In this paper, some results on vanishing and non-vanishing of generalized local cohomology modules are presented and some relations between those modules and, Ext and ordinary local cohomology modules are studied. Also, several cofiniteness propositions for generalized local cohomology modules are established which, among other things, provide an alternative answer to a question in [Y2].
Let $R$ be a commutative Noetherian ring with identity, $I$ be an ideal of $R$ and $M$ be an $R$-module such that $Ext^j_R(R/I, M)$ is finitely generated for all $j$. We prove that if $\dim H^i_I(M)\leq 1$ for all $i$, then for any $i \geq 0$ and for any submodule $N$ of $H^i_I(M
Suppose that $\ab$ is an ideal of a given commutative Noetherian ring $R$ such that the $R$-modules $H^1_{\ab}(M)$ and $H^3_{\ab}(M)$ are $\ab$-cofinite, for every finitely generated $R$-modules $M$. In this paper, it is shown that the $R$-modules $H^i_{\ab}(M)$ are $\ab$-cofinit
let $r$ be a commutative noetherian ring with non-zero identity and $fa$ an ideal of $r$. let $m$ be a finite $r$--module of finite projective dimension and $n$ an arbitrary finite $r$--module. we characterize the membership of the generalized local cohomology modules $lc^{i}_{fa
Let $R$ be a commutative Noetherian ring with non-zero identity and $a$ an ideal of $R$. Let $M$ be a finite $R$--moduleof finite projective dimension and $N$ an arbitrary finite $R$--module. We characterize the membership of the generalized local cohomology modules $H^{i}_{a}(M,