共查询到20条相似文献,搜索用时 46 毫秒
1.
Karine Sorlin 《Comptes Rendus Mathematique》2002,334(3):179-184
Let G be a connected reductive group defined over and let F be the corresponding Frobenius endomorphism. Let σ be a quasi-central rational automorphism of G. We define in this article Gelfand–Graev representations of the group when σ is unipotent and when it is semi-simple. We show that they have similar properties to Gelfand–Graev representations of the group GF. To cite this article: K Sorlin, C. R. Acad. Sci. Paris, Ser. I 334 (2002) 179–184. 相似文献
2.
We consider a real semi-simple Lie group G with finite center and a maximal compact sub-group K of G. Let be a Cartan decomposition of G. For x∈G denote ∥x∥ the norm of the -component of x in the Cartan decomposition of G. Let and 1?p,q?∞. In this Note we give necessary and sufficient conditions on such that for all K-bi-invariant measurable function f on G, if ea∥x∥2f∈Lp(G) and then f=0 almost everywhere. To cite this article: S. Ben Farah, K. Mokni, C. R. Acad. Sci. Paris, Ser. I 336 (2003). 相似文献
3.
Suppose G is a separable locally compact group and N is a closed normal subgroup. If the dual N? is smooth and the orbit space is smooth for the natural action of G on , the method of G. W. Mackey (Acta Math.99 (1958), 265–311) gives a fairly simple procedure for constructing the dual ?. In this paper we examine an example which shows that the nonseparable case is much more complicated. In the example, N is abelian, is finite and even when the stabilizer is N there are many irreducible representations of G associated with the same orbit. 相似文献
4.
Let G be a bounded domain in such that is strictly pseudoconvex and U an open subset of bG. We define an open subset of with the property such that the following extension theorem holds true: for every ?∈C(U) there exist two functions such that Φ±|U=? and the graphs Γ(Φ±) of Φ± are Levi-flat over . Moreover, for each such that Φ|U=? and Γ(Φ) is Levi-flat over one has Φ??Φ?Φ+ on . We also show that if G is diffeomorphic to a 3-ball and U is the union of simply-connected domains each of which is contained either in the “upper” or in the “lower” part of bG (with respect to the u-direction), then is the maximal domain of Levi-flat extensions for some function ?∈C(U). To cite this article: N. Shcherbina, G. Tomassini, C. R. Acad. Sci. Paris, Ser. I 337 (2003). 相似文献
5.
Khaled Tounsi 《Comptes Rendus Mathematique》2002,334(9):783-786
We describe a large class of natural star products on the cotangent bundle of a Lie group G and we characterize these star products by integral formulae. To cite this article: K. Tounsi, C. R. Acad. Sci. Paris, Ser. I 334 (2002) 783–786. 相似文献
6.
Alexis Tchoudjem 《Comptes Rendus Mathematique》2002,334(6):441-444
Let G be an adjoint semi-simple group, X its wonderful compactification and its universal covering. One determines the cohomology groups of any invertible sheaf on X, as -modules. To cite this article: A. Tchoudjem, C. R. Acad. Sci. Paris, Ser. I 334 (2002) 441–444. 相似文献
7.
Given a polynomial , we calculate a subspace Gp of the linear space 〈X〉 generated by the indeterminates which is minimal with respect to the property (the algebra generated by Gp, and prove its uniqueness. Furthermore, we use this result to characterize the pairs (P,Q) of polynomials P(X1,…,Xn) and Q(X1,…,Xn) for which there exists an isomorphism T:〈X〉 →〈X〉 that “separates P from Q,” i.e., such that for some k(1<k<n) we can write P and Q as and respectively, where . 相似文献
8.
Steven F Arnold 《Statistics & probability letters》1985,3(5):275-279
Suppose that a statistical decision problem is invariant under a group of transformations g?G. T (X) is equivariant if there exists such that . We show that the minimal sufficient statistic is equivalent and that if T(X) is an equivariant sufficient statistics and d(X) is invariant under G, then is invariant under . 相似文献
9.
Woody Lichtenstein 《Journal of Functional Analysis》1979,34(3):433-455
For a symmetric space of compact type, the highest-weight vectors for representations of G occurring in become heavily concentrated near certain submanifolds of as the highest weight goes to infinity. This fact is applied to obtain estimates for the spectral measures of the operators qλ = PλqPλ, where is an orthogonal projection onto a G-irreducible summand, and q: G/K → is a continuous function acting on by multiplication. 相似文献
10.
Let A be an arbitrary n×n matrix, partitioned so that if A=[Aij], then all submatrices Aii are square. If x is a positive vector, it is well-known that , where , contains all the eigenvalues of A. The purpose of this paper is to give a new definition of the concept of an isolated subregion of G(x). An algorithm is given for obtaining the best such isolated subregion in a certain sense, and examples are given to show that tighter bounds for some eigenvalues of A may be obtained than with previous algorithms. For ease of computation, each subregion Gi(x) is replaced by the union of circular disks centered at the eigenvalues of Aii. 相似文献
11.
Alladi Sitaram 《Journal of Functional Analysis》1978,27(2):179-184
Let G be a semisimple noncompact Lie group with finite center and let K be a maximal compact subgroup. Then W. H. Barker has shown that if T is a positive definite distribution on G, then T extends to Harish-Chandra's Schwartz space 1(G). We show that the corresponding property is no longer true for the space of double cosets . If G is of real-rank 1, we construct liner functionals for each p, 0 < p ? 2, such that but Tp does not extend to a continuous functional on . In particular, if p ? 1, Tv does not extend to a continuous functional on . We use this to answer a question (in the negative) raised by Barker whether for a K-bi-invariant distribution T on G to be positive definite it is enough to verify that . The main tool used is a theorem of Trombi-Varadarajan. 相似文献
12.
We associate to a pseudomanifold X with an isolated singularity a differentiable groupoid G which plays the role of the tangent space of X. We construct a Dirac element D and a Dual Dirac element λ which induce a Poincaré duality in K-theory between the -algebras C(X) and . To cite this article: C. Debord, J.-M. Lescure, C. R. Acad. Sci. Paris, Ser. I 336 (2003). 相似文献
13.
Rudolf Wegmann 《Journal of Mathematical Analysis and Applications》1976,56(1):113-132
For an n × n Hermitean matrix A with eigenvalues λ1, …, λn the eigenvalue-distribution is defined by · number {λi: λi ? x} for all real x. Let An for n = 1, 2, … be an n × n matrix, whose entries aik are for i, k = 1, …, n independent complex random variables on a probability space (Ω, , p) with the same distribution Fa. Suppose that all moments | a | k, k = 1, 2, … are finite, a=0 and | a | 2. Let with complex numbers θσ and finite products Pσ of factors A and (= Hermitean conjugate) be a function which assigns to each matrix A an Hermitean matrix M(A). The following limit theorem is proved: There exists a distribution function G0(x) = G1x) + G2(x), where G1 is a step function and G2 is absolutely continuous, such that with probability converges to G0(x) as n → ∞ for all continuity points x of G0. The density g of G2 vanishes outside a finite interval. There are only finitely many jumps of G1. Both, G1 and G2, can explicitly be expressed by means of a certain algebraic function f, which is determined by equations, which can easily be derived from the special form of M(A). This result is analogous to Wigner's semicircle theorem for symmetric random matrices (E. P. Wigner, Random matrices in physics, SIAM Review9 (1967), 1–23). The examples , , , r = 1, 2, …, are discussed in more detail. Some inequalities for random matrices are derived. It turns out that with probability 1 the sharpened form of Schur's inequality for the eigenvalues λi(n) of An holds. Consequently random matrices do not tend to be normal matrices for large n. 相似文献
14.
Rachel J Pries 《Comptes Rendus Mathematique》2002,335(5):485-487
Consider a wildly ramified G-Galois cover of curves branched at only one point over an algebraically closed field k of characteristic p. In this note, I prove using formal patching that all sufficiently large conductors occur for such covers φ when the Sylow p-subgroups of G have order p. To cite this article: R.J. Pries, C. R. Acad. Sci. Paris, Ser. I 335 (2002) 485–487. 相似文献
15.
Hélène Airault 《Comptes Rendus Mathematique》2002,334(9):787-792
Let be the infinite product of countably many copies of . A Borelian probability measure on the infinite dimensional topological space which is unitarizing for the canonical representation of the infinite dimensional Heisenberg algebra is a Gaussian measure on . To cite this article: H. Airault, C. R. Acad. Sci. Paris, Ser. I 334 (2002) 787–792. 相似文献
16.
17.
Rachel J Pries 《Comptes Rendus Mathematique》2002,335(5):481-484
Consider a wildly ramified G-Galois cover of curves branched at only one point over an algebraically closed field k of characteristic p. For any p-pure group G whose Sylow p-subgroups have order p, I show the existence of such a cover with small conductor. The proof uses an analysis of the semi-stable reduction of families of covers. To cite this article: R.J. Pries, C. R. Acad. Sci. Paris, Ser. I 335 (2002) 481–484. 相似文献
18.
Ramzi May 《Comptes Rendus Mathematique》2003,336(9):731-734
Let be a maximal solution of the Navier–Stokes equations. We prove that u is C∞ on and there exists a constant , which depends only on n, such that if is finite then, for all we have To cite this article: R. May, C. R. Acad. Sci. Paris, Ser. I 336 (2003). 相似文献
19.
We present solutions of seven graph equations involving the line graph, complement and n-th power operations. One such equation generalizes a result of M. Aigner. In addition, some comments are made about graphs satisfying . 相似文献
20.
Harry Dym 《Journal of Functional Analysis》1978,28(1):33-57
Let PT denote the orthogonal projection of L2(R1, dΔ) onto the space of entire functions of exponential type ? T which are square summable on the line with respect to the measure , and let G denote the operator of multiplication by a suitably restricted complex valued function g. It is shown that if is summable, if is locally summable, and if belongs to the span in L∞ of e?iyTH∞:T ? 0, in which h is chosen to be an outer function and h#(γ) agrees with the complex conjugate of h(γ) on the line, then exists and is independent of h for every positive integer n. This extends the range of validity of a formula due to Mark Kac who evaluated this limit in the special case h = 1 using a different formalism. It also extends earlier results of the author which were established under more stringent conditions on h. The conclusions are based in part upon a preliminary study of a more general class of projections. 相似文献