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71.
Stuart A. Steinberg 《Czechoslovak Mathematical Journal》2001,51(2):387-394
In an -group M with an appropriate operator set it is shown that the -value set (M) can be embedded in the value set (M). This embedding is an isomorphism if and only if each convex -subgroup is an -subgroup. If (M) has a.c.c. and M is either representable or finitely valued, then the two value sets are identical. More generally, these results hold for two related operator sets 1 and 2 and the corresponding -value sets
and
. If R is a unital -ring, then each unital -module over R is an f-module and has
exactly when R is an f-ring in which 1 is a strong order unit. 相似文献
72.
Extensions of crossed modules in Lie algebras with abelian kernel are studied, particularly backward and forward induced extensions and related properties. The set Opext((U, Q, ), (R, K, )) of congruence classes of extensions of (R, K, ) by (U, Q, ) is endowed with a K-vector space structure. This K-vector space appears in a five-term natural and exact sequence associated with an extension of crossed modules.2000 Mathematics Subject Classification: 17B56, 17B99, 18G99 相似文献
73.
Ralf Kemper 《Proceedings of the American Mathematical Society》2000,128(3):709-712
It is an open question as to whether every left coherent ring satisfying the intersection property for finitely generated left ideals of is a right-product-trace-ring or not. is a right-product-trace-ring iff every product of trace-right--modules (= universally torsionless-right--modules) is a trace-right--module. This question is shown to have a negative answer. Furthermore, looking at all valuation domains, the complete product-trace-rings, the product-trace-rings and the product-content-rings are characterized.
74.
We investigate certain finite subgroups of , where is a finite nilpotent group. Such a group gives rise to a -module; we study the characters of these modules to limit the structure of . We also exhibit some exotic subgroups .
75.
利用自行研制的空心微球耐外压装置和充气装置,测试了目前激光惯性约束聚变实验打靶使用的空心玻璃微球耐内压能力和耐外压能力。空心玻璃微球采用液滴法制备,直径为180~250 mm、壁厚为0.8~4.0 mm。理论计算表明,当微球纵横比超过90时,耐外压能力与球壳材料的杨氏模量有关,由此测量得到的空心玻璃微球杨氏模量为55~75 GPa。玻璃微球的耐内压能力主要与球壳材料的抗拉强度有关,实验测量得到的玻璃微球抗拉强度为90~140 MPa。 相似文献
76.
Semra Doğruöz 《Czechoslovak Mathematical Journal》2008,58(2):381-393
An R-module M is said to be an extending module if every closed submodule of M is a direct summand. In this paper we introduce and investigate the concept of a type 2 τ-extending module, where τ is a hereditary torsion theory on Mod-R. An R-module M is called type 2 τ-extending if every type 2 τ-closed submodule of M is a direct summand of M. If τ
I
is the torsion theory on Mod-R corresponding to an idempotent ideal I of R and M is a type 2 τ
I
-extending R-module, then the question of whether or not M/MI is an extending R/I-module is investigated. In particular, for the Goldie torsion theory τ
G
we give an example of a module that is type 2 τ
G
-extending but not extending. 相似文献
77.
JavaStatSoft, implemented using Java, is an open-source software for performing statistics. The current features of JavaStatSoft
are described. Several well-known patterns the software used are introduced. In addition, based on these patterns and the
experience in developing the software, a new framework, referred to as Data Analysis Module, is proposed to help programmers
develop a user-friendly software for data analysis. 相似文献
78.
Using actions of free monoids and free associative algebras, we establish some Schreier-type formulas involving ranks of actions and ranks of subactions in free actions or Grassmann-type relations for the ranks of intersections of subactions of free actions. The coset action of the free group is used to establish a generalization of the Schreier formula in the case of subgroups of infinite index. We also study and apply large modules over free associative and free group algebras. 相似文献
79.
We introduce the notion of n-fold track extensions of a category C by a natural system D and prove that such extensions represent classes in the cohomology of C with coefficients in D introduced by Baues–Wirsching. This generalizes a result of Huebschmann on the cohomology of groups. 相似文献
80.