Recently, Costa [4] introduced the concept of n-coherent rings. In this note we shall give
some further properties of n-coherent rings. Let R be a ring and na nonnegative integer …

Relative coherence and preenvelopes Page 1 manuscripta math. 81, 243- 262 (1993)
manuscripta mathematica 9 Springer rlag 1993 RELATIVE COHERENCE AND …

A ring R is called left P-coherent in case each principal left ideal of R is finitely presented. A
left R-module M (resp. right R-module N) is called D-injective (resp. D-flat) if Ext1 (G, M)= 0 …

In this article, a new semistar operation, called the q-operation, on a commutative ring R is
introduced in terms of the ring Q 0 (R) of finite fractions. It is defined as the map q: F q (R)→ F …

Let R be a ring. Recall that a left R-module M is coherent if every finitely generated
submodule of M is finitely presented. R is a left coherent ring if the left R-module RR is …

Let R be a ring. A left R-module M is said to be min-injective if for any simple left ideal I. A
right R-module N is called min-flat if for any simple left ideal I. R is said to be a left min …

INTRODUCTION Let R be a ring and R-Mod the category of left R-modules. If F is a left
Gabriel topology on R, then there is an associated quotient category (R, F)-~ od which is the …

Let Rbe a ring with identity. Chase [5] has characterized the right coherent rings; he has
shown that arbitrary products of RR are flat if and only if finitely generated submodules of …

ABSTRACT A module M is called strongly FP-injective if Ext i (P, M)= 0 for any finitely
presented module P and all i≥ 1.(Pre) envelopes and (pre) covers by strongly FP-injective …

868 MARTINEZ HERNANDEZ where F'is a flat and F-divisible module, can be completed
commutatively. b) The diagram can be completed only by means of autornorphisms of F. In …