共查询到20条相似文献,搜索用时 78 毫秒
1.
We present a characterization of ideal knots, i.e., of closed knotted curves of prescribed thickness with minimal length, where we use the notion of global curvature for the definition of thickness. We show with variational methods that for an ideal knot
, the normal vector
at a curve point
is given by the integral over all vectors
against a Radon measure, where
realizes the given thickness. As geometric consequences we obtain in particular, that points without contact lie on straight segments of
, and for points
with exactly one contact point
we have that
points exactly into the direction of
Moreover, isolated contact points lie on straight segments of
, and curved arcs of
consist of contact points only, all realizing the prescribed thickness with constant (maximal) global curvature.Received: 1 January 2003, Accepted: 12 March 2003, Published online: 1 July 2003Mathematics Subject Classification (2000):
53A04, 57M25, 74K05, 74M15, 92C40 相似文献
2.
Given an integer polyhedron
, an integer point
, and a point
, the primal separation problem is the problem of finding a linear inequality which is valid for P
I
, violated by x
*, and satisfied at equality by
. The primal separation problem plays a key role in the primal approach to integer programming. In this paper we examine the complexity of primal separation for several well-known classes of inequalities for various important combinatorial optimization problems, including the knapsack, stable set and travelling salesman problems.Received: November 2002, Revised: March 2003, 相似文献
3.
Angela Pistoia Olivier Rey 《Calculus of Variations and Partial Differential Equations》2003,18(3):243-251
Let
,
, be a bounded domain as defined by Flucher, Garroni and Müller [6], which has a singular point
such that the Robins function achieves its infimum at
. Considering the elliptic problem
in
; u = 0 on
, with p = (N + 2)/(N-2),
, and
a minimizing solution of
,
concentrates at
as
goes to zero.Received: 15 September 2002, Accepted: 5 November 2002, Published online: 16 May 2003Mathematics Subject Classification:
35J65Angela Pistoia: The author is supported by M.U.R.S.T., project Metodi variazionali e topologici nello studio di fenomeni non lineari 相似文献
4.
Relaxation problems for a functional of the type
are analyzed, where
is a bounded smooth open subset of
and g is a Carathéodory function. The admissible functions u are forced to satisfy a pointwise gradient constraint of the type
for a.e.
being, for every
, a bounded convex subset of
, in general varying with x not necessarily in a smooth way. The relaxed functionals
and
of G obtained letting u vary respectively in
, the set of the piecewise C
1-functions in
, and in
in the definition of G are considered. For both of them integral representation results are proved, with an explicit representation formula for the density of
. Examples are proposed showing that in general the two densities are different, and that the one of
is not obtained from g simply by convexification arguments. Eventually, the results are discussed in the framework of Lavrentieff phenomenon, showing by means of an example that deep differences occur between
and
. Results in more general settings are also obtained.Received: 18 December 2002, Accepted: 18 November 2003, Published online: 16 July 2004Mathematics Subject Classification (2000):
49J45, 49J10, 49J53This work is part of the European Research Training Network Homogenization and Multiple Scales (HMS 2000), under contract HPRN-2000-00109. It is also part of the 2003-G.N.A.M.P.A. Project Metodi Variazionali per Strutture Sottili, Frontiere Oscillanti ed Energie Vincolate. 相似文献
5.
Given an almost complex structure J in a cylinder of
(p > 1) together with a compatible symplectic form
and given an arbitrary J-holomorphic curve
without boundary in that cylinder, we construct an holomorphic perturbation of
, for the canonical complex structure J
0 of
, such that the distance between these two curves in W
1,2 and
norms, in a sub-cylinder, are controled by quantities depending on J,
and by the area of
only. These estimates depend neither on the topology nor on the conformal class of
. They are key tools in the recent proof of the regularity of 1-1 integral currents in [RT].Received: 2 October 2003, Accepted: 18 November 2003, Published online: 25 February 2004 相似文献
6.
P. Courilleau J. Mossino 《Calculus of Variations and Partial Differential Equations》2004,20(1):65-91
We study the limit behaviour of some nonlinear monotone equations, such as:
, in a domain
which is thin in some directions (e.g.
is a plate or a thin cylinder). After rescaling to a fixed domain
, the above equation is transformed into:
, with convenient operators
and
. Assuming that
and the inverse of
have particular forms and satisfy suitable compensated compactness assumptions, we prove a closure result, that is we prove that the limit problem has the same form. This applies in particular to the limit behaviour of nonlinear monotone equations in laminated plates.Received: 16 October 2002, Accepted: 12 June 2003, Published online: 22 September 2003Mathematics Subject Classification (2000):
35B27, 35B40, 74Q15 相似文献
7.
We study the regularizing effect of perimeter penalties for a problem of optimal compliance in two dimensions. In particular, we consider minimizers of
where
The sets
,
, and the force f are given. We show that if we consider only scalar valued u and constant
, or if we consider the elastic energy
, then
is
away from where
is pinned. In the scalar case, we also show that, for any
of class
,
is
. The proofs rely on a notion of weak outward curvature of
, which we can bound without considering properties of the minimizing fields, together with a bootstrap argument.Received: 5 March 2002, Accepted: 3 September 2002, Published online: 17 December 2002 相似文献
8.
With a map
,
, that belongs to the John Ball class
where n-1 < p < n and
one can associate a set valued map F whose values
are subsets of
describing the topological character of the singularity of f at
. verak conjectured that
, where S is the set of points at which f is not continuous and
is the Hausdorff measure. The purpose of our paper is to confirm this expectation.Received: 3 March 2003, Accepted: 15 April 2003, Published online: 1 July 2003Mathematics Subject Classification (2000):
74B20Piotr Hajasz: Hajasz was supported by KBN grant 2 PO3A 028 22 and Koskela by the Academy of Finland,SA-34082. Part of this research was done while Hajasz was at the Department of Mathematics of the University of Michigan. He wishes to thank UM for the support and hospitality. 相似文献
9.
Yavdat Il’yasov Thomas Runst 《Calculus of Variations and Partial Differential Equations》2005,22(1):101-127
This paper concerns with a family of inhomogeneous Neumann boundary value problems having indefinite nonlinearities which depend on a real parameter
. We discuss the existence and the multiplicity of positive solutions with respect to
. Developing the fibering method further, we can introduce a constructive concept of the calculation of certain nonlocal intervals
, the so-called sufficient intervals of the existence. Then we are able to prove some new results on the existence and the multiplicity of positive solutions
for
.Received: 22 December 2003, Accepted: 29 January 2004, Published online: 16 July 2004Mathematics Subject Classification (2000):
35J70, 35J65, 47H17 相似文献
10.
Finn and Kosmodemyanskii, Jr. gave an example of a domain
containing a disk
, and of a family of domains
converging to
as
, such that the heights u
t
of capillary surfaces in vertical tubes with the sections
in a gravity field g satisfy
for every
, but for which u
1< u
0 over
for all g > 0. In subsequent work, Finn and Lee characterized the most general convex
that leads to such a discontinuous transition when
is a disk. It has been suggested that the cause for this curious behavior is related to the fact that in all cases considered the boundaries of the
have a discontinuity in their curvatures, that is bounded below in magnitude. In the present note we present an alternative form of the example, in which the domains
are disks concentric to
. Thus, the limited smoothness in the original example of the convergence to
of the approxim
ating domains cannot be viewed as the root cause of the anomaly. The procedure presented here leads to explicit bounds, which were not available in the earlier forms of the example.Received: 3 September 2002, Accepted: 17 February 2003, Published online: 1 July 2003Mathematics Subject Classification:
76B45, 53A10, 49Q10 相似文献
11.
We establish existence of nodal solutions to the pure critical exponent problem
in
u = 0 on
where
a bounded smooth domain which is invariant under an orthogonal involution of
We extend previous results for positive solutions due to Coron, Dancer, Ding, and Passaseo to existence and multiplicity results for solutions which change sign exactly once.Received: 4 April 2003, Accepted: 26 August 2003, Published online: 24 November 2003Mathematics Subject Classification (2000):
35J65, 35J20Research partially supported by PAPIIT, UNAM, under grant IN110902-3. 相似文献
12.
We consider the following singularly perturbed semilinear elliptic problem:
where
is a bounded domain in R
N
with smooth boundary
,
is a small constant and f is some superlinear but subcritical nonlinearity. Associated with (I) is the energy functional
defined by
where
. Ni and Takagi ([29, 30]) proved that for a single boundary spike solution
, the following asymptotic expansion holds:
where c
1 > 0 is a generic constant,
is the unique local maximum point of
and
is the boundary mean curvature function at
. In this paper, we obtain a higher-order expansion of
where c
2, c
3 are generic constants and
is the scalar curvature at
. In particular c
3 > 0. Some applications of this expansion are given.Received: 14 January 2003, Accepted: 28 July 2003, Published online: 15 October 2003Mathematics Subject Classification (2000):
Primary 35B40, 35B45; Secondary 35J25 相似文献
13.
A sharp attainment result for nonconvex variational problems 总被引:2,自引:2,他引:0
We consider the problem of minimizing autonomous, multiple integrals like
where
is a continuous, possibly nonconvex function of the gradient variable
. Assuming that the bipolar function f** of f is affine as a function of the gradient
on each connected component of the sections of the detachment set
, we prove attainment for (
) under mild assumptions on f and f**. We present examples that show that the hypotheses on f and f** considered here for attainment are essentially sharp.Received: 12 May 2003, Accepted: 26 August 2003, Published online: 24 November 2003Mathematics Subject Classification (2000):
49J10, 49K10 相似文献
() |
14.
Min Ho Lee 《Monatshefte für Mathematik》2004,141(3):187-196
Let
be an equivariant holomorphic map of symmetric domains associated to a homomorphism
of semisimple algebraic groups defined over
. If
and
are torsion-free arithmetic subgroups with
, the map induces a morphism :
of arithmetic varieties and the rationality of is defined by using symmetries on
and
as well as the commensurability groups of and . An element
determines a conjugate equivariant holomorphic map
of which induces the conjugate morphism
of . We prove that is rational if is rational. 相似文献
15.
This is a follow-up of a paper of Bourgain, Brezis and Mironescu [2]. We study how the existence of the limit
for
continuous and
converging to
, is related to the weak regularity of
. This approach gives an alternative way of defining the Sobolev spaces W
1,p
. We also briefly discuss the
-convergence of (1) with respect to the
-topology.Received: 12 November 2002, Accepted: 7 January 2003, Published online: 22 September 2003Mathematics Subject Classification (2000):
46E35, 49J45Augusto C. Ponce: ponce@ann.jussieu.fr 相似文献
16.
Ovidiu Savin 《Calculus of Variations and Partial Differential Equations》2005,22(3):303-320
We consider the following obstacle problem for Monge-Ampere equation
and discuss the regularity of the free boundary
. We prove that
is
if f is bounded away from 0 and
, and it is C
1,1 if
.Received: 4 February 2003, Accepted: 3 March 2004, Published online: 16 July 2004 相似文献
17.
A Sobolev inequality with remainder term and critical equations on domains with topology for the polyharmonic operator 总被引:1,自引:0,他引:1
Thomas Bartsch Tobias Weth Michel Willem 《Calculus of Variations and Partial Differential Equations》2003,18(3):253-268
We prove a Sobolev inequality with remainder term for the imbedding
,
arbitrary, generalizing a corresponding result of Bianchi and Egnell for the case m = 1. We also show that the manifold of least energy solutions
of the equation
is a nondegenerate critical manifold for the corresponding variational integral. Finally we generalize the results of J. M. Coron on the existence of solutions of equations with critical exponent on domains with nontrivial topology to the biharmonic operator.Received: 21 March 2002, Accepted: 5 November 2002, Published online: 16 May 2003 相似文献
18.
Min-Chun Hong Changyou Wang 《Calculus of Variations and Partial Differential Equations》2005,23(4):425-450
For
and
, we show that any minimizing biharmonic map from
to Sk is smooth off a closed set whose Hausdorff dimension is at most n-5. When n = 5 and k = 4, for a parameter
we introduce a
-relaxed energy
of the Hessian energy for maps in
so that each minimizer
of
is also a biharmonic map. We also establish the existence and partial regularity of a minimizer of
for
.Received: 5 April 2004, Accepted: 19 October 2004, Published online: 10 December 2004 相似文献
19.
Manfred Stoll 《Monatshefte für Mathematik》2005,144(2):131-139
Let B denote the unit ball in n, n 1, and let and
denote the volume measure and gradient with respect to the Bergman metric on B. In the paper we consider the weighted Dirichlet spaces
,
, and weighted Bergman spaces
,
,
, of holomorphic functions f on B for which
and
respectively are finite, where
and
The main result of the paper is the following theorem.Theorem 1. Let f be holomorphic on B and
.(a) If
for some
, then
for all p,
, with
.(b) If
for some p,
, then
for all
with
. Combining Theorem 1 with previous results of the author we also obtain the following.Theorem 2. Suppose
is holomorphic in B. If
for some p,
, and
, then
. Conversely, if
for some p,
, then the series in * converges. 相似文献
20.
R. G. Novikov 《Selecta Mathematica, New Series》1997,3(2):245-302
We consider the Dirac-ZS-AKNS system (1) where (the space of functions with n derivatives in L
1), (2) We consider for (1) the transition matrix and, in addition, for the case of the Dirac system (i.e. for the selfadjoint case the scattering matrix We can divide main results of the present work into three parts. I. We show that the inverse scattering transform and the inverse Fourier transform give the same solution, up to smooth functions,
of the inverse scattering problem for (1). More preciseley, we show that, under condition (2) with , the following formulas are valid: (3) and, in addition, for the case of the Dirac system (4) where denotes the factor space. II. Using (3), (4), we give the characterization of the transition matrix and the scattering matrix for the case of the Dirac
system under condition (2) with
III. As applications of the results mentioned above, we show that 1) for any real-valued initial data , the Cauchy problem for the sh-Gordon equation has a unique solution such that and for any t > 0, 2) in addition, for , for such a solution the following formula is valid: where
denotes the space of functions locally integrable with n derivatives. We give also a review of preceding results. 相似文献