共查询到20条相似文献,搜索用时 62 毫秒
1.
In this paper we shall consider the critical elliptic
equation
where
and a(x)
is a real continuous, non
negative function, not identically zero. By using a local Pohozaev
identity, we show that problem (0.1) does not admit a
family of solutions
which blows-up and concentrates as
at some zero point x0 of a(x)
if the order of flatness of the function a(x) at x0 is
相似文献
2.
We consider the general degenerate parabolic equation:
We prove existence of Kruzkhov entropy solutions of the associated
Cauchy problem for bounded data where the flux function F
is supposed to be continuous. Uniqueness is established under some additional
assumptions on the modulus of continuity of F and
b. 相似文献
3.
Let X be a Banach space and let
A be a closed linear operator on
X. It is shown that the abstract Cauchy problem
enjoys maximal regularity in weighted
L
p
-spaces with weights
, where
,
if and only if it has the property of maximal
L
p
-regularity.
Moreover, it is also shown that the derivation operator
admits an
-calculus in weighted
L
p
-spaces.
Received: 26 February 2003 相似文献
4.
Let p be a prime,
a finite p-group,
any finite group with order divisible by p,
and
any action of
on
. We show that the cardinality of the set of all derivations
with respect to this action is a multiple of
p. This
generalises theorems of Frobenius and Hall.
Received: 16 June 2003 相似文献
5.
We study the existence of classical (non-collision) T-periodic
solutions of the Hamiltonian system
where
and
is a T-periodic function in t which has a
singularity at
like
Under suitable conditions on H, we prove that if
then (HS) possesses at least one
non-collision solution and if
then the generalized solution of (HS) obtained in [5] has at most
one time of collision in its period. 相似文献
6.
The N-heap Wythoffs game is a two-player impartial game with
N piles of tokens of sizes
Players take turns removing any number of tokens from a single pile, or removing
(a1,..., aN)
from all piles - ai tokens from the i-th pile,
providing that
where is the nim addition. The first player that cannot make a move loses. Denote all the
P-positions (i.e., losing positions) by
Two conjectures were proposed on the game by Fraenkel [7]. When
are fixed, i) there exists an integer N1
such that when
. ii) there exist integers N2
and _2 such that when
, the golden section.In this paper, we provide a sufficient condition for the conjectures to hold, and subsequently
prove them for the three-heap Wythoffs game with the first piles having up to 10 tokens.AMS Subject Classification: 91A46, 68R05. 相似文献
7.
Consider the Schrödinger operator
with a complex-valued
potential v of period
Let
and
be the eigenvalues of L that are close to
respectively, with periodic (for n even),
antiperiodic (for n odd), and Dirichelet
boundary conditions on [0,1], and let
be the diameter of the spectral
triangle with vertices
We prove the following statement: If
then v(x) is a Gevrey function, and moreover
相似文献
8.
Let
be the set of all coloured permutations on the symbols 1, 2, . . . , n
with colours 1, 2, . . . , r, which is the analogous of the
symmetric group when r = 1, and the hyperoctahedral
group when r = 2. Let
be a subset of d colours; we define
to be the set of all coloured permutations
.
We prove that the number of
-avoiding coloured permutations in
.
We then prove that for any
,
the number of coloured permutations in
which avoid all patterns in
except for and contain exactly once equals
.
Finally, for any
,
this number equals
.
These results generalize recent results due to Mansour, Mansour and West, and Simion.AMS Subject Classification: 05A05, 05A15. 相似文献
9.
A class of bounded operators on Sobolev spaces 总被引:2,自引:0,他引:2
We describe a class of nonlinear operators which are bounded on the
Sobolev spaces
, for
and 1 < p <
. As a corollary, we prove that the Hardy-Littlewood maximal operator is bounded on
, for
and 1 < p <
; this extends the result of J. Kinnunen [7], valid for s = 1.
Received: 5 December 2000 相似文献
10.
Let X = {1, . . . ,
n}, and let
be a family of subsets
of X. Given the size of
, at least how many pairs
of elements of
must be disjoint? In
this paper we give a lower bound for the number of disjoint
pairs in
. The bound we obtain is
essentially best possible. In particular, we give a new proof of
a result of Frankl and of Ahlswede, that if
satisfies
then
contains at least as
many disjoint pairs as X(r).The situation is rather different if we restrict our
attention to
: then we are asking for
the minimum number of edges spanned by a subset of the Kneser
graph of given size. We make a conjecture on this lower bound,
and disprove a related conjecture of Poljak and Tuza on the
largest bipartite subgraph of the Kneser graph.* Research partially supported by NSF grant
DMS-9971788 相似文献
11.
Marilyn Breen 《Aequationes Mathematicae》2004,67(3):263-275
Summary.
We establish the following Helly-type result for infinite families
of starshaped sets in
Define the function f on
{1, 2} by
f(1) = 4,
f(2) = 3.
Let
be a fixed positive number, and let
be a uniformly bounded family of compact sets
in the plane. For k = 1, 2, if every
f(k)
(not necessarily distinct) members of
intersect in a starshaped set whose
kernel contains a k-dimensional
neighborhood of radius
, then
is a starshaped set whose kernel is at least
k-dimensional.
The number f(k) is best in each case.
In addition, we present a few results concerning the dimension of
the kernel in an intersection of starshaped sets in
Some of these involve finite families of sets, while others
involve infinite families and make use of the Hausdorff metric. 相似文献
12.
Given two disjoint subsets T
1 and
T
2 of
nodes in an undirected 3-connected graph G = (V, E) with node set
V and arc set
E, where
and
are even numbers, we
show that V can be
partitioned into two sets V
1 and
V
2
such that the graphs induced by V
1 and
V
2 are
both connected and
holds for each
j = 1,2. Such a partition can
be found in
time. Our proof relies
on geometric arguments. We define a new type of convex
embedding of k-connected
graphs into real space R
k-1 and prove that for
k = 3 such an embedding
always exists.
1 A preliminary version
of this paper with title Bisecting Two Subsets in 3-Connected
Graphs appeared in the Proceedings of the 10th Annual
International Symposium on Algorithms and Computation, ISAAC
99, (A. Aggarwal, C. P. Rangan, eds.), Springer LNCS 1741,
425–434, 1999. 相似文献
14.
The purpose of the paper is to study properties of solutions of the Cauchy problem for the equation
under the assumption
.
General selfsimilar solutions are constructed. Moreover, for initial data with some decay at infinity, we determine
the leading term of the asymptotics of solutions in
which is described by either solutions of the linear heat equation or by particular selfsimilar solutions of the original equation. 相似文献
15.
A. P. Scheglova 《Journal of Mathematical Sciences》2005,128(5):3306-3333
We consider the boundary-value problem
where
and n is the unit outward normal. We show that there exist so many nonequivalent positive weak solutions as prescribed under certain conditions on q and R. We construct nonradial solutions for [(n + 1)/2] + 1 ⩽ p < n and some q. Bibliography: 18 titles.__________Translated from Problemy Matematicheskogo Analiza, No. 30, 2005, pp. 121–144. 相似文献
16.
17.
It is shown that an algebraic frame L is regular if
and only if its compact
elements are complemented. More generally, it is shown that each pseudocomplemented
element is regular if and only if each
, with c compact, is complemented.
With a mild assumption on L, each
, with c compact, is regular precisely
when
for any
two minimal primes p and q
of L. These results are then interpreted in various frames of
subobjects of lattice-ordered groups and f-rings. 相似文献
18.
For an l-graph
, the Turán number
is the maximum number of edges in an n-vertex l-graph
containing no copy of
. The limit
is known to exist [8]. The Ramsey–Turán density
is defined similarly to
except that we restrict to only those
with independence number o(n). A result of Erdős and Sós [3] states that
as long as for every edge E of
there is another edge E′of
for which |E∩E′|≥2. Therefore a natural question is whether there exists
for which
.
Another variant
proposed in [3] requires the stronger condition that every set of vertices of
of size at least εn (0<ε<1) has density bounded below by some threshold. By definition,
for every
. However, even
is not known for very many l-graphs
when l>2.
We prove the existence of a phenomenon similar to supersaturation for Turán problems for hypergraphs. As a consequence, we
construct, for each l≥3, infinitely many l-graphs
for which
.
We also prove that the 3-graph
with triples 12a, 12b, 12c, 13a, 13b, 13c, 23a, 23b, 23c, abc, satisfies
. The existence of a hypergraph
satisfying
was conjectured by Erdős and Sós [3], proved by Frankl and R?dl [6], and later by Sidorenko [14]. Our short proof is based
on different ideas and is simpler than these earlier proofs.
* Research supported in part by the National Science Foundation under grants DMS-9970325 and DMS-0400812, and an Alfred P.
Sloan Research Fellowship.
† Research supported in part by the National Science Foundation under grants DMS-0071261 and DMS-0300529. 相似文献
19.
In this note we prove that the Laplacian with generalized Wentzell boundary
conditions on an open bounded regular domain in
defined by
generates an analytic semigroup of angle
on
for every > 0 and
(for the definition of
cf. (1.3)).Received: 13 July 2002 相似文献
20.
Zhaoli Liu Zhi-Qiang Wang 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2005,56(4):609-629
We obtain the existence of infinitely many nodal solutions for the Schrödinger type equation on
with
Here,
The nonlinearity f is symmetric in the sense of being odd in u, and may involve a combination of concave and convex terms.Received: November 11, 2003; revised: December 12, 2004Supported by NSFC:10441003 相似文献