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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

The nonexistence of certain free pro-p extensions and capitulation in a family of dihedral extensions of Q /

Hubbard, David, January 1996 (has links)
Thesis (Ph. D.)--University of Washington, 1996. / Vita. Includes bibliographical references (leaves [47]-48).
42

Bourbaki ideals /

Whittle, Carrie A., January 1900 (has links)
Thesis (M.S.)--Missouri State University, 2008. / "August 2008." Includes bibliographical references (leaf 53). Also available online.
43

Drinfeld modules and their application to factor polynomials

Randrianarisoa, Tovohery Hajatiana 12 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Major works done in Function Field Arithmetic show a strong analogy between the ring of integers Z and the ring of polynomials over a nite eld Fq[T]. While an algorithm has been discovered to factor integers using elliptic curves, the discovery of Drinfeld modules, which are analogous to elliptic curves, made it possible to exhibit an algorithm for factorising polynomials in the ring Fq[T]. In this thesis, we introduce the notion of Drinfeld modules, then we demonstrate the analogy between Drinfeld modules and Elliptic curves. Finally, we present an algorithm for factoring polynomials over a nite eld using Drinfeld modules. / AFRIKAANSE OPSOMMING: 'n Groot deel van die werk wat reeds in funksieliggaam rekenkunde voltooi is toon 'n sterk verband tussen die ring van heelgetalle, Z; en die ring van polinome oor 'n eindige liggaam, F[T]: Terwyl daar alreeds 'n algoritme, wat gebruik maak van elliptiese kurwes, ontwerp is om heelgetalle te faktoriseer, het die ontdekking van Drinfeld modules, wat analoog is aan elliptiese kurwes, dit moontlik gemaak om 'n algoritme te konstrueer om polinome in die ring F[T] te faktoriseer. In hierdie tesis maak ons die konsep van Drinfeld modules bekend deur sekere aspekte daarvan te bestudeer. Ons gaan voort deur 'n voorbeeld te voorsien wat die analoog tussen Drinfeld modules en elliptiese kurwes illustreer. Uiteindelik, deur gebruik te maak van Drinfeld modules, bevestig ons hierdie analoog deur die algoritme vir die faktorisering van polinome oor eindige liggame te veskaf.
44

Minimal zero-dimensional extensions

Unknown Date (has links)
The structure of minimal zero-dimensional extension of rings with Noetherian spectrum in which zero is a primary ideal and with at most one prime ideal of height greater than one is determined. These rings include K[[X,T]] where K is a field and Dedenkind domains, but need not be Noetherian nor integrally closed. We show that for such a ring R there is a one-to-one correspondence between isomorphism classes of minimal zero-dimensional extensions of R and sets M, where the elements of M are ideals of R primary for distinct prime ideals of height greater than zero. A subsidiary result is the classification of minimal zero-dimensional extensions of general ZPI-rings. / by Marcela Chiorescu. / Thesis (Ph.D.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.
45

A class of rational surfaces with a non-rational singularity explicitly given by a single equation

Unknown Date (has links)
The family of algebraic surfaces X dened by the single equation zn = (y a1x) (y anx)(x 1) over an algebraically closed eld k of characteristic zero, where a1; : : : ; an 2 k are distinct, is studied. It is shown that this is a rational surface with a non-rational singularity at the origin. The ideal class group of the surface is computed. The terms of the Chase-Harrison-Rosenberg seven term exact sequence on the open complement of the ramication locus of X ! A2 are computed; the Brauer group is also studied in this unramied setting. The analysis is extended to the surface eX obtained by blowing up X at the origin. The interplay between properties of eX , determined in part by the exceptional curve E lying over the origin, and the properties of X is explored. In particular, the implications that these properties have on the Picard group of the surface X are studied. / by Drake Harmon. / Vita. / Thesis (Ph.D.)--Florida Atlantic University, 2013. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.
46

Unique decomposition of direct sums of ideals

Unknown Date (has links)
We say that a commutative ring R has the unique decomposition into ideals (UDI) property if, for any R-module which decomposes into a finite direct sum of indecomposable ideals, this decomposition is unique up to the order and isomorphism class of the ideals. In a 2001 paper, Goeters and Olberding characterize the UDI property for Noetherian integral domains. In Chapters 1-3 the UDI property for reduced Noetherian rings is characterized. In Chapter 4 it is shown that overrings of one-dimensional reduced commutative Noetherian rings with the UDI property have the UDI property, also. In Chapter 5 we show that the UDI property implies the Krull-Schmidt property for direct sums of torsion-free rank one modules for a reduced local commutative Noetherian one-dimensional ring R. / by Basak Ay. / Thesis (Ph.D.)--Florida Atlantic University, 2010. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2010. Mode of access: World Wide Web.
47

Ore localizations and irreducible representations of the first Weyl algebra.

Zhang, Ying-Lan. Muller, Bruno, J. Unknown Date (has links)
Thesis (Ph.D.)--McMaster University (Canada), 1990. / Source: Dissertation Abstracts International, Volume: 52-10, Section: B, page: 5315. Supervisor: Bruno J. Muller.
48

Discriminante da potÃncia de um nÃmero algÃbrico / On the discriminant of the power of an algebraic number

Joserlan Perote da Silva 28 July 2010 (has links)
FundaÃÃo de Amparo à Pesquisa do Estado do Cearà / Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Seja alfa um nÃmero algÃbrico que nÃo à raiz de um nÃmero racional. Mostraremos que o discriminante de alfa elevado a n tende a infinito com n tendendo a infinito e daremos um limite inferior para este discriminante em termos do grau de alfa, sua medida de Mahler e n. / Let alfa be an algebraic number which is not a root of a racional number. We show that the discriminant of alfa n tends to infinity with n tending to infinity and give a lower bound for this discriminant in terms of the degree of alfa, its Mahlerâs measure and n.
49

Grupos abelianos-por-nilpotentes do tipo homologico 'FP IND.3' / Abelian-by-nilpotent of homological type 'FP IND.3'

Rodrigues, Claudenir Freire 12 April 2006 (has links)
Orientador: Dessislava H. Kochloukova / Tese (doutorado) - Universidade Estadual de Campinas. Instituto de Matematica, Estatistica e Computação Cientifica / Made available in DSpace on 2018-08-07T18:15:42Z (GMT). No. of bitstreams: 1 Rodrigues_ClaudenirFreire_D.pdf: 1150293 bytes, checksum: 63045fd15f6ef421699cbcf26de55d92 (MD5) Previous issue date: 2006 / Resumo: Neste trabalho estudamos grupos abstratos finitamente gerados G que são extensões cindidas de um grupo abeliano A por um grupo Q nilpotente de classe 2. Mostramos que se G tem tipo homológico F P3, então o quociente G/N também tem tipo homológico F P3 onde N é o fecho normal do centro de Q em G. Observamos que não existe classificação quando G pode ter tipo FP3, nem classificação para tipo F P2 ou ser finitamente apresentável. Por causa disso nós trabalhamos com um quociente especifico de G. Ainda fica em aberto se cada quociente de G tem tipo FP3 quando G tem tipo FP3. Observamos que isso vale quando G é grupo metabeliano, nesse caso a teoria de Bieri-Strebel pode ser aplicada / Abstract: We study abstract finitely generated groups G that are split extensions from A abelian group by Q nilpotent group of class two. We show that if G has homological type FP3 then the quotient group GjN has homological type FP3 too, where N is the normal closure of the center of Q in G. Since there is no classification when G is of type FP3, nor when G is of type FP2 or finitely presented we work with one specific quotient. It is an open problem whether every quotient of G has type F P3. This holds if G is a metabelian group and in this case the Bieri-Strebel theory applies / Doutorado / Doutor em Matemática
50

Resolutions mod I, Golod pairs

Gokhale, Dhananjay R. 20 September 2005 (has links)
Let <i>R</i> be a commutative ring, <i>I</i> be an ideal in <i>R</i> and let <i>M</i> be a <i>R/ I</i> -module. In this thesis we construct a <i>R/ I</i> -projective resolution of <i>M</i> using given <i>R</i>-projective resolutions of <i>M</i> and <i>I</i>. As immediate consequences of our construction we give descriptions of the canonical maps Ext<sub>R/I</sub><i>(M,N)</i> -> Ext<sub>R</sub><i>(M,N)</i> and Tor<sup>R</sup><sub>N</sub><i>(M, N)</i> -> Tor<sup>R/I</sup><sub>n</sub><i>(M, N)</i> for a <i>R/I</i> module <i>N</i> and we give a new proof of a theorem of Gulliksen [6] which states that if <i>I</i> is generated by a regular sequence of length r then ∐∞<sub>n=o</sub> Tor<sup>R/I</sup><sub>n</sub> <i>(M, N)</i> is a graded module over the polynomial ring </i>R/ I</i> [X₁. .. X<sub>r</sub>] with deg X<sub>i</sub> = -2, 1 ≤ i ≤ r. If <i>I</i> is generated by a regular element and if the <i>R</i>-projective dimension of <i>M</i> is finite, we show that <i>M</i> has a <i>R/ I</i>-projective resolution which is eventually periodic of period two. This generalizes a result of Eisenbud [3]. In the case when <i>R</i> = (<i>R</i>, m) is a Noetherian local ring and <i>M</i> is a finitely generated <i>R/ I</i> -module, we discuss the minimality of the constructed resolution. If it is minimal we call (<i>M, I</i>) a Golod pair over <i>R</i>. We give a direct proof of a theorem of Levin [10] which states thdt if (<i>M,I</i>) is a Golod pair over <i>R</i> then (Ω<sup>n</sup><sub>R/I</sub>R/I(M),I) is a Golod pair over <i>R</i> where Ω<sup>n</sup><sub>R/I</sub>R/I(M) is the nth syzygy of the constructed <i>R/ I</i> -projective resolution of <i>M</i>. We show that the converse of the last theorem is not true and if (Ω¹<sub>R/I</sub>R/I(M),I) is a Golod pair over <i>R</i> then we give a necessary and sufficient condition for (<i>M, I</i>) to be a Golod pair over <i>R</i>. Finally we prove that if (<i>M, I</i>) is a Golod pair over <i>R</i> and if a ∈ <i>I</i> - m<i>I</i> is a regular element in </i>R</i> then (<i>M</i>, (a)) and (1/(a), (a)) are Golod pairs over <i>R</i> and (<i>M,I</i>/(a)) is a Golod pair over <i>R</i>/(a). As a corrolary of this result we show that if the natural map π : <i>R</i> → <i>R/1</i> is a Golod homomorphism ( this means (<i>R</i>/m, <i>I</i>) is a Golod pair over <i>R</i> ,Levin [8]), then the natural maps π₁ : <i>R</i> → <i>R</i>/(a) and π₂ : <i>R</i>/(a) → <i>R/1</i> are Golod homomorphisms. / Ph. D.

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