共查询到20条相似文献,搜索用时 31 毫秒
1.
D. I. Panyushev 《Functional Analysis and Its Applications》2004,38(1):38-44
Let
be a reductive Lie algebra over an algebraically closed field of characteristic zero and
an arbitrary
-grading. We consider the variety
, which is called the commuting variety associated with the
-grading. Earlier it was proved by the author that
is irreducible, if the
-grading is of maximal rank. Now we show that
is irreducible for
and (E6,F4). In the case of symmetric pairs of rank one, we show that the number of irreducible components of
is equal to that of nonzero non--regular nilpotent G
0-orbits in
. We also discuss a general problem of the irreducibility of commuting varieties. 相似文献
2.
In this paper, Ore extensions in the class of Hopf algebras are studied. The classification theorem enables one to describe the Hopf--Ore extensions for the group algebras, for the algebras
and
, and for the quantum ax + b group. 相似文献
3.
Andrzej Nowik 《Czechoslovak Mathematical Journal》2000,50(4):865-877
We prove the following theorems:1. There exists an -covering with the property s
0.2. Under cov
there exists X such that
is not an -covering orX \ B is not an -covering].3. Also we characterize the property of being an -covering. 相似文献
4.
The N-heap Wythoffs game is a two-player impartial game with
N piles of tokens of sizes
Players take turns removing any number of tokens from a single pile, or removing
(a1,..., aN)
from all piles - ai tokens from the i-th pile,
providing that
where is the nim addition. The first player that cannot make a move loses. Denote all the
P-positions (i.e., losing positions) by
Two conjectures were proposed on the game by Fraenkel [7]. When
are fixed, i) there exists an integer N1
such that when
. ii) there exist integers N2
and _2 such that when
, the golden section.In this paper, we provide a sufficient condition for the conjectures to hold, and subsequently
prove them for the three-heap Wythoffs game with the first piles having up to 10 tokens.AMS Subject Classification: 91A46, 68R05. 相似文献
5.
Adhemar Bultheel Pablo González-Vera Erik Hendriksen Olav Njåstad 《Acta Appl Math》2000,61(1-3):101-118
From the Erds–Turán theorem, it is known that if f is a continuous function on
and L
n
(f, z) denotes the unique Laurent polynomial interpolating f at the (2 n + 1)th roots of unity, then
Several years later, Walsh and Sharma produced similar result but taking into consideration a function analytic in
and continuous on
and making use of algebraic interpolating polynomials in the roots of unity.In this paper, the above results will be generalized in two directions. On the one hand, more general rational functions than polynomials or Laurent polynomials will be used as interpolants and, on the other hand, the interpolation points will be zeros of certain para-orthogonal functions with respect to a given measure on
. 相似文献
6.
A class
of measurable functions on a probability space is called a Glivenko-Cantelli class if the empirical measuresP
n
converge to the trueP uniformly over
almost surely.
is a universal Glivenko-Cantelli class if it is a Glivenko-Cantelli Cantelli class for all lawsP on a measurable space, and a uniform Glivenko-Cantelli class if the convergence is also uniform inP. We give general sufficient conditions for the Glivenko-Cantelli and universal Glivenko-Cantelli properties and examples to show that some stronger conditions are not necessary. The uniform Glivenko-Cantelli property is characterized, under measurability assumptions, by an entropy condition. 相似文献
7.
V. G. Safonov 《Algebra and Logic》2003,42(6):407-412
It is proved that all proper totally local subformations of a non one-generated totally local formation
of finite groups are one-generated iff
coincides with a formation
of all soluble -groups, where ||=2. 相似文献
8.
For a cardinal , we say that a subset B of a space X is C
-compact in X if for every continuous function
is a compact subset of
. If B is a C-compact subset of a space X, then (B, X) denotes the degree of C
-compactness of B in X. A space X is called -pseudocompact if X is C
-compact into itself. For each cardinal , we give an example of an -pseudocompact space X such that X × X is not pseudocompact: this answers a question posed by T. Retta in Some cardinal generalizations of pseudocompactness Czechoslovak Math. J. 43 (1993), 385–390. The boundedness of the product of two bounded subsets is studied in some particular cases. A version of the classical Glicksberg's Theorem on the pseudocompactness of the product of two spaces is given in the context of boundedness. This theorem is applied to several particular cases. 相似文献
9.
D. M. Smirnov 《Algebra and Logic》2005,44(2):109-116
Let be the set of all primes,
the field of all algebraic numbers, and Z the set of square-free natural numbers. We consider partially ordered sets of interpretability types such as
, and
, where AD is a variety of -divisible Abelian groups with unique taking of the pth root p(x) for every p ,
is a variety of
-modules over a normal field
, contained in
, and Gn is a variety of n-groupoids defined by a cyclic permutation (12 ...n). We prove that
, and
are distributive lattices, with
and
where
ub and
ubf are lattices (w.r.t. inclusion) of all subsets of the set and of finite subsets of , respectively.Deceased.__________Translated from Algebra i Logika, Vol. 44, No. 2, pp. 198–210, March–April, 2005. 相似文献
10.
On the Harris Recurrence of Iterated Random Lipschitz Functions and Related Convergence Rate Results 总被引:1,自引:0,他引:1
Gerold Alsmeyer 《Journal of Theoretical Probability》2003,16(1):217-247
A result by Elton(6) states that an iterated function system
of i.i.d. random Lipschitz maps F
1,F
2,... on a locally compact, complete separable metric space
converges weakly to its unique stationary distribution if the pertinent Liapunov exponent is a.s. negative and
for some
. Diaconis and Freedman(5) showed the convergence rate be geometric in the Prokhorov metric if
for some p>0, where L
1 denotes the Lipschitz constant of F
1. The same and also polynomial rates have been recently obtained in Alsmeyer and Fuh(1) by different methods. In this article, necessary and sufficient conditions are given for the positive Harris recurrence of (M
n
)
n0 on some absorbing subset
. If
and the support of has nonempty interior, we further show that the same respective moment conditions ensuring the weak convergence rate results mentioned above now lead to polynomial, respectively geometric rate results for the convergence to in total variation or f-norm
f
, f(x)=1+d(x,x
0)
for some (0,p]. The results are applied to various examples that have been discussed in the literature, including the Beta walk, multivariate ARMA models and matrix recursions. 相似文献
11.
This paper examines the distribution of the number, k, of increasing -sequences in a random permutation of
. A new solution is determined based on the compositions of n which requires, at most,
summands. This solution easily yields existing results for the special case
and provides an alternate form for the case
. The expected number of increasing -sequences in a random permutation is determined and it is shown that the limiting distribution is degenerate about 0 for
2$$
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. An alternate algorithm to determine the exact distribution is presented, based on the partitions of n, which is easy to implement and efficient for small n. Applications in non-parametric statistics and graph theory are discussed. 相似文献
12.
Let F(k) denote the k-th
Fibonacci number in the Fibonacci sequence
F(0) := 0, F(1) := 1,..., F(k+1) := F(k-1)+F(k).
Motivated by proposals regarding putative mechanisms
that may be responsible for producing those often observed long repetitive patterns in
genomic DNA, we study in this note the Fibonacci-Cayley index
fcx of positive integers x, i.e.,
the largest integer
for which positive integers a, b
with x = aF(k-1)+bF(k)
exist and show that
holds for the arithmetic mean
of the indices of the smallest and the largest Fibonacci numbers occurring in the Zeckendorf
decomposition
AMS Subject Classification: 11B39, 11A99, 92D20. 相似文献
13.
In the paper, a discrete distribution of the Matsumoto zetafunction is considered. It is proved that the probability measure
, converges weakly as
. 相似文献
14.
We report results of investigations concerning the role of representations of
in the theory of genus-two hyperelliptic functions. We discuss the role of these representations in the classical theory as well as introduce a family of new, naturally covariant
functions. 相似文献
15.
Let X be a topological space, ( ) a net of Borel probability measures on X, and (t) a net in ]0,[ converging to 0. Let
be a set of continuous functions such that for all x X that can be suitably distinguished by some continuous functions from any closed set not containing
contains such a distinguishing function. Assuming that
exists for all
, we give a sufficient condition in order that ( ) satisfies a large deviation principle with powers (t) and not necessary tight rate function. When X is completely regular (not necessary Hausdorff), this condition is also necessary, and so strictly weaker than exponential tightness; this allows us to strengthen Brycs theorem in various ways. We give the general form of a rate function in terms of
. A Prohorov-type theorem with a weaker notion than exponential tightness is obtained, which improves known results. 相似文献
16.
In this paper, we consider the behavior of rectangular partial sums of the Fourier series of continuous functions of several variables with respect to the trigonometric system. The Fourier series is called -convergent if the limit of rectangular partial sums over all indices
for which
for all j and k exists. In the space of arbitrary even dimension 2m we construct an example of a continuous function with an estimate of the modulus of continuity
such that its Fourier series is -divergent everywhere for any
. 相似文献
17.
Small values of
are investigated, using the value distribution results of A. Selberg. This gives an asymptotic formula for
Some related problems involving values of
and gaps between ordinates of consecutive zeros of (s) are also discussed. 相似文献
18.
P. M. G. Manchón 《Czechoslovak Mathematical Journal》2002,52(1):1-9
In this paper we study the hypersurfaces
given as connected compact regular fibers of a differentiable map
, in the cases in which
has finitely many nondegenerate critical points in the unbounded component of
. 相似文献
19.
K. Kido 《Journal of Optimization Theory and Applications》2005,125(3):577-589
Let C be a fixed compact convex subset of
and let xp be the unique minimal p-norm element in C for any
. In this paper, we study the convergence of xp as p or
, respectively. We characterize also the limit point as the minimal element of C with respect to the lexical minimax order relation or the lexical minitotal order relation, respectively.Communicated by D. G. LuenbergerThe author thanks Professor H. Komiya for valuable advice and an anonymous referee for kind comments. 相似文献
20.
Suppose that
(j) is the lag-j autocorrelation of the squared residuals computed from a realization of length n under the assumption that the observations follow a GARCH(1,1) model. We study the asymptotic distribution of the statistics of the form
, where the j are nonnegative summable weights and the matrix
, can be estimated from the data. We show that, under weak assumptions on model errors, the statistic Q
n converges in distribution to
, where the N
i are iid standard normal. We discuss choices of the weights j for which the distribution of Q is tabulated. Our results lead to and provide a rigorous justification for Portmanteau goodness-of-fit tests for GARCH(1,1) specification. 相似文献