共查询到20条相似文献,搜索用时 31 毫秒
1.
Linghai ZHANG 《数学年刊B辑(英文版)》2008,29(2):179-198
Let u=u(x,t,uo)represent the global solution of the initial value problem for the one-dimensional fluid dynamics equation ut-εuxxt+δux+γHuxx+βuxxx+f(u)x=αuxx,u(x,0)=uo(x), whereα〉0,β〉0,γ〉0,δ〉0 andε〉0 are constants.This equation may be viewed as a one-dimensional reduction of n-dimensional incompressible Navier-Stokes equations. The nonlinear function satisfies the conditions f(0)=0,|f(u)|→∞as |u|→∞,and f∈C^1(R),and there exist the following limits Lo=lim sup/u→o f(u)/u^3 and L∞=lim sup/u→∞ f(u)/u^5 Suppose that the initial function u0∈L^I(R)∩H^2(R).By using energy estimates,Fourier transform,Plancherel's identity,upper limit estimate,lower limit estimate and the results of the linear problem vt-εv(xxt)+δvx+γHv(xx)+βv(xxx)=αv(xx),v(x,0)=vo(x), the author justifies the following limits(with sharp rates of decay) lim t→∞[(1+t)^(m+1/2)∫|uxm(x,t)|^2dx]=1/2π(π/2α)^(1/2)m!!/(4α)^m[∫R uo(x)dx]^2, if∫R uo(x)dx≠0, where 0!!=1,1!!=1 and m!!=1·3…(2m-3)…(2m-1).Moreover lim t→∞[(1+t)^(m+3/2)∫R|uxm(x,t)|^2dx]=1/2π(x/2α)^(1/2)(m+1)!!/(4α)^(m+1)[∫Rρo(x)dx]^2, if the initial function uo(x)=ρo′(x),for some functionρo∈C^1(R)∩L^1(R)and∫Rρo(x)dx≠0. 相似文献
2.
A graph G with p vertices and q edges, vertex set V(G) and edge set E(G), is said to be super vertex-graceful (in short SVG), if there exists a function pair (f, f
+) where f is a bijection from V(G) onto P, f
+ is a bijection from E(G) onto Q, f
+((u, v)) = f(u) + f(v) for any (u, v) ∈ E(G),
and
We determine here families of unicyclic graphs that are super vertex-graceful.
相似文献
3.
E. M. El-Kholy El-Said R. Lashin Salama N. Daoud 《Proceedings Mathematical Sciences》2007,117(3):293-300
In this paper we introduce a new type of folding called equi-Gaussian curvature folding of connected Riemannian 2-manifolds.
We prove that the composition and the cartesian product of such foldings is again an equi-Gaussian curvature folding. In case
of equi-Gaussian curvature foldings, f: M → P
n
, of an orientable surface M onto a polygon P
n
we prove that
and we generalize (iii) for #nT
2. 相似文献
((i)) |
((ii)) |
((iii)) |
4.
Let ϕ be an analytic self-map and u be a fixed analytic function on the open unit disk D in the complex plane ℂ. The weighted composition operator is defined by
Weighted composition operators from Bergman-type spaces into Bloch spaces and little Bloch spaces are characterized by function
theoretic properties of their inducing maps. 相似文献
5.
A. K. Tripathy 《Mathematica Slovaca》2008,58(2):221-240
Oscillatory and asymptotic behaviour of solutions of a class of nonlinear fourth order neutral difference equations of the
form
and
are studied under the assumption , for various ranges of p(n). Sufficient conditions are obtained for the existence of bounded positive solutions of (NH).
相似文献
6.
LetH
ibe a finite dimensional complex Hilbert space of dimensiond
i associated with a finite level quantum system Ai for i = 1, 2, ...,k. A subspaceS ⊂
is said to becompletely entangled if it has no non-zero product vector of the formu
1⊗u
2 ⊗ ... ⊗u
k with ui inH
i for each i. Using the methods of elementary linear algebra and the intersection theorem for projective varieties in basic
algebraic geometry we prove that
where ε is the collection of all completely entangled subspaces.
When
andk = 2 an explicit orthonormal basis of a maximal completely entangled subspace of
is given.
We also introduce a more delicate notion of aperfectly entangled subspace for a multipartite quantum system, construct an example using the theory of stabilizer quantum codes and pose a
problem. 相似文献
7.
A variant of Davenport’s constant 总被引:1,自引:1,他引:0
R. Thangadurai 《Proceedings Mathematical Sciences》2007,117(2):147-158
Let p be a prime number. Let G be a finite abelian p-group of exponent n (written additively) and A be a non-empty subset of ]n[≔ {1, 2,…, n} such that elements of A are incongruent modulo p and non-zero modulo p. Let k ≥ D(G/|A| be any integer where D(G) denotes the well-known Davenport’s constant. In this article, we prove that for any sequence g
1, g
2,…, g
k
(not necessarily distinct) in G, one can always extract a subsequence with 1 ≤ ℓ ≤ k such that
where a
j
∈ A for all j. We provide examples where this bound cannot be improved. Furthermore, for the cyclic groups, we prove some sharp results
in this direction. In the last section, we explore the relation between this problem and a similar problem with prescribed
length. The proof of Theorem 1 uses group-algebra techniques, while for the other theorems, we use elementary number theory
techniques. 相似文献
8.
Let H be a product of countably infinite number of copies of an uncountable Polish space X. Let Σξ
be the class of Borel sets of additive class ξ for the product of copies of the discrete topology on X (the Polish topology on X), and let . We prove in the Lévy-Solovay model that
for 1 ≤ ξ < ω
1. 相似文献
9.
Luisa Fattorusso 《Czechoslovak Mathematical Journal》2008,58(1):113-129
Let Ω be a bounded open subset of ℝ
n
, n > 2. In Ω we deduce the global differentiability result
for the solutions u ∈ H
1 (Ω, ℝ
n
) of the Dirichlet problem
with controlled growth and nonlinearity q = 2.
The result was obtained by first extending the interior differentiability result near the boundary and then proving the global
differentiability result making use of a covering procedure. 相似文献
10.
Annalisa Malusa Luigi Orsina 《Calculus of Variations and Partial Differential Equations》2006,27(2):179-202
We study the limit as n goes to +∞ of the renormalized solutions u
n
to the nonlinear elliptic problems
where Ω is a bounded open set of ℝ
N
, N≥ 2, and μ is a Radon measure with bounded variation in Ω. Under the assumption of G-convergence of the operators , defined for , to the operator , we shall prove that the sequence (u
n
) admits a subsequence converging almost everywhere in Ω to a function u which is a renormalized solution to the problem
相似文献
11.
Kamran Divaani-Aazar 《Proceedings Mathematical Sciences》2009,119(1):23-35
Let R be a (not necessarily local) Noetherian ring and M a finitely generated R-module of finite dimension d. Let be an ideal of R and denote the intersection of all prime ideals . It is shown that
where for an Artinian R-module A we put
A. As a consequence, it is proved that for all ideals of R, there are only finitely many non-isomorphic top local cohomology modules having the same support. In addition, we establish an analogue of the Lichtenbaum-Hartshorne vanishing theorem over rings
that need not be local. 相似文献
12.
A. K. Tripathy 《Mathematica Slovaca》2008,58(5):581-604
Oscillatory and asymptotic behaviour of solutions of a class of fourth order nonlinear neutral difference equations of the
form
and
are studied under the assumption < ∞, for different ranges of p(n). Sufficient conditions are obtained for the existence of positive bounded solutions of (E).
相似文献
13.
In this paper, sufficient conditions have been obtained under which every solution of
, oscillates or tends to zero or to ±∞ → ∞. Usually these conditions are stronger than
. An example is given to show that the condition (*) is not enough to arrive at the above conclusion. Existence of a positive
(or negative) solution of
is considered. 相似文献
14.
V. A. Galaktionov 《Computational Mathematics and Mathematical Physics》2008,48(10):1823-1856
The third-order nonlinear dispersion PDE, as the key model,
is studied. Two Riemann’s problems for (0.1) with the initial data S
∓(x) = ∓ sgn.x create shock (u(x, t) ≡ S
−(x)) and smooth rarefaction (for the data S
+) waves (see [16]). The concept of “δ-entropy” solutions and others are developed for establishing the existence and uniqueness
for (0.1) by using stable smooth δ-deformations of shock-type solutions. These are analogous to entropy theory for scalar
conservation laws such as u
t
+ uu
x
= 0, which were developed by Oleinik and Kruzhkov (in x ∊ ℝ
N
) in the 1950s–1960s. The Rosenau-Hyman K(2, 2) (compacton) equation
which has a special importance for applications, is studied. Compactons as compactly supported travelling wave solutions
are shown to be δ-entropy. Shock and rarefaction waves are discussed for other NDEs such as
.
This article was submitted by the author in English.
Dedicated to the memory of Professors O.A. Oleinik and S.N. Kruzhkov 相似文献
((0.1)) |
15.
In this paper we find a closed form of the solution for the factored inhomogeneous linear equation
Under the hypothesis A
1, A
2, …, A
n
are infinitesimal generators of mutually commuting strongly continuous semigroups of bounded linear operators on a Banach
space X. Here we do not assume that A
j
s are distinct and we offer the computational method to get explicit solutions of certain partial differential equations. 相似文献
16.
Rumen Tsanev Marinov 《Rendiconti del Circolo Matematico di Palermo》2009,58(1):11-27
In this article, we study an iterative procedure of the following form
, where f is a function and F is a set valued map acting from a Banach space X to a linear normed space Y, for solving generalized equations.
We show that this method is locally Q-linearly convergent to a solution x* of the generalized equation
if the set-valued map
is Aubin continuous at (0, x*) with a constant M for growth, f: X → Y is a function, whose Fréchet derivative is L-Lipschitz and A ∈ L(X,Y) is such that 2M∥Δf(x*) − A∥ < 1. We also study the stability of this method.
The research of this paper is partially supported by a Technical University of Varna internal research grant number 487/2008. 相似文献
17.
Ulrich Brehm 《Journal of Mathematical Sciences》2008,153(4):454-480
We show that under certain weak conditions on the module
R
M, every mapping
between the submodule lattices which preserves arbitrary joins and “disjointness” has a unique representation of the form
f(u) = 〈h[
S
B
R
×
R
U]〉 for all u ∈
, where
S
B
R
is some bimodule and h is an R-balanced mapping. Furthermore, f is a lattice homomorphism if and only if B
R
is flat and the induced S-module homomorphism
is monic. If
S
N also satisfies the same weak conditions, then f is a lattice isomorphism if and only if B
R
is a finitely generated projective generator, S ≅ End(B
R
) canonically, and
is an S-module isomorphism, i.e., every lattice isomorphism is induced by a Morita equivalence between R and S and a module isomorphism.
__________
Translated from Sovremennaya Matematika i Ee Prilozheniya (Contemporary Mathematics and Its Applications), Vol. 46, Algebra,
2007. 相似文献
18.
Chang Xing MIAO You Bin ZHU 《数学学报(英文版)》2008,24(1):17-26
The authors consider the well-posedness in energy space of the critical non-linear system of wave equations with Hamiltonian structure{utt-△u=-F1(|u|^2,|v|^2)u,utt-△u=-F2(|u|^2,|v|^2)u where there exists a function F(λ,μ) such that δF(λ,μ)/δλ=F1(λ,μ).δF(λ,μ)/δμ=F2(λ,μ) By showing that the energy and dilation identities hold for weak solution under some assumptions on the non-linearities, we prove the global well-posedness in energy space by a similar argument to that for global regularity as shown in "Shatah and Struwe's paper, Ann. of Math. 138, 503-518 (1993)". 相似文献
19.
In this work we prove a new strong convergence result of the regularized successive approximation method given by yn+1 = qnz0 + (1 - qn)T^nyn, n = 1, 2,…,where lim n→∞ qn = 0 and ∞∑n=1 qn=∞ for T a total asymptotically nonexpansive mapping, i.e., T is such that
││T^n x - T^n y││ ≤ x - y ││ + kn^(1)φ(││x - y││) + kn^(2),where kn^1 and kn^2 are real null convergent sequences and φ:R^+→R^+ is continuous such that φ(0)=0 and limt→∞φ(t)/t≤ C for a certain constant C 〉 0.
Among other features, our results essentially generalize existing results on strong convergence for T nonexpansive and asymptotically nonexpansive. The convergence and stability analysis is given for both self- and nonself-mappings. 相似文献
││T^n x - T^n y││ ≤ x - y ││ + kn^(1)φ(││x - y││) + kn^(2),where kn^1 and kn^2 are real null convergent sequences and φ:R^+→R^+ is continuous such that φ(0)=0 and limt→∞φ(t)/t≤ C for a certain constant C 〉 0.
Among other features, our results essentially generalize existing results on strong convergence for T nonexpansive and asymptotically nonexpansive. The convergence and stability analysis is given for both self- and nonself-mappings. 相似文献
20.
On sums of a prime and four prime squares in short intervals 总被引:1,自引:1,他引:0
In this paper, we prove that each sufficiently large integer N ≠1(mod 3) can be written as N=p+p1^2+p2^2+p3^2+p4^2, with
|p-N/5|≤U,|pj-√N/5|≤U,j=1,2,3,4,
where U=N^2/20+c and p,pj are primes. 相似文献
|p-N/5|≤U,|pj-√N/5|≤U,j=1,2,3,4,
where U=N^2/20+c and p,pj are primes. 相似文献