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161.
Given a singular self-adjoint differential operator of order 2n with real coefficients we constructtwo sequences of regular self-adjoint differential expressionsr which converge to ina generalized sense of resolvent convergence. The first constructionis suitable when no information about the real resolvent setof is available. The second is suitablewhen we know a real point of the resolvent set of .The main application of this construction is in numerical solutionof singular differential equations. 相似文献
162.
I. Moerdijk 《K-Theory》2003,28(3):207-258
We observe that any regular Lie groupoid G over a manifold M fits into an extension K G E of a foliation groupoid E by a bundle of connected Lie groups K. If F is the foliation on M given by the orbits of E and T is a complete transversal to F , this extension restricts to T, as an extension K
T
G
T
E
T
of an étale groupoid E
T
by a bundle of connected groups K
T
. We break up the classification problem for regular Lie groupoids into two parts. On the one hand, we classify the latter extensions of étale groupoids by (non-Abelian) cohomology classes in a new ech cohomology of étale groupoids. On the other hand, given K and E and an extension K
T
G
T
E
T
over T, we present a cohomological obstruction to the problem of whether this is the restriction of an extension K G E over M; if this obstruction vanishes, all extensions K G E over M which restrict to a given extension over the transversal together form a principal bundle over a group of bitorsors under K. 相似文献
163.
In the context of the weak solutions of the Navier-Stokes equations we study the regularity of the pressure and its derivatives in the space-time neighbourhood of regular points. We present some global and local conditions under which the regularity is further improved. 相似文献
164.
An upper bound on the Ramsey number r(K2,n‐s,K2,n) where s ≥ 2 is presented. Considering certain r(K2,n‐s,K2,n)‐colorings obtained from strongly regular graphs, we additionally prove that this bound matches the exact value of r(K2,n‐s,K2,n) in infinitely many cases if holds. Moreover, the asymptotic behavior of r(K2,m,K2,n) is studied for n being sufficiently large depending on m. We conclude with a table of all known Ramsey numbers r(K2,m,K2,n) where m,n ≤ 10. © 2003 Wiley Periodicals, Inc. J Graph Theory 43: 252–268, 2003 相似文献
165.
We prove large deviation results on the partial and random sums Sn = ∑i=1n Xi,n≥1; S(t) = ∑i=1N(t) Xi, t≥0, where {N(t);t≥0} are non-negative integer-valued random variables and {Xn;n≥1} are independent non-negative random variables with distribution, Fn, of Xn, independent of {N(t); t≥0}. Special attention is paid to the distribution of dominated variation. 相似文献
166.
1. IntroductionLet f: Re -- R be a differelltiable fUnction. f reaChes its extremes on the setJ = {x E R"lfx(x) = 0}, (1.1)where,x(X) = (V,..., V)". (1.2)If jx can be observed exactly at any x e R", then there are various numerical methods toconstruct {xh}, xk E Re such that the distance d(xk, J) between uk and J tends to zero ask -- co. However, in many application problems jx can only be observed with noise, i.e.,the observation at time k 1 isYk 1 = fi(~k) (k 1, (1'3)where xk is … 相似文献
167.
In this paper k-sets of type (a, b) with respect to hyperplanes are constructed in finite projective spaces using powers of Singer cycles. These are then used to construct further examples of sets of type (a, b) using various disjoint sets. The parameters of the associated strongly regular graphs are also calculated. The construction technique is then related to work of Foulser and Kallaher classifying rank three subgroups of AL(1, p
R). It is shown that the sets of type (a, b) arising from the Foulser and Kallaher construction in the case of projective spaces are isomorphic to some of those constructed in the present paper. 相似文献
168.
Suppose that { f(n), n N
0
} is a sequence of positive real numbers and suppose that the sequence { a(n), n N
0
} is given by a(0) = 0, and, for n 1, by the convolution equation nf(n) = a* f(n). The resulting sequence is denoted by a(n) =
f
(n) and is called the De Pril transform of { f(n), n N
0
} . In this paper, we consider first- and second-order asymptotic behavior of {
f
(n), n N
0
} for a large class of subexponential sequences { f(n), n N
0
} . We also discuss some applications. 相似文献
169.
Baha-Eldin Khaledi Subhash Kochar 《Annals of the Institute of Statistical Mathematics》2001,53(3):620-630
Consider a multivariate mixture model where the random variables X
1, ..., X
n
given (1, ...,
n
), are conditionally independent. Conditions are obtained under which different kinds of positive dependence hold among X
i
's. The results obtained are applied to a variety of problems including the concomitants of order statistics and of record values; and to frailty models. 相似文献
170.
Richard Greiner Oliver Roth 《Proceedings of the American Mathematical Society》2001,129(12):3657-3664
We consider the linear functional for on the set of normalized univalent functions in the unit disk and use the result to disprove a conjecture of Bombieri.