共查询到20条相似文献,搜索用时 62 毫秒
1.
We use minimal Legendrian submanifolds in spheres to construct examples of absolutely area-minimizing cones and we prove a result about Legendrian 2-tori in S5. 相似文献
2.
Let S be the free semigroup with a finite or countably infinite set of generators plus an identity. It is shown that there is a natural involution 1 on the convolution Banach algebra l1(S) such that (l1(S), 1) has a separating family of finite-dimensional star representations. The star representations of the l1-algebra of some other semigroups are also considered. The spectrum of every element of l1(S) which is not a scalar multiple of the identity is shown to be a connected set with interior. 相似文献
3.
Tristan Rivière 《Annals of Global Analysis and Geometry》2000,18(5):517-528
We prove that the maps from S
2 intoS
1 having a finite number of isolated singularities ofdegree ±1 are dense for the strong topology inH
1/2(S
2, S
1). We also prove that smooth maps are densein H
1/2(S
2, S
1)for the sequentially weak topology andthat this is no more the case in H
s
(S
2, S
1) for s> 1/2. 相似文献
4.
Shizan Fang 《Journal of Functional Analysis》2004,216(1):22-46
The Brownian motion with respect to the metric H3/2 on Diff(S1) has been constructed. It is realized on the group of homeomorphisms Homeo(S1). In this work, we shall resolve the stochastic differential equations on Homeo(S1) for a given drift Z. 相似文献
5.
Carlos Conca Jeannine Saint Jean Paulin 《Journal of Mathematical Analysis and Applications》2003,285(1):17-36
The L2- and H1-approximate controllability and homogenization of a semilinear elliptic boundary-value problem is studied in this paper. The principal term of the state equation has rapidly oscillating coefficients and the control region is locally distributed. The observation region is a subset of codimension 1 in the case of L2-approximate controllability or is locally distributed in the case of H1-approximate controllability. By using the classical Fenchel-Rockafellar's duality theory, the existence of an approximate control of minimal norm is established by means of a fixed point argument. We consider its asymptotic behavior as the rapidly oscillating coefficients H-converge. We prove its convergence to an approximate control of minimal norm for the homogenized problem. 相似文献
6.
B. Helffer 《Journal of Functional Analysis》2009,257(10):3043-3081
We consider a periodic magnetic Schrödinger operator Hh, depending on the semiclassical parameter h>0, on a noncompact Riemannian manifold M such that H1(M,R)=0 endowed with a properly discontinuous cocompact isometric action of a discrete group. We assume that there is no electric field and that the magnetic field has a periodic set of compact magnetic wells. We suppose that the magnetic field vanishes regularly on a hypersurface S. First, we prove upper and lower estimates for the bottom λ0(Hh) of the spectrum of the operator Hh in L2(M). Then, assuming the existence of non-degenerate miniwells for the reduced spectral problem on S, we prove the existence of an arbitrarily large number of spectral gaps for the operator Hh in the region close to λ0(Hh), as h→0. In this case, we also obtain upper estimates for the eigenvalues of the one-well problem. 相似文献
7.
《Topology》2004,43(3):599-618
We continue the analysis started by Abreu, McDuff and Anjos of the topology of the group of symplectomorphisms of S2×S2 when the ratio of the area of the two spheres lies in the interval (1,2]. We express the group, up to homotopy, as the pushout (or amalgam) of certain of its compact Lie subgroups. We use this to compute the homotopy type of the classifying space of the group of symplectomorphisms and the corresponding ring of characteristic classes for symplectic fibrations. 相似文献
8.
Earl S Kramer Spyros S Magliveras Dale M Mesner 《Journal of Combinatorial Theory, Series A》1980,29(2):166-173
There exist 13 mutually disjoint resolutions of the Steiner system S(5, 8, 24). There also exist nine nonisomorphic mutually disjoint resolutions of S(5, 8, 24) where three of the resolutions have the same L2(23) as an automorphism group and the other six have the same affine group C2311 as an automorphism group. A resolution of S(5, 8, 24) using a group of order 21 is displayed and a 13-dimensional Room-type design is mentioned. 相似文献
9.
A Ghosh 《Journal of Number Theory》1983,17(1):93-102
Asymptotic formulae for the mean values of |S(t)|λ, where λ is any nonnegative number are proved,. These are then used with λ ∈ , to obtain information of the distribution of |S(t)|. 相似文献
10.
Richard Rochberg 《Journal of Functional Analysis》1973,13(2):154-172
Let A(S) be the sup-normed Banach algebra of analytic functions with continuous boundary values on the compact bordered Riemann surface S.For (?) in , the colength of (?) is defined by . Colength is shown to induce a norm on the cohomology group H1(S,R) dual to the norm induced on the homology group H1(S,R) by harmonic length, or, equivalently, dual to the norm on Re A(S)⊥.The existence and uniqueness of extremal functions for the colength functional is demonstrated. The aforementioned norms are shown to determine the conformal structure of S (up to reflection) and to be related to the mapping properties of S. 相似文献
11.
In this paper,optimize-then-discretize,variational discretization and the finite volume method are applied to solve the distributed optimal control problems governed by a second order hyperbolic equation.A semi-discrete optimal system is obtained.We prove the existence and uniqueness of the solution to the semidiscrete optimal system and obtain the optimal order error estimates in L ∞(J;L 2)-and L ∞(J;H 1)-norm.Numerical experiments are presented to test these theoretical results. 相似文献
12.
We prove that in any nonzero cohomology class ξ∈H1(M;R) there always exists a closed 1-form having at most one zero. 相似文献
13.
In this paper we first introduce Ls(μ)-averaging domains which are generalizations of Ls-averaging domains introduced by S.G. Staples. We characterize Ls(μ)-averaging domains using the quasihyperbolic metric. As applications, we prove norm inequalities for conjugate A-harmonic tensors in Ls(μ)-averaging domains which can be considered as generalizations of the Hardy and Littlewood theorem for conjugate harmonic functions. Finally, we give applications to quasiconformal and quasiregular mappings. 相似文献
14.
S.N.M. Ruijsenaars 《Journal of Functional Analysis》1979,33(1):47-57
It is proved that the classical S-operator for relativistic spin-0 and spin- particles in time-dependent external fields is gauge invariant, and that S+- and S?+ are entire functions of the coupling constant in the Hilbert-Schmidt norm. As a result the Fock space S-operator exists for any real value of the coupling constant, and is gauge invariant. The external fields and the gauge function are assumed to be real-valued resp. complex-valued functions in S(R4). 相似文献
15.
Qing-Ming Cheng 《Commentarii Mathematici Helvetici》1996,71(1):60-69
In this paper, we prove that ifM is ann-dimensional closed minimal hypersurface with two distinct principal curvatures of a unit sphereS n+1 (1), thenS=n andM is a Clifford torus ifn≤S≤n+[2n 2(n+4)/3(n(n+4)+4)], whereS is the squared norm of the second fundamental form ofM. 相似文献
16.
After the change of variables Δi = γi ? δi and xi,i + 1 = δi ? δi + 1 we show that the invariant polynomials μG(n)q(, Δi, ; , xi,i+1,) characterizing U(n) tensor operators 〈p, q,…, q, 0,…, 0〉 become an integral linear combination of Schur functions Sλ(γ ? δ) in the symbol γ ? δ, where γ ? δ denotes the difference of the two sets of variables {γ1 ,…, γn} and {δ1 ,…, δn}. We obtain a similar result for the yet more general bisymmetric polynomials mμG(n)q(γ1 ,…, γn; δ1 ,…, δm). Making use of properties of skew Schur functions and Sλ(γ ? δ) we put together an umbral calculus for mμG(n)q(γ; δ). That is, working entirely with polynomials, we uniquely determine mμG(n)q(γ; δ) from mμG(n)q ? 1(γ; δ) and combinatorial rules involving Ferrers diagrams (i.e., partitions), provided that n ≥ (μ + 1)q. (This restriction does not interfere with writing the general case of mμG(n)q(γ; δ) as a linear combination of Sλ(γ ? δ).) As an application we deduce “conjugation” symmetry for nμG(n)q(γ; δ) from “transposition” symmetry by showing that these two symmetries are equivalent. 相似文献
17.
18.
If v is a norm on n, let H(v) denote the set of all norm-Hermitians in nn. Let S be a subset of the set of real diagonal matrices D. Then there exists a norm v such that S=H(v) (or S = H(v)∩D) if and only if S contains the identity and S is a subspace of D with a basis consisting of rational vectors. As a corollary, it is shown that, for a diagonable matrix h with distinct eigenvalues λ1,…, λr, r?n, there is a norm v such that h ∈ H(v), but hs?H(v), for some integer s, if and only if λ2–λ1,…, λr–λ1 are linearly dependent over the rationals. It is also shown that the set of all norms v, for which H(v) consists of all real multiples of the identity, is an open, dense subset, in a natural metric, of the set of all norms. 相似文献
19.
S-domains and strong S-rings are studied extensively with special emphasis on integral and polynomial ring extensions. The main theorem of this paper is that for a Prüfer domain R, the polynomial ring R[X1,…Xn] in finitely many indeterminates is a strong S-domain. We also prove that any Prüfer υ-multiplication domain is an S-domain. 相似文献
20.
J. Extremera 《Journal of Functional Analysis》2003,197(1):212-227
Let G be a compact group. If the trivial representation of G is not weakly contained in the left regular representation of G on L02(G) and X is either Lp(G) for 1<p?∞ or C(G), then we show that every complete norm |·| on X that makes translations from (X,|·|) into itself continuous is equivalent to ||·||p or ||·||∞ respectively. If 1<p?∞ and every left invariant linear functional on Lp(G) is a constant multiple of the Haar integral, then we show that every complete norm |·| on Lp(G) that makes translations from (Lp(G),|·|) into itself continuous and that makes the map t?Lt from G into bounded is equivalent to ||·||p. 相似文献