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1.
We prove that if a symmetric submarkovian semigroup (T
t
)
t>0
satisfies an estimate of the form
where ϕ is an increasing C
1
-diffeomorphism of [0,+∞) with subexponential growth, then a suitable function of its infinitesimal generator is bounded from
L
p
(M) to L
q
(M) for 1<p<q<+∞, and that a weak converse holds true if p=2. In the special case where ϕ(t)=Ct
μ
for small t and ϕ(t)=C′ exp(ct
ν
) for large t, μ>0, c>0, 0<ν<1, one obtains a sharp and explicit result, which applies for instance to sublaplacians on solvable unimodular Lie
groups with exponential growth.
Received: 29 June 2001 /
Published online: 1 April 2003
Mathematics Subject Classifications (2000): 47D06, 58J35, 43A80
Research supported by the Italian M.U.R.S.T., fondi 60%, the Italian GNAFA, and the European Commission (European TMR Network
``Harmonic Analysis' 1998–2001, Contract ERBFMRX-CT97-0159). 相似文献
2.
B. de Malafosse 《Acta Mathematica Hungarica》2009,122(3):217-230
We deal with the sum of sequence spaces. Then we apply these results to characterize matrix transformations mapping between
s
h,l
(λ, μ) = s
α
0((Δ − λI)
h
) + s
β
(c)((Δ − μI)
l
) and s
γ
. Among other things the aim of this paper is to reduce the set (s
h,l
(λ, μ), s
γ
to a set of the form S
τ,γ
.
相似文献
3.
X. J. Long 《Journal of Optimization Theory and Applications》2011,148(1):197-208
The purpose of this paper is to consider a class of nondifferentiable multiobjective fractional programming problems in which
every component of the objective function contains a term involving the support function of a compact convex set. Based on
the (C,α,ρ,d)-convexity, sufficient optimality conditions and duality results for weakly efficient solutions of the nondifferentiable
multiobjective fractional programming problem are established. The results extend and improve the corresponding results in
the literature. 相似文献
4.
For a bounded system of linear equalities and inequalities, we show that the NP-hard ℓ
0-norm minimization problem is completely equivalent to the concave ℓ
p
-norm minimization problem, for a sufficiently small p. A local solution to the latter problem can be easily obtained by solving a provably finite number of linear programs. Computational
results frequently leading to a global solution of the ℓ
0-minimization problem and often producing sparser solutions than the corresponding ℓ
1-solution are given. A similar approach applies to finding minimal ℓ
0-solutions of linear programs. 相似文献
5.
For fixed generalized reflection matrix P, i.e. P
T
= P, P
2 = I, then matrix X is said to be generalized bisymmetric, if X = X
T
= PXP. In this paper, an iterative method is constructed to find the generalized bisymmetric solutions of the matrix equation A
1
X
1
B
1 + A
2
X
2
B
2 + ⋯ + A
l
X
l
B
l
= C where [X
1,X
2, ⋯ ,X
l
] is real matrices group. By this iterative method, the solvability of the matrix equation can be judged automatically. When
the matrix equation is consistent, for any initial generalized bisymmetric matrix group , a generalized bisymmetric solution group can be obtained within finite iteration steps in the absence of roundoff errors,
and the least norm generalized bisymmetric solution group can be obtained by choosing a special kind of initial generalized
bisymmetric matrix group. In addition, the optimal approximation generalized bisymmetric solution group to a given generalized
bisymmetric matrix group in Frobenius norm can be obtained by finding the least norm generalized bisymmetric solution group of the new matrix equation
, where . Given numerical examples show that the algorithm is efficient.
Research supported by: (1) the National Natural Science Foundation of China (10571047) and (10771058), (2) Natural Science
Foundation of Hunan Province (06JJ2053), (3) Scientific Research Fund of Hunan Provincial Education Department(06A017). 相似文献
6.
Donald I. Cartwright 《Monatshefte für Mathematik》2001,247(1):93-109
To any locally finite thick building of type there is naturally associated a commutative algebra of operators. When is constructed from a local field F with local ring , and , then is isomorphic to the convolution algebra of compactly supported bi-K-invariant functions on PGL(n+1,F). We give a proof, valid for any , that the multiplicative functionals on may all be expressed in terms of Hall–Littlewood polynomials. Regarding as a subalgebra of the C *-algebra of bounded operators on the space of square summable functions on the vertex set of , we find the spectrum of the C *-algebra , the closure of . This generalizes results obtained in [3] when n = 1 and in [5] when n = 2. 相似文献
7.
In this paper two so-called regularizedGreen’s functions are introduced to derive the optimal maximum norm error estimates for the unknown function and the adjoint vector-valued
function for mixed finite element methods of Laplacian operator. One contribution of the paper is a demonstration of how the
boundedness of L1—norm estimate for the secondGreen’s function λ2 and the optimal maximum norm error estimate for the adjoint vector-valued function are proved. These results are seemed to
be new in the literature of the mixed finite element methods. 相似文献
8.
We prove that the quasi-Banach spaces 1 (p) and p (1), 0 < p < 1 have a unique unconditional basis up to permutation 相似文献
9.
10.
11.
Yong Zhou 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2009,11(3):191-204
Considering the Navier–Stokes equations in
W ì \mathbbRn\Omega \subset {\mathbb{R}}^n, we prove the asymptotic stability for weak solutions in the marginal class u ∈ C
B
(0, ∞; L
n
) with arbitrary initial and external perturbations. 相似文献
12.
本文首先给出(α,β)-γ开集定义,获得了(α,β)-γ开集性质;然后引入了(α,β)-γ-Ti空间和(α,β)-γ-Ti*空间概念(i=0,1/2,1,2,5/2),并得到它们更广泛的拓扑性质. 相似文献
13.
V. Yu. Gubarev 《Siberian Mathematical Journal》2009,50(3):395-404
We take the exterior power ℝ4 ∧ ℝ4 of the space ℝ4, its mth symmetric power V = S
m
(∧2ℝ4) = (ℝ4 ∧ ℝ4) ∨ (ℝ4 ∧ ℝ4) ∨ ... ∨(ℝ4 ∧ ℝ4), and put V
0 = L((x ∧ y)∨ ... ∨(x ∧ y): x, y ∈ ℝ4). We find the dimension of V
0 and an algorithm for distinguishing a basis for V
0 efficiently. This problem arose in vector tomography for the purpose of reconstructing the solenoidal part of a symmetric
tensor field.
Original Russian Text Copyright ? 2009 Gubarev V. Yu.
The author was supported by the State Maintenance Program for the Leading Scientific Schools of the Russian Federation (Grant
NSh-344.2008.1).
__________
Novosibirsk. Translated from Sibirskiĭ Matematicheskiĭ Zhurnal, Vol. 50, No. 3, pp. 503–514, May–June, 2009. 相似文献
14.
O. Yu. Teplins’kyi 《Ukrainian Mathematical Journal》2011,62(8):1267-1284
We prove the existence of two real-analytic diffeomorphisms of the circle with break of the same size and an irrational rotation
number of semibounded type that are not C
1+γ
-smoothly conjugate for any γ > 0. In this way, we show that the previous result concerning the C
1-smoothness of conjugacy for these mappings is the exact estimate of smoothness for this conjugacy. 相似文献
15.
In this paper, we study a class of Finsler metrics in the form
, where
is a Riemannian metric, β = b
i
y
i
is a 1-form, and ε and k ≠ 0 are constants. We obtain a sufficient and necessary condition for F to be locally projectively flat and give the non-trivial special solutions. Moreover, it is proved that such projectively
flat Finsler metrics with the constant flag curvature must be locally Minkowskian. 相似文献
16.
In the present paper, for a boundary value problem with noncoordinated degeneration of the data and a singularity in the solution,
we show that the R
ν
-generalized solution belongs to the weighted space W
2,ν+gb
2+κ+1/κ+2 (Ω, δ)(κ > 0).
Original Russian Text ? V.A. Rukavishnikov, E.V. Kuznetsova, 2009, published in Differentsial’nye Uravneniya, 2009, Vol. 45,
No. 6, pp. 894–898. 相似文献
17.
Carlos Rito 《Geometriae Dedicata》2012,157(1):319-330
We study surfaces of general type S with p
g
= 0 and K
2 = 3 having an involution i such that the bicanonical map of S is not composed with i. It is shown that, if S/i is not rational, then S/i is birational to an Enriques surface or it has Kodaira dimension 1 and the possibilities for the ramification divisor of
the covering map S → S/i are described. We also show that these two cases do occur, providing an example. In this example S has a hyperelliptic fibration of genus 3 and the bicanonical map of S is of degree 2 onto a rational surface. 相似文献
18.
Sharp estimates are obtained for the convergence rate of double Fourier series in terms of general orthogonal polynomials
in some classes of functions and for the Kolmogorov N-widths of these classes. These results find applications in numerical analysis.
Original Russian Text ? V.A. Abilov, M.K. Kerimov, 2009, published in Zhurnal Vychislitel’noi Matematiki i Matematicheskoi
Fiziki, 2009, Vol. 49, No. 8, pp. 1364–1368. 相似文献
19.
M. H. M. Rashid 《Ukrainian Mathematical Journal》2012,63(8):1256-1267
If T (or T*) is an algebraically wF(p, r, q) operator with p, r > 0 and q ≥ 1 acting in an infinite-dimensional separable Hilbert space, then we prove that Weyl’s theorem holds for f(T) for any f ∈ Hol(σ(T)), where Hol(σ(T)) is the set of all analytic functions in an open neighborhood of σ(T). Moreover, if T* is a wF(p, r, q) operator with p, r > 0 and q ≥ 1, then the a-Weyl’s theorem holds for f(T). In addition, if T (or T*) is an algebraically wF(p, r, q) operator with p, r > 0 and q ≥ 1, then we establish the spectral mapping theorems for the Weyl spectrum and for the essential approximate point spectrum
of T for any f ∈ Hol(σ(T)), respectively. Finally, we examine the stability of Weyl’s theorem and the a-Weyl’s theorem under commutative perturbations
by finite-rank operators. 相似文献
20.
V. V. Ryzhikov 《Functional Analysis and Its Applications》2009,43(2):155-157
If an ergodic automorphism T of a probability space is not partially rigid, then for any numbers a ∈ (0, 1) and ɛ > 0 there exists a set A such that all sets T
i
A, i > 0, are pairwise ɛ-independent.
__________
Translated from Funktsional’nyi Analiz i Ego Prilozheniya, Vol. 43, No. 2, pp. 88–91, 2009
Original Russian Text Copyright ? by V. V. Ryzhikov
This research was carried out under the Program for Support of Leading Scientific Schools in the Russian Federation (grant
no. 6849.2006.1). 相似文献