Sejam K um corpo algebricamente fechado, A uma K-álgebra básica conexa de dimensão finita sobre K e ê=(e_1,e_2,... ,e_n) um conjunto completo de idempotentes ortogonais, primitivos e ordenados de A. O conjunto dos módulos estandares é o conjunto Delta ={ D_1, ..., D_n }, onde D_i é o quociente maximal do A-módulo projetivo P_i com fatores de composição simples S_j, com j\\leq i, F(Delta) é a subcategoria plena de mod A dos módulos têm uma Delta-filtração. Se A_A esta em F(Delta) diz-se que A é uma álgebra estandarmente estratificada. Se, além disso, para cada elemento em Delta vale que End_A(D_i) é isomorfo a K diz-se que A é uma álgebra álgebra quase-hereditária. Nesta dissertação estudamos as propriedades de F(Delta), especialmente quando A é estandarmente estratificada, e algumas condições necessárias e suficientes para que A seja quase-hereditária. / Let K be an algebraically closed field, A a basic, connected, finite dimensional K-algebra and ê=(e_1,e_2,...,e_n) a complete set of ordered primitive orthogonal idempotents of A. The set of standard modules is the set Delta={D_1, ..., D_n}, where D_i is the maximal factor submodule of P_i whose composition factors are isomorphic to S_j, for j\\leq i. We denote by F(Delta) the full subcategory of mod A containing the modules which are filtered by modules in Delta. If iA_A is in F(Delta) we say that A is standardly stratified. Moreover, if End_A(D_i) is isomorphic with K, for each element in Delta we say that A is quasi hereditary. In this work we study the properties of the category F(Delta), especially when A is stardardly stratified, and some necessary and sufficient conditions to A be quasi hereditary.

Nesta tese estudamos o conceito de grau de um morfismo irredutível em ${m mod}A$ relacionado ao conceito de teoria de partições pós-projetiva e pré-injetiva de uma álgebra de artin $A$. Introduzimos o conceito de grau de um morfismo irredutível em relação a uma categoria ${\\mathfrak D}$ de ${m ind}A$ e estudamos o caso em que ${\\mathfrak D}$ é um elemento da partição ${\\bf P_0}, \\cdots, {\\bf P_{\\infty}}$. Dentro do contexto de grau de um irredutível em relação a uma subcategoria resolvemos um problema proposto por Chaio, Le meur e Trepode em \\cite. Utilizando as partições pós-projetiva e pré-injetiva obtemos outra demonstração para a caracterização de álgebras de tipo finito obtida em \\cite e obtemos uma caracterização semelhante para subcategorias de módulos $\\Delta$-bons de tipo finito de ${m mod}A$ tal que $A$ é uma álgebra quasi-hereditária. Também utilizamos a teoria de partições para provar que, dada uma álgebra quasi-hereditária $A$ e ${\\cal F}(\\Delta) \\subseteq {m mod}A$, se $({m rad}_{\\Delta}^{\\infty})^2=0$ então ${\\cal F}(\\Delta)$ é de tipo finito. / In this thesis we analyse the concept of the degree of an irreducible morphism associated to the theory of postprojective and preinjective partitions. We introduce the idea of the degree of an irreducible morphism with respect to a subcategory ${\\mathfrak D}$ and we study the case in which ${\\mathfrak D}$ is an element of the postprojective partition ${\\bf P_0}, \\cdots, {\\bf P_{\\infty}}$. By using the concept of the degree of an irreducible morphism with respect to a subcategory ${\\mathfrak D}$ we present a solution to a problem recently proposed by Chaio, Le Meur and Trepode in \\cite. We also use the theory of postprojective and preprojective partitions to give another proof to the characterization of finite type algebras obtained by Chaio and Liu in \\cite and we apply similar techniques to obtain a characterization of finite type ${\\cal F}(\\Delta)$ subcategories where ${\\cal F}(\\Delta)$ is the subcategory of $\\Delta$-good modules of the category of finitely generated modules over a quasi-hereditary algebra. We also prove that given a quasi-hereditary algebra $A$ and ${\\cal F}(\\Delta) \\subseteq {m mod}A$, if $({m rad}_{\\Delta}^{\\infty})^2=0$ then ${\\cal F}(\\Delta)$ is of finite type.

Nesta tese estudamos o conceito de grau de um morfismo irredutível em ${m mod}A$ relacionado ao conceito de teoria de partições pós-projetiva e pré-injetiva de uma álgebra de artin $A$. Introduzimos o conceito de grau de um morfismo irredutível em relação a uma categoria ${\\mathfrak D}$ de ${m ind}A$ e estudamos o caso em que ${\\mathfrak D}$ é um elemento da partição ${\\bf P_0}, \\cdots, {\\bf P_{\\infty}}$. Dentro do contexto de grau de um irredutível em relação a uma subcategoria resolvemos um problema proposto por Chaio, Le meur e Trepode em \\cite. Utilizando as partições pós-projetiva e pré-injetiva obtemos outra demonstração para a caracterização de álgebras de tipo finito obtida em \\cite e obtemos uma caracterização semelhante para subcategorias de módulos $\\Delta$-bons de tipo finito de ${m mod}A$ tal que $A$ é uma álgebra quasi-hereditária. Também utilizamos a teoria de partições para provar que, dada uma álgebra quasi-hereditária $A$ e ${\\cal F}(\\Delta) \\subseteq {m mod}A$, se $({m rad}_{\\Delta}^{\\infty})^2=0$ então ${\\cal F}(\\Delta)$ é de tipo finito. / In this thesis we analyse the concept of the degree of an irreducible morphism associated to the theory of postprojective and preinjective partitions. We introduce the idea of the degree of an irreducible morphism with respect to a subcategory ${\\mathfrak D}$ and we study the case in which ${\\mathfrak D}$ is an element of the postprojective partition ${\\bf P_0}, \\cdots, {\\bf P_{\\infty}}$. By using the concept of the degree of an irreducible morphism with respect to a subcategory ${\\mathfrak D}$ we present a solution to a problem recently proposed by Chaio, Le Meur and Trepode in \\cite. We also use the theory of postprojective and preprojective partitions to give another proof to the characterization of finite type algebras obtained by Chaio and Liu in \\cite and we apply similar techniques to obtain a characterization of finite type ${\\cal F}(\\Delta)$ subcategories where ${\\cal F}(\\Delta)$ is the subcategory of $\\Delta$-good modules of the category of finitely generated modules over a quasi-hereditary algebra. We also prove that given a quasi-hereditary algebra $A$ and ${\\cal F}(\\Delta) \\subseteq {m mod}A$, if $({m rad}_{\\Delta}^{\\infty})^2=0$ then ${\\cal F}(\\Delta)$ is of finite type.

Sejam K um corpo algebricamente fechado, A uma K-álgebra básica conexa de dimensão finita sobre K e ê=(e_1,e_2,... ,e_n) um conjunto completo de idempotentes ortogonais, primitivos e ordenados de A. O conjunto dos módulos estandares é o conjunto Delta ={ D_1, ..., D_n }, onde D_i é o quociente maximal do A-módulo projetivo P_i com fatores de composição simples S_j, com j\\leq i, F(Delta) é a subcategoria plena de mod A dos módulos têm uma Delta-filtração. Se A_A esta em F(Delta) diz-se que A é uma álgebra estandarmente estratificada. Se, além disso, para cada elemento em Delta vale que End_A(D_i) é isomorfo a K diz-se que A é uma álgebra álgebra quase-hereditária. Nesta dissertação estudamos as propriedades de F(Delta), especialmente quando A é estandarmente estratificada, e algumas condições necessárias e suficientes para que A seja quase-hereditária. / Let K be an algebraically closed field, A a basic, connected, finite dimensional K-algebra and ê=(e_1,e_2,...,e_n) a complete set of ordered primitive orthogonal idempotents of A. The set of standard modules is the set Delta={D_1, ..., D_n}, where D_i is the maximal factor submodule of P_i whose composition factors are isomorphic to S_j, for j\\leq i. We denote by F(Delta) the full subcategory of mod A containing the modules which are filtered by modules in Delta. If iA_A is in F(Delta) we say that A is standardly stratified. Moreover, if End_A(D_i) is isomorphic with K, for each element in Delta we say that A is quasi hereditary. In this work we study the properties of the category F(Delta), especially when A is stardardly stratified, and some necessary and sufficient conditions to A be quasi hereditary.

<p>This thesis, consisting of three papers and a summary, studies properties of stratified algebras and representations of Lie superalgebras.</p><p>In Paper I we give a characterization when the Ringel dual of an SSS-algebra is properly stratified.</p><p>We show that for an SSS-algebra, whose Ringel dual is properly stratified, there is a (generalized) tilting module which allows one to compute the finitistic dimension of the SSS-algebra, and moreover, it gives rise to a new covariant Ringel-type duality.</p><p>In Paper II we give a characterization of standardly stratified algebras in terms of certain filtrations of (left or right) projective modules, generalizing the corresponding theorem of V. Dlab. We extend the notion of Ringel duality to standardly stratified algebras and estimate their finitistic dimension in terms of endomorphism algebras of standard modules.</p><p>Paper III deals with the queer Lie superalgebra and the corresponding BGG-category O. We show that the typical blocks correspond to standardly stratified algebras, and we generalize Kostant's Theorem to the queer Lie superalgebra.</p>

This thesis, consisting of three papers and a summary, studies properties of stratified algebras and representations of Lie superalgebras. In Paper I we give a characterization when the Ringel dual of an SSS-algebra is properly stratified. We show that for an SSS-algebra, whose Ringel dual is properly stratified, there is a (generalized) tilting module which allows one to compute the finitistic dimension of the SSS-algebra, and moreover, it gives rise to a new covariant Ringel-type duality. In Paper II we give a characterization of standardly stratified algebras in terms of certain filtrations of (left or right) projective modules, generalizing the corresponding theorem of V. Dlab. We extend the notion of Ringel duality to standardly stratified algebras and estimate their finitistic dimension in terms of endomorphism algebras of standard modules. Paper III deals with the queer Lie superalgebra and the corresponding BGG-category O. We show that the typical blocks correspond to standardly stratified algebras, and we generalize Kostant's Theorem to the queer Lie superalgebra.

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第21535号 / 理博第4442号 / 新制||理||1638(附属図書館) / 京都大学大学院理学研究科数学・数理解析専攻 / (主査)准教授 加藤 周, 教授 重川 一郎, 教授 並河 良典 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

Quasi-hereditary algebras are an important class of algebras with many appli-cations in representation theory, most notably the representation theory of semi-simple complex Lie-algebras. Such algebras sometimes admit an exact Borel sub-algebra, that is a subalgebra satisfying similar formal properties to the Borel sub-algebras from Lie theory. This thesis is divided into two parts. In the first part we classify quasi-hereditary algebras with two simple modules over perfect fields up to Morita equivalence, generalizing a similar result by Membrillo-Hernandez for thealgebraically closed case. In the second part, we take a poset X, a certain set M of constants, and a finite set ρ of paths in the Hasse-diagram of X and construct analgebra A(X, M, ρ) that generalizes the twisted double incidence algebras originally introduced by Deng and Xi. We provide necessary and sufficient conditions for this algebra to be quasi-hereditary when X is a tree, and we show that A(X, M, ρ) admits an exact Borel subalgebra when these conditions are satisfied. Following this, we compute the Ext-algebra of the standard modules of A(X, M, ρ).

Les algèbres cellulaires furent introduite par J.J. Graham et G.I. Lehrer en 1996. Elles forment une famille d’algèbres associatives de dimension finie définies en termes de « données cellulaires » satisfaisant certains axiomes. Ces données cellulaires, lorsqu’elles sont identifiées pour une certaine algèbre, permettent une construction explicite de tous ses modules simples, à isomorphisme près, et de leurs couvertures projectives. Dans ce mémoire, nous définissons ces algèbres cellulaires en introduisant progressivement chacun des éléments constitutifs d’une façon axiomatique. Deux autres familles d’algèbres associatives sont discutées, à savoir les algèbres quasihéréditaires et celles dont les modules forment une catégorie de plus haut poids. Ces familles furent introduites durant la même période de temps, au tournant des années quatre-vingtdix. La relation entre ces deux familles ainsi que celle entre elles et les algèbres cellulaires sont prouvées. / Cellular algebras were introduced by J.J. Graham and G.I. Lehrer in 1996. They are a class of finite-dimensional associative algebras defined in terms of a “cellular datum” satisfying some axioms. This cellular datum, when made explicit for a given associative algebra, allows for the explicit construction of all its simple modules, up to isomorphism, and of their projective covers. In this work, we define these cellular algebras by introducing each building block of the cellular datum in a fairly axiomatic fashion. Two other families of associative algebras are discussed, namely the quasi-hereditary algebras and those whose modules form a highest weight category. These families were introduced at about the same period. The relationships between these two, and between them and the cellular ones, are made explicit.