Projective modules

I Kaplansky - Annals of Mathematics, 1958 - JSTOR
… integral domain and M a torsion-free R-module which is a direct sum of modules of countable
rank, then any direct summand of M is likewise a direct sum of modules of countable rank. …

Simple-direct-projective modules

Y Ibrahim, MT Koşan, TC Quynh… - Communications in …, 2016 - Taylor & Francis
… if and only if the direct sum of any two simple-direct-projective modules is again simple-…
that the direct sum of simple-direct-projective modules need not be simple-direct-projective. …

Quasi-projective covers and direct sums

A Koehler - Proceedings of the American Mathematical Society, 1970 - ams.org
… Every finitely generated module is quasi-projective; … The direct sum of every pair of
quasiprojective … The direct sum of two quasi-projective modules is always quasi…

[PDF][PDF] Directing projective modules

D Happel, CM Ringel - Archiv der Mathematik, 1993 - core.ac.uk
… Since B is the support algebra of M, there exists some direct summand Mj of M with Hom (M;,
I) # O, thus we obtain Mj. =~ I ~ rB M~, impossible. This shows that M as a B-…

Properties of direct summands of modules

JL Garcia - Communications in Algebra, 1989 - Taylor & Francis
modules have the SSP and give an answer when the module is supposed to be a direct sum
… of whether a quasiprojective module has the SSP (or a quasi-injective module has the SIP) …

Direct sums of injective and projective modules

PAG Asensio, SK Jain, AK Srivastava - Journal of Algebra, 2010 - Elsevier
… v∈U Cv ), where the Cu are injective modules and Cv are projective modules. By Kaplansky
[9], we know that each projective module is a direct sum of countably generated modules. …

Pure-direct-projective modules

R Alizade, SE Toksoy - Journal of Algebra and Its Applications, 2024 - World Scientific
… that direct summands of pure-direct-projective right R-modules are pure-direct-projective (…
and the converse is true when the direct sum of two pure-direct-projective right R-modules

Big projective modules are free

H Bass - Illinois Journal of Mathematics, 1963 - projecteuclid.org
… of a countably infinite direct sum, P, of nonzero countably generated projective modules. We
must … But this is evident from the remark above since an infinite direct sum cannot be finitely …

On projective modules with the exchange property

K Yamagata - Science Reports of the Tokyo Kyoiku Daigaku, Section …, 1974 - JSTOR
… to study the direct sum of indecomposable projective modules which has … direct sums of
indecomposable projective modules and, particularly, the ring over which all projective modules

On essential extensions of direct sums of either injective or projective modules

MT Koşan, TC Quynh - Journal of Algebra and Its Applications, 2014 - World Scientific
sums of M-injective modules and projective modules in σ[M]. … via direct sums of injective
modules and projective modules. … of the direct sum of injective right R-modules is projective if …