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1.
Davide Penazzi 《Archive for Mathematical Logic》2011,50(7-8):743-758
We initiate a geometric stability study of groups of the form G/G 00, where G is a 1-dimensional definably compact, definably connected, definable group in a real closed field M. We consider an enriched structure M?? with a predicate for G 00 and check 1-basedness or non-1-basedness for G/G 00, where G is an additive truncation of M, a multiplicative truncation of M, SO 2(M) or one of its truncations; such groups G/G 00 are now interpretable in M??. We prove that the only 1-based groups are those where G is a sufficiently ??big?? multiplicative truncation, and we relate the results obtained to valuation theory. In the last section we extend our results to ind-hyperdefinable groups constructed from those above. 相似文献
2.
Let G be an almost simple algebraic group defined over Fp forsome prime p. Denote by G1 the first Frobenius kernel in G andlet T be a maximal torus. In this paper we study certain Jantzentype filtrations on various modules in the representation theoryof G1T. We have such filtrations on the baby Verma modules Z,where is a character of T. They are obtained via a certaindeformation of the natural homomorphism from Z into its contravariantdual Z. Using the same deformation we construct for each projectiveG1T-module Q a filtration of the vector space . We then prove that this filtration may also bedescribed in terms of the above-mentioned homomorphism Z() Z() and this leads us to a sum formula for our filtrations.When Q is indecomposable with highest weight in the bottom alcove(with respect to some special point) we are able to computethe filtrations on F(Q) explicitly for all . This is then thestarting point of an induction which proceeds via wall crossingsto higher alcoves. If our filtrations behave as expected undersuch wall crossings then we obtain a precise relation betweenthedimensions of the layers in the filtrations of F(Q) for an arbitraryindecomposable projective Q and the coefficients in the correspondingKazhdanLusztig polynomials. We conclude the paper byproving that the above results in the G1T theory have some analoguesin the representation theory of G (where, however, we have towork with representations of bounded highest weights) and thecorresponding theory for quantum groups at roots of unity. Theseresults extend previous work by the first author. 2000 MathematicsSubject Classification: 20G05, 20G10, 17B37. 相似文献
3.
In this article, we describe all group gradings by a finite abelian group Γ of a simple Lie algebra of type G 2 over an algebraically closed field F of characteristic zero. 相似文献
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6.
Mong-Lung Lang 《代数通讯》2013,41(8):3691-3702
We determine the signatures of the congruence subgroups of the Hecke groups G 4 and G 6. 相似文献
7.
G. Criscuolo. 《Mathematics of Computation》2004,73(245):243-250
Recently, Mastroianni and Monegato derived error estimates for a numerical approach to evaluate the integral
where or or and is a smooth function (see G. Mastroianni and G. Monegato, Error estimates in the numerical evaluation of some BEM singular integrals, Math. Comp. 70 2001, 251-267). The error bounds for the quadrature rule approximating the inner integral given in Theorems 3, 4 of that paper are not correct according to the proof. However, following a different approach, we are able to improve the pointwise error estimates given in that paper.
where or or and is a smooth function (see G. Mastroianni and G. Monegato, Error estimates in the numerical evaluation of some BEM singular integrals, Math. Comp. 70 2001, 251-267). The error bounds for the quadrature rule approximating the inner integral given in Theorems 3, 4 of that paper are not correct according to the proof. However, following a different approach, we are able to improve the pointwise error estimates given in that paper.
8.
Let G be a compact Lie group and let U(G) denote the Euler ring of G constructed by tom Dieck [5, 6]. The main result of the paper (Theorem 4.1) describes the homomorphism
induced by the inclusion
.
Dedicated to Professor Vladimir Arnold 相似文献
9.
Jagerman David L. Balcıoglu Barış Altıok Tayfur Melamed Benjamin 《Queueing Systems》2004,46(3-4):481-506
It is known that correlations in an arrival stream offered to a single-server queue profoundly affect mean waiting times as compared to a corresponding renewal stream offered to the same server. Nonetheless, this paper uses appropriately constructed GI/G/1 models to create viable approximations for queues with correlated arrivals. The constructed renewal arrival process, called PMRS (Peakedness Matched Renewal Stream), preserves the peakedness of the original stream and its arrival rate; furthermore, the squared coefficient of variation of the constructed PMRS equals the index of dispersion of the original stream. Accordingly, the GI/G/1 approximation is termed PMRQ (Peakedness Matched Renewal Queue). To test the efficacy of the PMRQ approximation, we employed a simple variant of the TES+ process as the autocorrelated arrival stream, and simulated the corresponding TES +/G/1 queue for several service distributions and traffic intensities. Extensive experimentation showed that the proposed PMRQ approximations produced mean waiting times that compared favorably with simulation results of the original systems. Markov-modulated Poisson process (MMPP) is also discussed as a special case. 相似文献
10.
In this note, we consider the steady-state probability of delay (PW) in the C2/G/1 queue and the steady-state probability of loss (ploss) in the C2/G/1 loss system, in both of which the interarrival time has a two-phase Coxian distribution. We show that, for cX
2<1, where cX is the coefficient of variation of the interarrival time, both ploss and PW are increasing in β(s), the Laplace–Stieltjes transform of the general service-time distribution. This generalises
earlier results for the GE2/G/1 queue and the GE2/G/1 loss system. The practical significance of this is that, for cX
2<1, ploss in the C2/G/1 loss system and PW in the C2/G/1 queue are both increasing in the variability of the service time.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
11.
Yao David D. W. Chaudhry M. L. Templeton J. G. C. 《The Journal of the Operational Research Society》1987,38(1):109-109
Journal of the Operational Research Society - 相似文献
12.
An edge of a k-connected graph is said to be k-contractible if the contraction of the edge results in a k-connected graph. A k-connected graph with no k-contractible edge is called contraction critically k-connected. For k≥4, we prove that if both G and its complement Gˉ are contraction critically k-connected, then |V(G)|<k
5/3+4k
3/2.
Received: October, 2001 Final version received: September 18, 2002
AMS Classification: 05C40 相似文献
13.
Silke W.W. Rolles 《Probability Theory and Related Fields》2006,135(2):216-264
Let G be a finite tree. It is shown that edge-reinforced random walk on ℤ×G with large initial weights is recurrent. This includes recurrence on multi-level ladders of arbitrary width. For edge-reinforced
random walk on {0,1, . . . ,n}×G, it is proved that asymptotically, with high probability, the normalized edge local times decay exponentially in the distance
from the starting level. The estimates are uniform in n. They are used in the recurrence proof. 相似文献
14.
非连通图G1∪G2及G1∪G2∪K2的优美性 总被引:6,自引:0,他引:6
将k-优美图的概念进行了推广,引入了k-l优美图及标号间距的概念,并以此为基础,分别推出了一般情形下判定非连通图G1∪G2及G1∪G2∪K2是优美图的两个充分条件;同时得出了图(C3VK^-n)∪st(m)∪K2是优美图,其中k、l为自然数,l〈k,C3是长为3的圈,Kn为n个顶点的完全图,K^-n是Kn的补图,St(m)表示m+1个顶点的星形树,C3VK^-n是C3与K^-n的联图. 相似文献
15.
Edward S. Letzter 《代数通讯》2013,41(4):1889-1893
16.
We classify seven-dimensional nilpotent Lie groups, decomposable or of nilpotency step at most 4, endowed with left-invariant purely coclosed G2-structures. This is done by going through the list of all seven-dimensional nilpotent Lie algebras given by Gong, providing an example of a left-invariant 3-form φ which is a pure coclosed G2-structure (i.e., it satisfies , ) for those nilpotent Lie algebras that admit them; and by showing the impossibility of having a purely coclosed G2-structure for the rest of them. 相似文献
17.
M. Filali 《Semigroup Forum》1994,48(1):163-168
LetG be a discrete abelian group,Ĝ the character group ofG, andl
∞(G)* the conjugate ofl
∞(G) equipped with an Arens product. In many cases, we can find unitary functionsf such that χf is almost convergent to zero for all χ∈Ĝ. Some of these functions are then used to produce elements μ∈l
∞(G)* such that γμ=0 whenever γ is an annihilator ofC
0(G). Regarded as Borel measures on βG, these elements satisfyxμ=0 for allx∈βG/G. They belong to the radical ofl
∞(G)*, and each of them generates a left ideal ofl
∞(G)* that contains no minimal left ideal. 相似文献
18.
We consider an extension of Gödel logic by a unary operator that enables the addition of non-negative reals to truth-values. Although its propositional fragment has a simple proof system, first-order validity is Π 2-hard. We explain the close connection to Scarpellini’s result on Π 2-hardness of ?ukasiewicz’s logic. 相似文献
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Demetres D. Kouvatsos 《The Journal of the Operational Research Society》1988,39(2):183-200
The principle of maximum entropy is used to analyse a G/G/1 queue at equilibrium when the constraints involve only the first two moments of the interarrival-time and service-time distributions. Robust recursive relations for the queue-length distribution are determined, and a probability density function analogue is characterized. Furthermore, connections with classical queueing theory and operational analysis are established, and an overall approximation, based on the concept of ‘global’ maximum entropy, is introduced. Numerical examples provide useful information on how critically system behaviour is affected by the distributional form of the interarrival and service times, and favourable comparisons are made with diffusion and other approximations. Comments on the implication of the work to the analysis of more general queueing systems are included. 相似文献