, we obtain full subcategories of the category of representations that are of finite or tame representation type.
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Nilsson, Jonathan. "Simple Modules over Lie Algebras." Doctoral thesis, Uppsala universitet, Algebra och geometri, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-283061.
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Simple modules are the elemental components in representation theory for Lie algebras, and numerous mathematicians have worked on their construction and classification over the last century. This thesis consists of an introduction together with four research articles on the subject of simple Lie algebra modules. In the introduction we give a light treatment of the basic structure theory for simple finite dimensional complex Lie algebras and their representations. In particular we give a brief overview of the most well-known classes of Lie algebra modules: highest weight modules, cuspidal modules, Gelfand-Zetlin modules, Whittaker modules, and parabolically induced modules. The four papers contribute to the subject by construction and classification of new classes of Lie algebra modules. The first two papers focus on U(h)-free modules of rank 1 i.e. modules which are free of rank 1 when restricted to the enveloping algebra of the Cartan subalgebra. In Paper I we classify all such modules for the special linear Lie algebras sln+1(C), and we determine which of these modules are simple. For sl2 we also obtain some additional results on tensor product decomposition. Paper II uses the theory of coherent families to obtain a similar classification for U(h)-free modules over the symplectic Lie algebras sp2n(C). We also give a proof that U(h)-free modules do not exist for any other simple finite-dimensional algebras which completes the classification. In Paper III we construct a new large family of simple generalized Whittaker modules over the general linear Lie algebra gl2n(C). This family of modules is parametrized by non-singular nxn-matrices which makes it the second largest known family of gl2n-modules after the Gelfand-Zetlin modules. In Paper IV we obtain a new class of sln+2(C)-modules by applying the techniques of parabolic induction to the U(h)-free sln+1-modules we constructed in Paper I. We determine necessary and sufficient conditions for these parabolically induced modules to be simple.
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Mello, Ricardo Oliveira de. "A classificação dos sistemas elementares relativísticos em 1 + 1 dimensões." Universidade de São Paulo, 2002. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-13122013-112832/.
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nvestigando a estrutura dos sistemas elementares com simetria de Poincaré em 1 + 1 dimensões, devemos considerar o problema da eliminação das anomalias clássicas, que têm origem no segundo grupo de cohomologia não-trivial deste grupo dinâmico, gerando um termo de Wess-Zumino na ação da partícula relativística. Efetuamos a classificação geral de todos os sistemas elementares em 1 + 1 dimensões, em termos de co-órbitas, mostrando que existe um simplectomorfismo entre o espaço de fase reduzido da partícula e uma determinada co-órbita na álgebra de Lie dual à de Poincaré estendida.While researching the structure of elementar systems with Poincaré symmetry in 1+1 dimensions, we must be concerned about the problem of elimination of the classical anomalies, which arise from the non-trivial second cohomology group of this dynamical group, generating a Wess-Zumino term in the relativistic particle action. We classify all elementary systems in 1+1 dimensions in terms of co-orbits, showing that there is a symplectomorphism between the reduced phase space of the particle and a certain co-orbit in the Lie algebra dual to the extended Poincaré one.
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Jakovljevic, Cvjetan, and University of Lethbridge Faculty of Arts and Science. "Conformal field theory and lie algebras." Thesis, Lethbridge, Alta. : University of Lethbridge, Faculty of Arts and Science, 1996, 1996. http://hdl.handle.net/10133/37.
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Conformal field theories (CFTs) are intimately connected with Lie groups and their Lie algebras. Conformal symmetry is infinite-dimensional and therefore an infinite-dimensional algebra is required to describe it. This is the Virasoro algebra, which must be realized in any CFT. However, there are CFTs whose symmetries are even larger then Virasoro symmentry. We are particularly interested in a class of CFTs called Wess-Zumino-Witten (WZW) models. They have affine Lie algebras as their symmentry algebras. Each WZW model is based on a simple Lie group, whose simple Lie algebra is a subalgebra of its affine symmetry algebra. This allows us to discuss the dominant weight multiplicities of simple Lie algebras in light of WZW theory. They are expressed in terms of the modular matrices of WZW models, and related objects. Symmentries of the modular matrices give rise to new relations among multiplicities. At least for some Lie algebras, these new relations are strong enough to completely fix all multiplicities.iv, 80 leaves : ill. ; 28 cm.
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Burke, Heather Maria. "The Outer-Temperley-Lieb algebra structure and representation theory." Thesis, University of Leeds, 2013. http://etheses.whiterose.ac.uk/7831/.
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We define a new algebra the Outer-Temperley-Lieb algebra, OTLn(δ), as a fixed ring of the well known Temperley-Lieb algebra, with respect to an automorphism σ reflecting the known diagrammatic representations of the Temperley-Lieb elements in the vertical plane. We define the cell modules of the Outer-Temperley-Lieb algebra and determine that the algebra’s semi-simplicity is dependant entirely on that of the Temperley-Lieb algebra. We are therefore able to give the complete representation theory of the Outer-Temperley- Lieb algebra when it is semi-simple. The induction and restriction of the standard modules to higher and lower rank OTLn(δ) algebras is studied. We also begin a study of the representation theory of OTLn(δ) when it is not semi-simple by describing a large family of homomorphisms between standard modules and conclude with a conjecture on the labelling set of the blocks of the Outer-Temperley-Lieb algebra in the non semi-simple cases.
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Laking, Rosanna Davison. "String algebras in representation theory." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/string-algebras-in-representation-theory(c350436a-db9a-429d-a8a5-470dffc0974f).html.
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The work in this thesis is concerned with three subclasses of the string algebras: domestic string algebras, gentle algebras and derived-discrete algebras (of non-Dynkin type). The various questions we answer are linked by the theme of the Krull-Gabriel dimension of categories of functors. We calculate the Cantor-Bendixson rank of the Ziegler spectrum of the category of modules over a domestic string algebra. Since there is no superdecomposable module over a domestic string algebra, this is also the value of the Krull-Gabriel dimension of the category of finitely presented functors from the category of finitely presented modules to the category of abelian groups. We also give a description of a basis for the spaces of homomorphisms between pairs of indecomposable complexes in the bounded derived category of a gentle algebra. We then use this basis to describe the Hom-hammocks involving (possibly infinite) string objects in the homotopy category of complexes of projective modules over a derived-discrete algebra. Using this description, we prove that the Krull-Gabriel dimension of the category of coherent functors from a derived-discrete algebra (of non-Dynkin type) is equal to 2. Since the Krull-Gabriel dimension is finite, it is equal to the Cantor-Bendixson rank of the Ziegler spectrum of the homotopy category and we use this to identify the points of the Ziegler spectrum. In particular, we prove that the indecomposable pure-injective complexes in the homotopy category are exactly the string complexes. Finally, we prove that every indecomposable complex in the homotopy category is pure-injective, and hence is a string complex.
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Santacruz, Camilo Andres Angulo. "A cohomology theory for Lie 2-algebras and Lie 2-groups." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/45/45131/tde-15022019-084657/.
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In this thesis, we introduce a new cohomology theory associated to a Lie 2-algebras and a new cohomology theory associated to a Lie 2-group. These cohomology theories are shown to extend the classical cohomology theories of Lie algebras and Lie groups in that their second groups classify extensions. We use this fact together with an adapted van Est map to prove the integrability of Lie 2-algebras anew.Nesta tese, nós introduzimos uma nova teoria de cohomologia associada às 2-álgebras de Lie e uma nova teoria de cohomologia associada aos 2-grupos de Lie. Prova-se que estas teorias de cohomologia estendem as teorias de cohomologia clássicas de álgebras de Lie e grupos de Lie em que os seus segundos grupos classificam extensões. Finalmente, usaremos estos fatos junto com um morfismo de van Est adaptado para encontrar uma nova prova da integrabilidade das 2-álgebras de Lie.
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Bowman, K. "A lattice theory for algebras." Thesis, Lancaster University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234611.
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Watts, Gerard Marcel Tannerie. "Extended algebras in conformal field theory." Thesis, University of Cambridge, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.277913.
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Menard, Etienne. "Algèbres amassées associées aux variétés de Richardson ouvertes : un algorithme de calcul de graines initiales." Thesis, Normandie, 2021. http://www.theses.fr/2021NORMC211.
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Les algèbres amassées sont des anneaux commutatifs intègres avec une structure combinatoire particulière.Cette structure consiste en la donnée d’une famille de graines, liées entre elles par une opération appelée mutation.Chaque graine est composée de deux parties : un amas et un carquois.Les variétés de Richardson ouvertes sont des strates de la variété de drapeaux associée à un groupe linéairealgébrique de type simplement lacé. Elles sont l’intersection de cellules de Schubert respectivement à deux sous-groupes de Borel opposés. Dans [Lec16], une sous-algèbre amassée de rang maximal sur l’anneau de coordonnéesd’une variété de Richardson ouverte a été construite et cette sous-algèbre est conjecturée être égale à l’anneauentier. La construction de cette algèbre amassée provient d’une catégorie de Frobenius C v,w de modules surl’algèbre préprojective, définie comme intersection de deux catégories C w et C v déjà étudiées par Geiss, Leclerc,Schröer et Buan, Iyama, Reiten et Scott. Le lien entre les algèbres amassées et les structures amassées est donnépar le caractère d’amas défini dans [GLS06].Dans cette thèse, nous construisons un algorithme qui, étant donné les paramètres définissant une variété deRichardson ouverte, construit un module rigide maximal explicite de la catégorie de Frobenius associée et soncarquois. Cet algorithme a pour donnée de départ la graine initiale pour la structure amassée sur C w définiepar un représentant w d’un élément w du groupe de Weyl. Par le biais d’une suite de mutations déterminéecombinatoirement, on obtient à partir de la graine initiale un module rigide maximal de C w qui, à suppressionde certains facteurs directs près, est un module rigide maximal de C v,w . De plus le sous-carquois du carquoismuté est exactement le carquois de l’algèbre d’endomorphisme du module rigide maximal de C v,w donnant alorsla description complète d’une graine initiale pour la structure amassée de C v,wCluster algebras are integral domains with a particular combinatorial structure. This structure consists in thedata of a family of seeds linked together by an operation called mutation. Each seed consists in two parts : acluster and a quiver.Richardson open varieties are some strata of the flag variety associated to a simple linear algebraic groupof simply-laced type. These are the intersection of Schubert cells with respect to two opposite Borel subgroups.In [Lec16] a cluster subalgebra of maximal rank on the coordinate ring of an open Richardson variety has beenconstructed and this subalgebra is conjectured to be equal to the whole ring. The construction of this clusteralgebra comes from a Frobenius category C v,w of modules over the preprojective algebra, defined as the intersectionof two categories C w and C v already studied by Geiss, Leclerc, Schröer and Buan, Iyama, Reiten and Scott. Thebond between cluster algebras and cluster structures is given by the cluster character defined in [GLS06].In this thesis we build an algorithm which, given the parameters defining a Richardson open variety, computean explicit maximal rigid module of the associated Frobenius category and its quiver. This algorithm has aninitial seed for the cluster structure on C w defined by a representative w of an element w of the Weyl group as astarting datum. By a combinatorially defined sequence of mutation on this initial seed we obtain a maximal rigidmodule of C w which is, up to deletion of some direct summands is a maximal rigid module of C v,w . In addition,the subquiver of the mutated quiver is exactly the quiver of the endomorphism algebra of the C v,w -maximal rigidmodule, giving then the complete description of an initial seed for the cluster structure on C v,w
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Apedaile, Thomas J. "Computational Topics in Lie Theory and Representation Theory." DigitalCommons@USU, 2014. https://digitalcommons.usu.edu/etd/2156.
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The computer algebra system Maple contains a basic set of commands for working with Lie algebras. The purpose of this thesis was to extend the functionality of these Maple packages in a number of important areas. First, programs for dening multiplication in several types of Cayley algebras, Jordan algebras and Cliord algebras were created to allow users to perform a variety of calculations. Second, commands were created for calculating some basic properties of nite-dimensional representations of complex semisimple Lie algebras. These commands allow one to identify a given representation as direct sum of irreducible subrepresentations, each one identied by an invariant highest weight. Third, creating an algorithm to calculate the Lie bracket for Vinberg's symmetric construction of Freudenthal's Magic Square allowed for a uniform construction of all ve exceptional Lie algebras. Maple examples and tutorials are provided to illustrate the implementation and use of the algebras now available in Maple as well as the tools for working with Lie algebra representations.
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Boddington, Paul. "No-cycle algebras and representation theory." Thesis, University of Warwick, 2004. http://wrap.warwick.ac.uk/3482/.
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In the first half of this dissertation we study certain quotient algebras of preprojective algebras called no-cycle algebras N. These are studied via one-cycle algebras, which are introduced here. Results include detailed combinatorial information on N, and in certain special cases a presentation for N as a quiver with relations. In the second half we consider deformations of coordinate algebras of Kleinian singularities. Results include an explicit presentation for the deformations of a type D singularity. These two themes are tied together at the end by some mainly speculative comments about the role the various objects studied have to play in representation theory.
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King, Oliver. "The representation theory of diagram algebras." Thesis, City University London, 2014. http://openaccess.city.ac.uk/5915/.
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In this thesis we study the modular representation theory of diagram algebras, in particular the Brauer and partition algebras, along with a brief consideration of the Temperley-Lieb algebra. The representation theory of these algebras in characteristic zero is well understood, and we show that it can be described through the action of a reflection group on the set of simple modules (a result previously known for the Temperley-Lieb and Brauer algebras). By considering the action of the corresponding affine reflection group, we give a characterisation of the (limiting) blocks of the Brauer and partition algebras in positive characteristic. In the case of the Brauer algebra, we then show that simple reflections give rise to non-zero decomposition numbers. We then restrict our attention to a particular family of Brauer and partition algebras, and use the block result to determine the entire decomposition matrix of the algebras therein.
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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.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.
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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Fialowski, Alice, Michael Penkava, and fialowsk@cs elte hu. "Deformation Theory of Infinity Algebras." ESI preprints, 2000. ftp://ftp.esi.ac.at/pub/Preprints/esi906.ps.
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Frédéric, Holweck. "Lieu singulier des variétés duales : approche géométrique et applications aux variétés homogènes." Phd thesis, Université Paul Sabatier - Toulouse III, 2004. http://tel.archives-ouvertes.fr/tel-00737441.
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On doit à Friedrich Knop un étonnant théorème qui établit un lien entre algèbres de Lie simples de type A-D-E, et singularités simples de même type. Le résultat est le suivant : on considère la projectivisation de l'orbite de plus haut poids pour l'action adjointe d'un groupe de Lie simple sur son algèbre de Lie (une telle variété est appelée variété adjointe). Il existe alors un hyperplan tangent à l'orbite ayant un unique point singulier du même type que celui de l'algèbre de Lie. Ce théorème est le point de départ de nos travaux. Afin de mieux comprendre ce lien, nous étudions la géométrie des variétés duales des variétés adjointes. Dans le premier chapitre nous prouvons une version duale du théorème de Knop. Notre théorème permet d'obtenir le discriminant d'une singularité simple à partir de la duale de la variété adjointe. L'hyperplan considéré par Knop s'interprète alors comme un point très singulier de la duale. Dans le deuxième chapitre nous considérons le lieu singulier de la duale pour une variétés projective lisse. Nous montrons que l'existence de certaines strates de dimensions maximales équivaut à l'existence de section hyperplane de la variété d'origine admettant des points singuliers d'un type donné. Nous insistons alors sur l'importance de deux strates qui ont un sens géométrique : la duale de la variété des tangentes et la duale de la variété des sécantes. Enfin dans un dernier chapitre nous appliquons ces résultats à l'étude de la normalité des duales des variétés homogènes.
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Minets, Alexandre. "Algèbres de Hall cohomologiques et variétés de Nakajima associées a des courbes." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS228/document.
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Pour toute courbe projective lisse C et théorie homologique orientée de Borel-Moore libre A, on construit un produit associatif de type Hall sur les A-groupes du champ de modules des faisceaux de Higgs de torsion sur C.On montre que l'algèbre AHa0C qu'on obtient admet une présentation de battage naturelle, qui est fidèle dans le cas où A est l'homologie de Borel-Moore usuelle.On introduit de plus les espaces de modules des triplets stables M(d,n), fortement inspirés par les variétés de carquois de Nakajima.Ces espaces de modules sont des variétés lisses symplectiques, et admettent une autre caractérisation comme les espaces de modules de faisceaux sans torsion stables encadrés sur P(T*C)$.De plus, on munit leurs A-groupes avec une action de AHa0C, qui généralise les opérateurs de modification ponctuelle de Nakajima sur l'homologie des schémas de Hilbert de T*CFor a smooth projective curve C and a free oriented Borel-Moore homology theory A, we construct a Hall-like associative product on the A-theory of the moduli stack of Higgs torsion sheaves on C.We show that the resulting algebra AHa0C admits a natural shuffle presentation, and prove it is faithful when A is replaced with usual Borel-Moore homology groups.We also introduce moduli spaces of stable triples M(d,n), heavily inspired by Nakajima quiver varieties.These moduli spaces are shown to be smooth symplectic varieties, which admit another characterization as moduli of framed stable torsion-free sheaves on P(T*C).Moreover, we equip their A-theory with an AHa0C-action, which generalizes Nakajima's raising operators on the homology of Hilbert schemes of points on T*C
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Nornes, Nils Melvær. "Partial Orders in Representation Theory of Algebras." Thesis, Norwegian University of Science and Technology, Department of Mathematical Sciences, 2008. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-9689.
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In this paper we investigate some partial orders used in representation theory of algebras. Let $K$ be a commutative ring, $Lambda$ a finitely generated $K$-algebra and $d$ a natural number. We then study partial orders on the set of isomorphism classes of $Lambda$-modules of length $d$. The orders degeneration, virtual degeneration and hom-order are discussed. The main purpose of the paper is to study the relation $leq_n$ constructed by considering the ranks of $ntimes n$-matrices over $Lambda$ as $K$-endomorphisms on $M^n$ for a $Lambda$-module $M$. We write $Mleq_n N$ when for any $ntimes n$-matrix the rank with respect to $M$ is greater than or equal to the rank with respect to $N$. We study these relations for various algebras and determine when $leq_n$ is a partial order.
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Speyer, Liron. "Representation theory of Khovanov-Lauda-Rouquier algebras." Thesis, Queen Mary, University of London, 2015. http://qmro.qmul.ac.uk/xmlui/handle/123456789/9114.
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This thesis concerns representation theory of the symmetric groups and related algebras. In recent years, the study of the “quiver Hecke algebras”, constructed independently by Khovanov and Lauda and by Rouquier, has become extremely popular. In this thesis, our motivation for studying these graded algebras largely stems from a result of Brundan and Kleshchev – they proved that (over a field) the KLR algebras have cyclotomic quotients which are isomorphic to the Ariki–Koike algebras, which generalise the Hecke algebras of type A, and thus the group algebras of the symmetric groups. This has allowed the study of the graded representation theory of these algebras. In particular, the Specht modules for the Ariki–Koike algebras can be graded; in this thesis we investigate graded Specht modules in the KLR setting. First, we conduct a lengthy investigation of the (graded) homomorphism spaces between Specht modules. We generalise the rowand column removal results of Lyle and Mathas, producing graded analogues which apply to KLR algebras of arbitrary level. These results are obtained by studying a class of homomorphisms we call dominated. Our study provides us with a new result regarding the indecomposability of Specht modules for the Ariki–Koike algebras. Next, we use homomorphisms to produce some decomposability results pertaining to the Hecke algebra of type A in quantum characteristic two. In the remainder of the thesis, we use homogeneous homomorphisms to study some graded decomposition numbers for the Hecke algebra of type A. We investigate graded decomposition numbers for Specht modules corresponding to two-part partitions. Our investigation also leads to the discovery of some exact sequences of homomorphisms between Specht modules.
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Giroux, Yves. "Degenerate enveloping algebras of low-rank groups." Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=74026.
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Jordan, Alex. "A super version of Zhu's theorem /." Connect to title online (Scholars' Bank) Connect to title online (ProQuest), 2008. http://hdl.handle.net/1794/8283.
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Thesis (Ph. D.)--University of Oregon, 2008.Typescript. Includes vita and abstract. Includes bibliographical references (leaves 40-41). Also available online in Scholars' Bank; and in ProQuest, free to University of Oregon users.
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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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Jacoby, Adam Michael. "ON REPRESENTATION THEORY OF FINITE-DIMENSIONAL HOPF ALGEBRAS." Diss., Temple University Libraries, 2017. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/433432.
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MathematicsPh.D.
Representation theory is a field of study within abstract algebra that originated around the turn of the 19th century in the work of Frobenius on representations of finite groups. More recently, Hopf algebras -- a class of algebras that includes group algebras, enveloping algebras of Lie algebras, and many other interesting algebras that are often referred to under the collective name of ``quantum groups'' -- have come to the fore. This dissertation will discuss generalizations of certain results from group representation theory to the setting of Hopf algebras. Specifically, our focus is on the following two areas: Frobenius divisibility and Kaplansky's sixth conjecture, and the adjoint representation and the Chevalley property.
Temple University--Theses
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Amantini, Andrea. "Fraïssé-Hrushovski predimensions on nilpotent Lie algebras." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät II, 2011. http://dx.doi.org/10.18452/16345.
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In dieser Arbeit wird das Fraïssé-Hrushowskis Amalgamationsverfahren in Zusammenhang mit nilpotenten graduierten Lie Algebren über einem endlichen Körper untersucht. Die Prädimensionen die in der Konstruktion auftauchen sind mit dem gruppentheoretischen Begriff der Defizienz zu vergleichen, welche auf homologische Methoden zurückgeführt werden kann. Darüber hinaus wird die Magnus-Lazardsche Korrespondenz zwischen den oben genannten Lie Algebren und nilpotenten Gruppen von Primzahl-Exponenten beschrieben. Dabei werden solche Gruppen durch die Baker-Haussdorfsche Formel in den entsprechenden Algebren definierbar interpretiert. Es wird eine omega-stabile Lie Algebra von Nilpotenzklasse 2 und Morleyrang omega + omega erhalten, indem man eine unkollabierte Version der von Baudisch konstruierten "new uncountably categorical group" betrachtet. Diese wird genau analysiert. Unter anderem wird die Unabhängigkeitsrelation des Nicht-Gabelns durch die Konfiguration des freien Amalgams charakterisiert. Mittels eines induktiven Ansatzes werden die Grundlagen entwickelt, um neue Prädimensionen für Lie Algebren der Nilpotenzklassen größer als zwei zu schaffen. Dies erweist sich als wesentlich schwieriger als im Fall 2. Wir konzentrieren uns daher auf die Nilpotenzklasse 3, als Induktionsbasis des oben genannten Prozesses. In diesem Fall wird die Invariante der Defizienz auf endlich erzeugte Lie Algebren adaptiert. Erstes Hauptergebnis der Arbeit ist der Nachweis dass diese Definition zu einem vernüftigen Begriff selbst-genügender Erweiterungen von Lie Algebren führt und sehr nah einer gewünschten Prädimension im Hrushovskischen Sinn ist. Wir zeigen – als zweites Hauptergebnis – ein erstes Amalgamationslemma bezüglich selbst-genügender Einbettungen.In this work, the so called Fraïssé-Hrushowski amalgamation is applied to nilpotent graded Lie algebras over the p-elements field with p a prime. We are mainly concerned with the uncollapsed version of the original process. The predimension used in the construction is compared with the group theoretical notion of deficiency, arising from group Homology. We also describe in detail the Magnus-Lazard correspondence, to switch between the aforementioned Lie algebras and nilpotent groups of prime exponent. In this context, the Baker-Hausdorff formula allows such groups to be definably interpreted in the corresponding algebras. Starting from the structures which led to Baudisch’ new uncountably categorical group, we obtain an omega-stable Lie algebra of nilpotency class 2, as the countable rich Fraïssé limit of a suitable class of finite Lie algebras. We study the theory of this structure in detail: we show its Morley rank is omega+omega and a complete description of non-forking independence is given, in terms of free amalgams. In a second part, we develop a new framework for the construction of deficiency-predimensions among graded Lie algebras of nilpotency class higher than 2. This turns out to be considerably harder than the previous case. The nil-3 case in particular has been extensively treated, as the starting point of an inductive procedure. In this nilpotency class, our main results concern a suitable deficiency function, which behaves for many aspects like a Hrushovski predimension. A related notion of self-sufficient extension is given. We also prove a first amalgamation lemma with respect to self-sufficient embeddings.
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Colligan, Mark. "Some topics in the representation theory of Brauer algebras." Thesis, University of Kent, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.587556.
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This thesis is concerned with the representation theory of the Brauer algebra over an algebraically closed field of arbitrary characteristic. There are two main themes, given as follows. Firstly, we describe some classes of simple modules for the Brauer algebras with parameters ±2. Secondly, we derive a combinatorial basis of the vector space of homomorphisms from one permutation module to another. We do the same for the vector space of homomorphisms from a permutation module to a cell module. Using these bases, we show that every homomorphism from a permutation module to a cell module factors through the permutation module whose label agrees with that of the cell module.
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Banjo, Elizabeth. "Representation theory of algebras related to the partition algebra." Thesis, City University London, 2013. http://openaccess.city.ac.uk/2360/.
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The main objective of this thesis is to determine the complex generic representation theory of the Juyumaya algebra. We do this by showing that a certain specialization of this algebra is isomorphic to the small ramified partition algebra, introduced by Martin (the representation theory of which is computable by a combination of classical and category theoretic techniques). We then use this result and general arguments of Cline, Parshall and Scott to prove that the Juyumaya algebra En(x) over the complex field is generically semisimple for all n 2 N. The theoretical background which will facilitate an understanding of the construction process is developed in suitable detail. We also review a result of Martin on the representation theory of the small ramified partition algebra, and fill in some gaps in the proof of this result by providing proofs to results leading to it.
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Hussein, Ahmed Baqer. "On the representation theory of the Fuss-Catalan algebras." Thesis, University of Leeds, 2017. http://etheses.whiterose.ac.uk/17949/.
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Throughout this thesis, we study the representation theory of the Fuss-Catalan algebras, $FC_{2,n}(a, b)$. We prove that these algebras are cellular and we define their cellular basis. In addition, we prove that they form a tower of recollement, and hence, they are quasi-hereditary. By calculating the Gram determinants of certain cell modules for the Fuss-Catalan algebras, we determine when these algebras are not semisimple. Finally, we end with defining homomorphisms between specified cell modules.
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Bulgakova, Daria. "Some aspects of representation theory of walled Brauer algebras." Thesis, Aix-Marseille, 2020. http://www.theses.fr/2020AIXM0022.
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L'algèbre de Brauer murée est une algèbre unitaire associative. Il s’agit d’une algèbre de diagramme engendré par des diagrammes «murés» particuliers. Cette algèbre peut être définie par des générateurs et des relations. Dans le premier chapitre de la thèse, nous construisons la forme normale de l'algèbre de Brauer murée - un ensemble de monômes de base (mots) dans les générateurs. Nous introduisons une modification “ordonnée” du fameux lemme du diamant de Bergman, à savoir, nous présentons un ensemble de règles qui, étant appliquées dans un certain ordre, permet de réduire tout monôme dans les générateurs à un élément de la forme normale. Nous appliquons ensuite la forme normale pour calculer la fonction génératrice du nombre de mots avec une longueur minimale donnée.Une procédure de fusion donne une construction de la famille maximale d'idempotents orthogonaux minimaux par paire dans l'algèbre et, par conséquent, fournit un moyen de comprendre les bases dans les représentations irréductibles. Nous construisons la procédure de fusion pour l'algèbre de Brauer murée, à savoir, tous les idempotents primitifs est trouvé par les évaluations consécutives de fonction rationnelle en plusieurs variables.Dans le deuxième chapitre, nous étudions le produit tensoriel mixte des représentations fondamentales tridimensionnelles de l'algèbre de Hopf U_q sl(2|1). L'un des principaux résultats consiste à établir des formules explicites pour la décomposition des produits tensoriels de tout module de U_q sl(2|1) simple ou projectif avec les modules générateurs. Un autre résultat important consiste à décomposer le produit tensoriel mixte en un bimoduleThe walled Brauer algebra is an associative unital algebra. It is a diagram algebra spanned by particular ‘walled’ diagrams with multiplication given by concatenation. This algebra can be defined in terms of generators, obeying certain relations. In the first part of the dissertation we construct the normal form of the walled Brauer algebra - a set of basis monomials (words) in generators. This set is constructed with the aid of the so-called Bergman’s diamond lemma: we present a set of rules which allows one to reduce any monomial in generators to an element from the normal form. We then apply the normal form to calculate the generating function for the numbers of words with a given minimal length.A fusion procedure gives a construction of the maximal family of pairwise orthogonal minimal idempotents in the algebra, and therefore, provides a way to understand bases in the irreducible representations. As a main result of the second part we construct the fusion procedure for the walled Brauer algebra and show that all primitive idempotents can be found by evaluating a rational function in several variables. In the third part we study the mixed tensor product of three-dimensional fundamental representations of the Hopf algebra U_q sl(2|1). One of the main results consists in the establishing of the explicit formulae for the decomposition of tensor products of any simple or any projective U_q sl(2|1)-module with the generating modules. Another important outcome consists in decomposing the mixed tensor product as a bimodule
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Hmaida, Mufida Mohamed A. "Representation theory of algebras related to the bubble algebra." Thesis, University of Leeds, 2016. http://etheses.whiterose.ac.uk/15987/.
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In this thesis we study several algebras which are related to the bubble algebra, including the bubble algebra itself. We introduce a new class of multi-parameter algebras, called the multi-colour partition algebra $ P_{n,m} ( \breve{\delta} )$, which is a generalization of both the partition algebra and the bubble algebra. We also define the bubble algebra and the multi-colour symmetric groupoid algebra as sub-algebras of the algebra $ P_{n,m} ( \breve{\delta} ) $. We investigate the representation theory of the multi-colour symmetric groupoid algebra $ \F S_{n,m} $. We show that $ \F S_{n,m} $ is a cellular algebra and it is isomorphic to the generalized symmetric group algebra $ \F \mathbb{Z}_m \wr S_n $ when $ m $ is invertible and $ \F $ is an algebraically closed field. We then prove that the algebra $ P_{n,m} ( \breve{\delta} ) $ is also a cellular algebra and define its cell modules. We are therefore able to classify all the irreducible modules of the algebra $ P_{n,m} ( \breve{\delta} ) $. We also study the semi-simplicity of the algebra $ P_{n,m} ( \breve{\delta} ) $ and the restriction rules of the cell modules to lower rank $ n $ over the complex field. The main objective of this thesis is to solve some open problems in the representation theory of the bubble algebra $ T_{n,m} ( \breve{\delta} ) $. The algebra $ T_{n,m} ( \breve{\delta} ) $ is known to be cellular. We use many results on the representation theory of the Temperley-Lieb algebra to compute bases of the radicals of cell modules of the algebra $ T_{n,m} ( \breve{\delta} ) $ over an arbitrary field. We then restrict our attention to study representations of $ T_{n,m} ( \breve{\delta} ) $ over the complex field, and we determine the entire Loewy structure of cell modules of the algebra $ T_{n,m} ( \breve{\delta} ) $. In particular, the main theorem is Theorem 5.41.
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Dehling, Malte [Verfasser]. "Symmetric Homotopy Theory for Operads and Weak Lie 3-Algebras / Malte Dehling." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2021. http://d-nb.info/1225121639/34.
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Thiffeault, Jean-Luc. "Classification, Casimir invariants, and stability of lie-poisson systems /." Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.
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Bellamy, Gwyn. "Generalized Calogero-Moser spaces and rational Cherednik algebras." Thesis, University of Edinburgh, 2010. http://hdl.handle.net/1842/4733.
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The subject of this thesis is the interplay between the geometry and the representation theory of rational Cherednik algebras at t = 0. Exploiting this relationship, we use representation theoretic techniques to classify all complex re ection groups for which the geometric space associated to a rational Cherednik algebra, the generalized Calogero-Moser space, is singular. Applying results of Ginzburg-Kaledin and Namikawa, this classification allows us to deduce a (nearly complete) classification of those symplectic reflection groups for which there exist crepant resolutions of the corresponding symplectic quotient singularity. Then we explore a particular way of relating the representation theory and geometry of a rational Cherednik algebra associated to a group W to the representation theory and geometry of a rational Cherednik algebra associated to a parabolic subgroup of W. The key result that makes this construction possible is a recent result of Bezrukavnikov and Etingof on completions of rational Cherednik algebras. This leads to the definition of cuspidal representations and we show that it is possible to reduce the problem of studying all the simple modules of the rational Cherednik algebra to the study of these nitely many cuspidal modules. We also look at how the Etingof-Ginzburg sheaf on the generalized Calogero-Moser space can be "factored" in terms of parabolic subgroups when it is restricted to particular subvarieties. In particular, we are able to confirm a conjecture of Etingof and Ginzburg on "factorizations" of the Etingof-Ginzburg sheaf. Finally, we use Clifford theoretic techniques to show that it is possible to deduce the Calogero-Moser partition of the irreducible representations of the complex reflection groups G(m; d; n) from the corresponding partition for G(m; 1; n). This confirms, in the case W = G(m; d; n), a conjecture of Gordon and Martino relating the Calogero-Moser partition to Rouquier families for the corresponding cyclotomic Hecke algebra.
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Gordon, Iain. "Representation theory of quantised function algebras at roots of unity." Thesis, Connect to electronic version, 1998. http://hdl.handle.net/1905/177.
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Spencer, Matthew. "The representation theory of Iwahori-Hecke algebras with unequal parameters." Thesis, Queen Mary, University of London, 2014. http://qmro.qmul.ac.uk/xmlui/handle/123456789/8644.
Full textAbstract:
The Iwahori-Hecke algebras of finite Coxeter groups play an important role in many areas of mathematics. In this thesis we study the representation theory of the Iwahori-Hecke algebras of the Coxeter groups of type Bn and F4, in the unequal parameter case. We denote these algebras HQ and KQ respectively. This follows on from work done by Dipper, James, Murphy and Norton. We are interested in the Iwahori-Hecke algebras of type Bn and F4 since these are the only cases, apart from the dihedral groups, where the Coxeter generators lie in different conjugacy classes, and therefore the Iwahori-Hecke algebra can have unequal parameters. There are two parameters associated with these algebras, Q and q. Norton dealt with the case Q = q = 0, whilst Dipper, James and Murphy addressed the case q 6= 0 in type Bn. In this thesis we look at the case Q 6= 0; q = 0. We begin by constructing the simple modules for HQ, then compute the Ext quiver and find the blocks of HQ. We continue by observing that there is a natural embedding of the algebra of type n 1 in the algebra of type n, and this gives rise to the notion of an induced module. We look at the structure of the induced module associated with a given simple HQ-module. Here we are able to construct a composition series for the induced module and show that in a particular case the induced modules are self-dual. Finally, we look at KQ and find that the representation theory is related to representation theory of the Iwahori-Hecke algebra of type B3. Using this relationship we are able to construct the simple modules for KQ and begin the analysis of the Ext quiver.