Abstract. The first part of the paper is concerned, among other things, with a characterization of filter regular sequences in terms of modules of generalized fractions. This characterization leads to a description, in terms of generalized fractions, of the structure of an arbitrary local cohomology module of a finitely generated module over a notherian ring. In the second part of the paper, we establish homomorphisms between the homology modules of a Koszul complex and the homology modules of a certain complex of modules of generalized fractions. Using these homomorphisms, we obtain a characterization of unconditioned strong ^-sequences.
§0. IntroductionThroughout this note A is a commutative ring (with non-zero identity), α is an ideal of A and M is an A-module.There is a lot of current interest in the theory of filter regular sequences and unconditioned strong d-sequences (u.s.d-sequences) in commutative algebra; and, in recent years, there have appeared many papers concerned with the role of these sequences in the theory of local cohomology. The main purpose of this note is to establish connections between modules of generalized fractions introduced in [7] and the above mentioned sequences. This paper is divided in two sections. In the first section we provide a characterization of α-filter regular sequences in terms of modules of generalized fractions. This result is a slight generalization of the Exactness Theorem [5, 3.1]. In [9], Sharp and the third author proved, in certain situation, for a finitely generated module N over a (Noetherian) local ring R having maximal ideal m, that the i-th local cohomology module H^(N) is isomorphic to the i-th homology module of a certain complex of modules of generalized fractions. Our characterization of α-filter regular sequences, in this paper, yields improved forms of the above theorem and the results