No description available.

The thesis is mainly concerned with properties of the concept "σ-purity" introduced by J. Lambek in "Torsion Theories, Additive Semantics and Rings of Quotients", (Springer-Verlag, 1971). In particular we are interested in modul es M for which every exact sequence of the form O→M→K→L→O (or O→K→M→L→O or O→K→L→M→O) is σ-pure exact. Modules of the first type turn out to be precisely the σ- injective modules of O. Goldman (J. Algebra 13, (1969), 10-47). This characterization allows us to study σ- injectivity from the perspective of purity. Similarly the demand that every short exact sequence of modules of the form O→K→M→L→O or O→K→L→M→O be σ-pure exact leads to concepts which generalize regularity and flatness respectively. The questions of which properties of regularity and flatness extend to these more general concepts of σ- regularity and σ-flatness are investigated. For various classes of rings R and torsion radicals σ on R-mod, certain conditions equivalent to the σ-regularity and the σ-injectivity of R are found. We also introduce some new dimensions and study semi-σ-flat and semi-σ-injective modules (defined by suitably restricting conditions on σ-flat and σ-injective modules). We further characterize those rings R for which every R-module is semi- σ-flat. The related concepts of a projective cover and a perfect ring (introduced by H. Bass in Trans. Amer. Math. Soc. 95, (1960), 466-488) are extended in a 'natural way and, inter alia , we obtain a generalization of a famous theorem of Bass. Lastly, we develop a relativized version of the Jacobson Radical which is shown to have properties analogous to both the classical Jacobson Radical and a radical due to J.S. Golan. / Thesis (Ph.D.)-University of Natal, 1992.

No description available.

Thesis(M.S.)--Auburn University, 2006. / Abstract. Vita. Includes bibliographic references (p.25).

Thesis (Ph. D.)--University of Washington, 1999. / Vita. Includes bibliographical references (p. 83-84).

Thesis (Ph. D.)--University of Chicago, Dept. of Mathematics, June 2000. / Includes bibliographical references. Also available on the Internet.

Thesis (Ph.D.)--Ohio University, June, 2005. / Title from PDF t.p. Includes bibliographical references (p. 65-69)

Thesis (Ph. D.)--Ohio State University, 2005. / Title from first page of PDF file. Document formatted into pages; contains viii, 87 p. Includes bibliographical references (p. 85-87). Available online via OhioLINK's ETD Center

This thesis is aimed at generalizing notions of rings to modules. In par-ticular, notions of completely prime ideals, s-prime ideals, 2-primal rings and nilpotency of elements of rings are respectively generalized to completely prime submodules and classical completely prime submodules, s-prime submodules, 2-primal modules and nilpotency of elements of modules. Properties and rad-icals that arise from each of these notions are studied.

In the first chapter we give an outline of classical KRULL rings as in SAMUEL (1964), BOURBAKI (1965) and FOSSUM (1973). In the second chapter we introduce two notions important to our treatment of KRULL theory. The first is injective modules and.the second torsion theories. We then look at injective modules over Noetherian rings as in MATLIS [1958] and then over KRULL rings as in BECK [1971]. We show that for a KRULL ring there is a torsion theory (N,M) where N is the pseudo-zero modules and M the set of N-torsion-free (BECK calls these co-divisorial) modules. From LAMBEK [1971] there is a full abelian sub category C, namely the category of N-torsion-free, N-divisible modules, with exact reflector. We show in C (I) every direct sum of injective modules is injective and (II) C has global dimension at most one. It is these two properties that we exploit in the third chapter to give another characterization of KRULL rings. Then we generalize this to rings with zero-divisors and find that (i) R has to be reduced (ii) the ring is KRULL if and only if it is a finite product of fields and KRULL domains (iii) the injective envelope of the ring is semi-simple artinian. We then generalize the ideas to rings of higher dimension.