(n, d)-Injective covers, n-coherent rings, and (n, d)-rings
W Li, B Ouyang - Czechoslovak Mathematical Journal, 2014 - Springer
It is known that a ring R is left Noetherian if and only if every left R-module has an injective
(pre) cover. We show that (1) if R is a right n-coherent ring, then every right R-module has an …
(pre) cover. We show that (1) if R is a right n-coherent ring, then every right R-module has an …
[PDF][PDF] On presented dimensions of modules and rings
D Zhou, Z Gong - International Journal of Mathematics …, 2010 - pdfs.semanticscholar.org
We define the presented dimensions for modules and rings to measure how far away a
module is from having an infinite finite presentation and develop ways to compute the …
module is from having an infinite finite presentation and develop ways to compute the …
Envelopes of commutative rings
Given a significative class ℱ of commutative rings, we study the precise conditions under
which a commutative ring R has an ℱ-envelope. A full answer is obtained when ℱ is the …
which a commutative ring R has an ℱ-envelope. A full answer is obtained when ℱ is the …
Precovers and preenvelopes under change of rings
L Mao - The Rocky Mountain Journal of Mathematics, 2015 - JSTOR
PRECOVERS AND PREENVELOPES UNDER CHANGE OF RINGS 1. Introduction. (Pre)covers
and (pre)envelopes were introduced in the early 19 Page 1 ROCKY MOUNTAIN JOURNAL …
and (pre)envelopes were introduced in the early 19 Page 1 ROCKY MOUNTAIN JOURNAL …
When Are Covers Relative to Two Classes Isomorphic
D Zhou - Communications in Algebra, 2010 - Taylor & Francis
Let ℒ1⊇ ℒ2 be classes of right R-modules, we introduce ℒ1-covering modules and
projective modules relative to ℒ2 to characterize the relations between the existences of ℒ1 …
projective modules relative to ℒ2 to characterize the relations between the existences of ℒ1 …