共查询到20条相似文献,搜索用时 31 毫秒
1.
We prove that if aC
1 smooth change of variable : generates a bounded composition operatorff° in the spaceA
p()=L
p
,p2, then is linear (affine).We also prove that for a nonlinearC
1 mapping , the norms of exponentialse
i as Fourier multipliers inL
p
() tend to infinity (,||). In both results the condition C
1 is sharp, it cannot be replaced by the Lipschitz condition. 相似文献
2.
We investigate the multidimensional equations
j=1
q
Aj(x)y(x+e
j
)=f(x),e
j
n wherex n andA
j
: n Hom(
p
,
m
),f : n m are given maps. Sufficient conditions for smooth and analytic solvability for anyf C
k
,k are found.Research partially supported by the Israel Ministry of ScienceAMS classification 39B Functional equations 相似文献
3.
Dr. J. D. Stegeman 《Monatshefte für Mathematik》1976,82(4):337-340
It is proved that closed subgroups of
n
are Wiener-Ditkin sets for the Beurling algebrasL
1
(
n
), <1. 相似文献
4.
Hans-Heinrich Kairies 《Aequationes Mathematicae》1996,51(1-2):115-128
Summary The following Artin type characterization of : + + is proved: Assume thatf: + + satisfies the Gauss multiplication formula for some fixedp 2,f is absolutely continuous on [l/p, 1 + ] for some > 0 and lim
x 0
xf(x) = 1. Thenf(x) = (x) forx > 0.The optimality of this result is checked by means of counterexamples. For instance, it is shown that the result is no longer true, if f is absolutely continuous is replaced by f is continuous and of finite variation. 相似文献
5.
Joaquin Ortega 《Probability Theory and Related Fields》1982,59(2):169-177
Summary Let X={X(t), t
N} be a centred Gaussian random field with covariance X(t)X(s)=r(t–s) continuous on N×N and r(0)=1. Let (t,s)=((X(t)–X(s))
2)1/2; (t,s) is a pseudometric on N. Assume X is -separable. Let D
1 be the unit cube in N and for 0<k, D
k= {xN: k
–1
xD1}, Z(k)=sup{X(t),tD
k}. If X is sample continuous and ¦r(t)¦ =o(1/log¦t¦) as ¦t¦8 then Z(k)-(2Nlogk)
1/20 as k a.s. 相似文献
6.
For C a bounded, injective operator with dense image, we define a C-regularized spectral distribution. This produces a functional calculus, f f(B), from C() into the space of closed densely defined operators, such that f(B)C is bounded when f has compact support. As an analogue of Stone's theorem, we characterize certain regularized spectral distributions as corresponding to generators of polynomially bounded C-regularized groups. We represent the regularized spectral distribution in terms of the regularized group and in terms of the C-resolvent. Applications include the Schrödinger equation with potential, and symmetric hyperbolic systems, all on Lp(n) (1p<), C
o(n), BUC(n), or any space of functions where translation is a bounded strongly continuous group. 相似文献
7.
An optimization problem of interactive inhomogenous flows (Steiner multicommodity network flow problem) is formulated. The problem's main characteristic is a fixed charge change when combining multicommodity communications. In this paper we propose a method for solving this problem which, in order to restrict the search on the feasible domain, reduces the original problem to a concave programming problem in the form: min {f(x)|xX} wheref:n is a concave function, andX
0
n
is a flow polytope defined by network transportation constraints. For practical large-scale problems arising from planning transportation networks on inhomogeneous surfaces defined by a digital model, a method of local optimization over a flow polytope vertex set is proposed, which is far more effective in comparison with the Gallo and Sodini method under polytope strong degeneracy conditions. 相似文献
8.
Pierre Maréchal 《Set-Valued Analysis》2005,13(2):197-212
Given a convex subset C of n, the set-valued mapping C (where 0C is, by convention, the recession cone of C) is increasing on + if and only if C contains the origin, and decreasing on + if and only if C is contained in its recession cone. This simple fact enables us to define a binary operation which combines a concave or convex function on m with a convex subset of n to produce a convex subset of n+m. This binary operation is the set theoretic counterpart of a functional operation introduced by the author. In this paper, we present a detailed study of the class of convex subsets which are contained in their recession cones, and we establish some remarkable properties of our binary operation.Mathematics Subject Classifications (2000) 26A51, 26B25, 26E25. 相似文献
9.
Maria Aparecida Soares Ruas Raimundo Nonato Araújo dos Santos 《manuscripta mathematica》2005,117(2):207-218
In this paper we study Milnor fibrations associated to real isolated singularities defined by map-germs f: (m,0)(2,0). The main result relates the existence of the Milnor fibration with the (C)-regularity of the family of hypersurfaces with isolated singularity obtained by projecting f into the family L– of all lines through the origin in the plane 2. 相似文献
10.
Dr. Peter Schöpf 《Monatshefte für Mathematik》1977,83(4):331-337
For any set ofn+1 pointsx
1, ...,x
n+1F we denote byv(C(x
1,...,x
n+1)) then-dimensional oriented volume of the convex hullC(x
1,...,x
n+1) of these points. With a fixed symmetric functionf: >> strictly monotone increasing on the nonnegative real line, we consider the real functional RODEL on the set of all convex bodiesK of n with absolute volume |v(K)|=1 and assert, that it takes its minimal value on the ellipsoids with absolute volume 1. 相似文献
11.
S. Helbig 《Mathematical Methods of Operations Research》1991,35(3):197-220
A vector optimization problem is given by a feasible setZ
n
, a vector-valued objective functionf:
n
l
, and an ordering coneC
l
. We perturb the ordering cone in such a way that the weakly efficient points of the perturbed vector optimization problem given byZ, f, and the perturbed cone are efficient points of the original problem. Especially this means that scalarization methods, which compute in general only weakly efficient points, determine efficient points of the original problem, when they were applied to the perturbed problem.It turns out that the efficient points are the limits of weakly efficient points of the perturbed problems, letting the perturbation tend to zero. On the basis of this, a reference point algorithm is formulated. Finally, we apply this algorithm to a structural optimization problem. 相似文献
12.
Markus Stroppel 《Geometriae Dedicata》1993,45(1):93-99
In [4], K. Strambach describes a 2-dimensional stable plane
admitting =SL2 as a group of automorphisms such that there exists no -equivarient embedding into a 2-dimensional projective plane. R. Löwen [3] has given a 4-dimensional analogue
, admitting =SL2. He posed the question whether there are embeddings of Strambach's plane
into
. We show that such embeddings exist, in fact we determine all -equivariant embeddings of 2-dimensional stable planes admitting as atransitive group of automorphisms. 相似文献
13.
G. G. Oniani 《Mathematical Notes》2005,77(1-2):84-89
It is proved that for any n 2 there exists continuous function f : n which is differentiable almost everywhere, but has no strong gradient almost everywhere.Translated from Matematicheskie Zametki, vol. 77, no. 1, 2005, pp. 93–98.Original Russian Text Copyright © 2005 by G. G. Oniani.This revised version was published online in April 2005 with a corrected issue number. 相似文献
14.
Salvatore A. Marano 《Set-Valued Analysis》1994,2(4):545-558
Let be a bounded domain in
n
(n 3) having a smooth boundary, letY be a closed, connected and locally connected subset of
h
, letf be a real-valued function defined on ×
h
×
nh
×Y, and letL be a linear, second-order elliptic operator. In this paper, the existence of strong solutionsu W
2,p
(,
h
) W
0
1,p
(,
h
) (n<p<+) to the implicit elliptic equationf(x, u, Du, Lu)=0, whereu=(u
1,u
2, ...,u
h
),Du=(Du
1,Du
2, ...,Du
h
) andLu=(Lu
1,Lu
2, ...,Lu
h
), is established. The abstract framework where the equation is studied is that of set-valued analysis.Dedicated to Professor G. Pulvirenti on the occasion of his sixtieth birthday 相似文献
15.
Peter Hellekalek 《Monatshefte für Mathematik》1992,114(3-4):199-208
Leta be irrational and letf:[0,1] be Riemann-integrable with integral zero. Letf
n
(x) denote the Weyl sumf
n
(x):=
k=0
n–1
f({x
k>}),x/[0,1[,n. We prove criteria for the boundedness of the sequence (f
n
)
n1 and discuss the relation of this question to irregularities of the distribution of sequences. 相似文献
16.
J. Matkowski 《Aequationes Mathematicae》1990,40(1):168-180
Summary The main result says that, iff: + + satisfies the functional inequalityaf(s) + bf(t) f (as + bt) (s,t 0) for somea, b such that 0 <a < 1 <a + b, thenf(t) = f(1)t, (t 0). A relevant result for the reverse inequality is also discussed. Applying these results we determine the form of all functionsf:
k
+
+ satisying the above inequalities. This leads to a characterization of both concave and convex functions defined on
+
k–1
, to a notion of conjugate functions and to a general inequality which contains Hölder's and Minkowski's inequalities as very special cases. 相似文献
17.
Peter Schroth 《Aequationes Mathematicae》1985,28(1):252-254
LetG be a vector space over the field of rational numbers andf, g:G -linear mappings. equipped with the usual norm topology. Denote by
f
,
g
the initial topologies onG induced byf respectivelyg.Then the following result holds: If there is a nonvoid open setU whose complement contains at least one inner point such thatf
–1
U
g
, then there is ac withf=cg. In particular, iff0, the topologies coincide.Furthermore, a -linear mappingh: (G,
f
)(G,
g
) is continuous if and only if there is a real constantc withg
o
h=cf.Dedicated to Professor János Aczél on his 60th birthday 相似文献
18.
Letp(1, ). In this paper, the authors investigate the uniformL
p
(
n
) in of the oscillatory singular integral operatorT
defined by
where , is a real analytic function or a real-C
function on
n
×
n
, C
0
(
n
×
n
) andk is a variable Calderón-Zygmund kernel. Moreover, the uniform boundedness in of the commutators generated byT
and BMO(
n
) functions onL
p
(
n
) is also obtained.The research is supported in part by the NNSF and the SEDF of China. 相似文献
19.
J. -B. Hiriart-Urruty 《Journal of Optimization Theory and Applications》1986,48(1):127-140
Given a convex functionf:
p
×
q
(–, +], the marginal function is defined on
p
by (x)=inf{f(x, y)|y
q
}. Our purpose in this paper is to express the approximate first-order and second-order directional derivatives of atx
0 in terms of those off at (x
0,y
0), wherey
0 is any element for which (x
0)=f(x
0,y
0).The author is indebted to one referee for pointing out an inaccuracy in an earlier version of Theorem 4.1. 相似文献
20.
Carlos Gutierrez Marco-Antonio Teixeira 《Bulletin of the Brazilian Mathematical Society》1995,26(1):57-66
Let >0 andX be aC
1 vector field on the plane such that: (i) for allq2, Det(DX(q))>0; and (ii) for allp2, with p, Trace(D(X(p))<0. IfX has a singularity and
2 Trace(DX)dxdy is less than 0 (resp. greater or equal than 0), then the point at infinity of the Riemann sphere 2{} is a repellor (resp. an attractor) ofX. 相似文献