منابع مشابه
Extension functors of local cohomology modules
Let $R$ be a commutative Noetherian ring with non-zero identity, $fa$ an ideal of $R$, and $X$ an $R$--module. Here, for fixed integers $s, t$ and a finite $fa$--torsion $R$--module $N$, we first study the membership of $Ext^{s+t}_{R}(N, X)$ and $Ext^{s}_{R}(N, H^{t}_{fa}(X))$ in the Serre subcategories of the category of $R$--modules. Then, we present some conditions which ensure the exi...
متن کاملExtension between functors from groups
Motivated in part by the study of the stable homology of automorphism groups of free groups, we consider cohomological calculations in the category F(gr) of functors from finitely generated free groups to abelian groups. In particular, we compute the groups Ext F(gr) (T ◦a, T◦a) where a is the abelianization functor and T is the n-th tensor power functor for abelian groups. These groups are sho...
متن کاملOn Weakly Confluent Monadic String-Rewriting Systems
Madlener, K., P. Narendran, F. Otto and L. Zhang, On weakly confluent monadic string-rewriting systems, Theoretical Computer Science 113 (1993) 119-165. It is investigated as to how far the various decidability results for finite, monadic, and confluent string-rewriting systems can be carried over to the class of finite monadic string-rewriting systems that are only weakly confluent. Here a mon...
متن کاملSubalgebras of a Finite Monadic Boolean Algebra
For a finite n-element set X, n ≥ 1, let N [X] denote the number of elements of X and let p(n) denote the number of all partitions of X. If Bn is a Boolean algebra with n atoms, let A(Bn) be the set of all atoms of Bn. It is known that there exists a bijective correspondence between the set S(Bn) of all subalgebras of Bn and the set of all partitions of A(Bn), i.e., N [S(Bn)] = p(n). The follow...
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ژورنال
عنوان ژورنال: Fundamenta Mathematicae
سال: 1980
ISSN: 0016-2736,1730-6329
DOI: 10.4064/fm-110-2-75-90