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 …

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 …

We first prove that if a monomorphism is a phantom envelope of a left R-module, then its
cokernel is pure-projective; if R is a left coherent ring and an epimorphism is an Ext Ext …

In this paper, we introduce and study the notion of strongly $\phi $-$ w $-flat modules. The
$\phi $-$ w $-weak global dimension $\phi $-$ w $-w. gl. dim $(R) $ of an NP-ring $ R $ is …

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) …

In this paper, we first introduce and study the notions of strongly $\phi $-flat modules and
strongly nonnil-injective modules. And then, we investigate the homology dimensions of …

n-FLAT AND n-FP-INJECTIVE MODULES 1. Introduction We use R-Mod (resp., Mod-R) to
denote the category of all left (resp., right) Page 1 Czechoslovak Mathematical Journal, 61 (136) …

Let m and n be fixed positive integers and M a right R-module. Recall that M is said to be ($
m $, $ n $)-injective if $ Ext^ 1$(P, M)= 0 for any ($ m $, $ n $)-presented right R-module P; …

In this paper, we introduce and study the class of $\phi $-$ w $-flat modules which are
generalizations of both $\phi $-flat modules and $ w $-flat modules. The $\phi $-$ w $-weak …

In this paper, we introduce the notion of fpn-injective and fpn-flat modules, and investigate
their properties. In particular, we prove that every left R-module has an fpn-injective cover …