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951.
《代数通讯》2013,41(9):4291-4299
Abstract Marciniak and Sehgal (Marciniak, Z., Sehgal, S. K. (1997). Constructing free subgroups of integral group rings units. Proc. Amer. Math. Soc.125(4):1005–1009) constructed free subgroups in U(?[G]) whenever Ghas a non normal finite subgroup. In this paper we construct free subgroups in U(?[G]), where Gis a group whose subgroups are all normal. 相似文献
952.
C. Bekh-Ochir 《代数通讯》2013,41(8):2697-2706
We describe the T-ideal of identities and the T-space of central polynomials for the unitary finite dimensional Grassmann algebra over a finite field. 相似文献
953.
A. Vasiu 《Mathematische Nachrichten》2010,283(8):1068-1113
Let k be an algebraically closed field of positive characteristic p. We first classify the D ‐truncations mod p of Shimura F ‐crystals over k and then we study stratifications defined by inner isomorphism classes of these D ‐truncations. This generalizes previous works of Kraft, Ekedahl, Oort, Moonen, and Wedhorn. As a main tool we introduce and study Bruhat F ‐decompositions; they generalize the combined form of Steinberg theorem and of classical Bruhat decompositions for reductive groups over k (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
954.
In Bautista-Ancona and Diaz-Vargas (2006) [B-D] a characterization and complete listing is given of the imaginary quadratic extensions K of k(x), where k is a finite field, in which the ideal class group has exponent two and the infinite prime of k(x) ramifies. The objective of this work is to give a characterization and list of these kind of extensions but now considering the case in which the infinite prime of k(x) is inert in K. Thus, we get all the imaginary quadratic extensions of k(x), in which the ideal class group has exponent two. 相似文献
955.
Resolution of computational aeroacoustics problems on unstructured grids with a higher-order finite volume scheme 总被引:1,自引:0,他引:1
X. Nogueira I. Colominas L. Cueto-Felgueroso F. Navarrina 《Journal of Computational and Applied Mathematics》2010,234(7):2089-2097
Computational fluid dynamics (CFD) has become increasingly used in the industry for the simulation of flows. Nevertheless, the complex configurations of real engineering problems make the application of very accurate methods that only work on structured grids difficult. From this point of view, the development of higher-order methods for unstructured grids is desirable. The finite volume method can be used with unstructured grids, but unfortunately it is difficult to achieve an order of accuracy higher than two, and the common approach is a simple extension of the one-dimensional case. The increase of the order of accuracy in finite volume methods on general unstructured grids has been limited due to the difficulty in the evaluation of field derivatives. This problem is overcome with the application of the Moving Least Squares (MLS) technique on a finite volume framework. In this work we present the application of this method (FV-MLS) to the solution of aeroacoustic problems. 相似文献
956.
V. P. Burichenko 《Algebra and Logic》2008,47(6):384-394
Let G = SL(n, q), where q is odd, V be a natural module over G, and L = S2(V) be its symmetric square. We construct a 2-cohomology group H2(G, L). The group is one-dimensional over F
q if n = 2 and q ≠ 3, and also if (n, q) = (4, 3). In all other cases H2(G, L) = 0. Previously, such groups H2(G, L) were known for the cases where n = 2 or q = p is prime. We state that H2(G, L) are trivial for n ⩾ 3 and q = pm, m ⩾ 2. In proofs, use is made of rather elementary (noncohomological) methods.
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Translated from Algebra i Logika, Vol. 47, No. 6, pp. 687–704, November–December, 2008. 相似文献
957.
Ján Jakubík 《Czechoslovak Mathematical Journal》2008,58(1):183-202
In the present paper we deal with generalized MV-algebras (GMV-algebras, in short) in the sense of Galatos and Tsinakis. According to a result of the mentioned authors, GMV-algebras can be obtained by a truncation construction from lattice ordered groups. We investigate direct summands and retract
mappings of GMV-algebras. The relations between GMV-algebras and lattice ordered groups are essential for this investigation.
Supported by VEGA Agency grant 1/2002/05.
This work has been partially supported by the Slovak Academy of Sciences via the project Center of Excellence-Physics of Information,
grant I/2/2005. 相似文献
958.
R. M. Garipov 《Algebra and Logic》2008,47(1):18-31
On a crystallographic group, a condition of being topologically discrete is imposed which is weaker than is the conventional
requirement for an action on space to be discontinuous. Isomorphism classification is given for crystallographic groups in
three crystallographic classes in a 4-dimensional Minkowski space, which are defined by unimodular subgroups of the general
Lorentz group. In these classes are, respectively, 24, 36, and 68 crystallographic groups.
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Translated from Algebra i Logika, Vol. 47, No. 1, pp. 31–53, January–February, 2008. 相似文献
959.
K. V. Kostousov 《Algebra and Logic》2008,47(2):118-124
We point out a countable set of pairwise nonisomorphic Cayley graphs of the group ℤ4 that are limit for finite minimal vertex-primitive graphs admitting a vertex-primitive automorphism group containing a regular
Abelian normal subgroup.
Supported by RFBR grant No. 06-01-00378.
__________
Translated from Algebra i Logika, Vol. 47, No. 2, pp. 203–214, March–April, 2008. 相似文献
960.