Precovers and preenvelopes by phantom and Ext-phantom morphisms

L Mao - Communications in Algebra, 2016 - Taylor & Francis
A morphism f: M→ N of left R-modules is called a phantom morphism if the induced
morphism for every (finitely presented) right R-module A. Similarly, a morphism g: M→ N of …

Higher phantom and Ext-phantom morphisms

L Mao - Journal of Algebra and Its Applications, 2018 - World Scientific
A morphism f: M→ N of left R-modules is called an n-phantom morphism if the induced
morphism Tor n R (A, f)= 0 for every (finitely presented) right R-module A. Analogously, a …

Higher phantom morphisms with respect to a subfunctor of Ext

L Mao - Algebras and Representation Theory, 2019 - Springer
A morphism f: M→ N f:M→N of left R-modules is called an n-phantom morphism (resp. a Tor
n-epimorphism) if the induced morphism Tor n (A, f)= 0 (resp. Tor n (A, f) is an epimorphism) …

On n-phantom and n-Ext-phantom Morphisms

K Lan, B Lu - Taiwanese Journal of Mathematics, 2021 - JSTOR
This paper extends many conclusions based on phantom envelopes and Ext-phantom
covers of modules, and we find that many important properties still hold after replacing …

Remarks on fp-Injective and fp-Flat Modules

L Mao - Arabian Journal for Science and Engineering, 2011 - Springer
Abstract A left R-module M is said to be fp-injective if, for every monomorphism K→ L with K
and L finitely presented left R-modules, Hom (L, M)→ Hom (K, M) is an epimorphism. A right …

Neat-phantom and clean-cophantom morphisms

L Mao - Journal of Algebra and Its Applications, 2021 - World Scientific
Let ℱ 𝒫∞ R be the class of all left R-modules M which has a projective resolution by finitely
generated projectives. An exact sequence 0→ A→ B→ C→ 0 of right R-modules is called …

Modules which are invariant under nilpotents of their envelopes and covers

TC Quynh, A Abyzov, DD Tai - Journal of Algebra and Its …, 2021 - World Scientific
A module is called nilpotent-invariant if it is invariant under any nilpotent endomorphism of
its injective envelope [MT Koşan and TC Quynh, Nilpotent-invaraint modules and rings …

Projectivity relative to closed (neat) submodules

Y Durğun - Journal of Algebra and Its Applications, 2022 - World Scientific
An R-module F is called closed (neat) projective if, for every closed (neat) submodule L of
every R-module M, every homomorphism from F to M/L lifts to M. In this paper, we study …

Relatively free modules on ring extensions

S Guo, X Wang, Z Yi - Communications in Algebra, 2021 - Taylor & Francis
A ring extension is a ring homomorphism preserving identities. In this paper, we give the
definition of relatively free modules on ring extensions and develop some basic properties of …

Endomorphism rings and the category of finitely generated projective modules

JL Garcia, M Hernández… - Communications in …, 2000 - Taylor & Francis
Endomorphism rings and the category of finitely generated projective modules Page 1
COMMLTNICATIONS IN ALGEBRA, 28(8), 3837-3 852 (2000) Endomorphism rings and the …