共查询到20条相似文献,搜索用时 31 毫秒
1.
V. A. Slousch 《Journal of Mathematical Sciences》2003,115(2):2272-2278
Let A be a self-adjoint elliptic second-order differential operator, let (, ) be an inner gap in the spectrum of A, and let B(t) = A + tW
*
W, where W is a differential operator of higher order. Conditions are obtained under which the spectrum of the operator B(t) in the gap (, ) is either discrete, or does not accumulate to the right-hand boundary of the spectral gap, or is finite. The quantity N(, A, W, ), (, ), > 0 (the number of eigenvalues of the operator B(t) passing the point (, ) as t increases from 0 to ) is considered. Estimates of N(, A, W, ) are obtained. For the perturbation W
*
W of a special form, the asymptotics of N(, A, W, ) as + is given. Bibliography: 5 titles. 相似文献
2.
On the Coefficients of Some Subclasses of Univalent Functions 总被引:1,自引:0,他引:1
H. E. Darwish 《Southeast Asian Bulletin of Mathematics》2001,25(1):75-86
In this paper we consider the class Lc*(,,) consisting of analytic and univlent functions with negative coefficients and with fixed second coefficient. The object of the present paper is to show coefficient estimates, convex linear combinations, some distortion theoems and radii of starlikeness and convexity for f(z) in the class Lc*(,,). The results are generalized to families with finitely many fixed coefficients.AMS Subject Classification (1991) 30C45 相似文献
3.
H. D. Abramson 《BIT Numerical Mathematics》1970,10(1):1-5
Given a context-free grammarG with a cycle of productionsA
1 A
2
1,A
2 A
3
2, ...,A
m A
1
m, it is shown that there is a grammarG
1 in which the only left-recursive rules are of the formA
1 A
1
, andL(G
1)=L(G). Using this normalization it is then shown that a Boolean matrix used in the analysis phase of some syntax-directed translation schemes may be partitioned into rectangular and upper-triangular submatrices. 相似文献
4.
U. Goginava 《Analysis Mathematica》2000,26(3):209-226
In this paper we prove that if f C
(0, 1
N
) and the function f is of bounded partial variation, then the N-dimensional Walsh-Fourier series of the function f is uniformly (C,–) summable (1 +...+
N
< 1,
i
> 0, i = 1,...,N) in the sense of Pringsheim. If 1 +...+
N
= 1,
i
> 0, i = 1,2,...,N, then there exists a continuous function f
0 of bounded partial variation on [0, 1]
N
such that the Cesàro (C,–) means
m
–
(f0,Õ) of the N-dimensional Walsh-Fourier series of f
0 diverge over cubes. 相似文献
5.
In-Suk Wee 《Probability Theory and Related Fields》1990,85(4):469-488
Summary Let {X
t
} be a 1 process with stationary independent increments and its Lévy measurev be given byv{yy>x}=x
–L
1
(x), v{yy<–x}=x
–L
2
(x) whereL
1,L
2 are slowly varying at 0 and and 0<1. We construct two types of a nondecreasing functionh(t) depending on 0<<1 or =1 such that lim inf
a.s. ast 0 andt for some positive finite constantC.This research is partialy supported by a grant from Korea University 相似文献
6.
Živorad Tomovski 《Analysis Mathematica》2003,29(2):165-170
In this paper equivalent classes of the classes M'
and S'
p
r, p >1, 0,r {0,1,2,...,[]} defined by Sheng [5] are obtained. Then it is shown that the classes of Fourier coefficients S
p, S'
p(case r==0) and S
p(), p>1, defined by . V. Stanojevi, V. B. Stanojevi Sheng and the author of the present note are identical. As a corollary of this result, the L
1-estimate for cosine series, obtained in [10], is refined. 相似文献
7.
A. A. Klunnik 《Journal of Mathematical Sciences》1992,58(5):391-395
A general approach is proposed to the interpolation of x
-analytical functions of a complex variable with an arbitrary –,+[Basis
x
-analytical functions whose imaginary pan is a polynomial in x, and y are obtained in explicit form.Translated from Vychislitel'naya i Prikladnaya Matematika, No. 58, pp. 3–9, 1986. 相似文献
8.
Scott W. Weeks Graham C. Sander Ian G. Lisle Jean-Yves Parlange 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1994,45(6):841-853
When both the diffusivityD and fractional flow functionf have a power law dependence on the water content , i.e.D=D
o andf=+1, the nonlinear transport equation for radially symmetric two phase flow can, in certain circumstances, be reduced to a weakly coupled system of two first order nonlinear ordinary differential equations. Numerical solutions of these equations for a constant flux boundary conditionV
wo and comparison with experimental data are given. In particular, when the fluxV
wo and a are related byV
wo( + 1)/D
o=2, a new fully explicit analytical solution is found as (r, t)=(1 – r
2/4D
ot)1/ forr
2 < 4D
ot/ and (r, t)=0 forr
2 4D
ot/ We show that the existence of this exact soution is due to the presence of a Lagrangian symmetry. 相似文献
9.
Summary LetB=(B
t,t0) be a planar Brownian motion and let >0. For anyt0, the pointz=B
t is called a one-sided cone point with angle if there exist >0 and a wedgeW(,z) with vertexz and angle such thatB
sW(,z) for everys[t, t+]. Burdzy and Shimura have shown independently that one-sided cone points with angle exist when >/2 but not when 2. The present paper deals with the critical case =/2. We show that cone points with angle /2 do not exist. 相似文献
10.
JirÍ Adámek 《Applied Categorical Structures》1996,4(1):121-126
For a topological category over Set we prove that if a functor T: has a fixed cardinal (i.e. for each object K with card (UK)= we have card (UTK)), then T has a least fixed point, and if T has a successive pair of fixed cardinals and +, then T has a greatest fixed point. This extends results of Adámek and Koubek.Partial financial support of the Grant Agency of the Czech Republic under Grant No. 201/93/0950 is gratefully acknowledged. 相似文献
11.
Andrea Laforgia Martin E. Muldoon 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1988,39(2):267-271
Summary We show, among other things, that the positive zeros of a solution ofy
+x
y=0,y(0)=0 decrease to 1 as increases, 0.
To the memory of Milo Háik
This research was supported by grants from the Natural Sciences and Engineering Research Council (Canada) and Consiglio Nazionale delle Ricerche (Italy). Some of the work was done while the second-named author was visiting the Department of Mathematics, University of Torino. 相似文献
Sommario Si dimostra, tra l'altro, che gli zeri positivi d'una soiuzione diy +x y=0,y(0)=0 decrescono al limite 1, quando cresce, 0.
To the memory of Milo Háik
This research was supported by grants from the Natural Sciences and Engineering Research Council (Canada) and Consiglio Nazionale delle Ricerche (Italy). Some of the work was done while the second-named author was visiting the Department of Mathematics, University of Torino. 相似文献
12.
Toru Nakahara 《Monatshefte für Mathematik》1982,94(2):125-132
In this note we shall prove that there exist infinitely many cyclic biquadratic fieldsK whose integral bases are neither {1, , 2, } nor {1, , , 3) for any numbers , inK. Next, we shall construct infinitely many cyclic biquadratic fieldsK which have the index 1, but still have not the integral basis {1, , 2, 3) for every inK. Finally we shall give a class of biquadratic fields for a problem of Hasse concerning an integral basis. 相似文献
13.
Harold L. Putt 《Order》1984,1(2):173-185
In this note we discuss permutation groups (G, ) in which the set admits aG-invariant order. By aG-invariant partial order (G-partial order) we mean a partial order < of such that < implies g<g, for all and in andg inG. If the set admits aG-partial order which is a total order, then (G, ) is an O-permutation group (orderable permutation group).The main concern of this paper is the development of a foundation for partially ordered permutation groups analogous to the existing one for partially ordered groups, as found in Fuchs [2]. 相似文献
14.
Summary In each lattice point , of a rectangular net a numerical valueu
is given. A bicubical and twice continuously differentiable function is constructed interpolating the valuesu
. The method is known as «spline interpolation». 相似文献
15.
Let
n
be n-dimensional Euclidean space, and let : [0, L]
n
and : [0, L]
n
be closed rectifiable arcs in
n
of the same total length L which are parametrized via their arc length. is said to be a chord-stretched version of if for each 0s tL, |(t)–(s)| |(t)–(s)|. is said to be convex if is simple and if ([0, L]) is the frontier of some plane convex set. Individual work by Professors G. Choquet and G. T. Sallee demonstrated that if were simple then there existed a convex chord-stretched version of . This result led Professor Yang Lu to conjecture that if were convex and were a chord-stretched version of then and would be congruent, i.e. any chord-stretching map of a convex arc is an isometry. Professor Yang Lu has proved this conjecture in the case where and are C
2 curves. In this paper we prove the conjecture in general. 相似文献
16.
A measure for the denseness of sequences (an) mod 1, irrational, is the dispersion constantD() introduced byH. Niederreiter. In this paper the smallest accumulation point 1 of the set of theD() is determined and all those are explicitely given for whichD () < 1 holds. 相似文献
17.
Gonchar V. Yu. Tanatarov L. V. Chechkin A. V. 《Theoretical and Mathematical Physics》2002,131(1):582-594
The properties of stationary solutions of the one-dimensional fractional Einstein--Smoluchowski equation with a potential of the form x
2m+2, m=1,2,..., and of the Riesz spatial fractional derivative of order , 12, are studied analytically and numerically. We show that for 1<2, the stationary distribution functions have power-law asymptotic approximations decreasing as x
–(+2m+1) for large values of the argument. We also show that these distributions are bimodal. 相似文献
18.
Panagiotis Chatzidimou Joseph Hersch 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1984,35(4):470-477
Zusammenfassung Die Methode der inneren Parallelen von Makai und Pólya wird hier auf das Randwertproblem (3) angewendet. Die sich ergebenden Schranken (11) und (11) für das FunktionalQ() enthalten als Grenzfälle die von Pólya [9] erhaltenen Schranken (2) und (1) für die Torsionssteifigkeit (Fall=0) bzw. für den Grundton einer Membran (Fall
1.
Summary We apply here the method of interior parallels of Makai and Pólya to the boundary value problem (3). The resulting bounds (11) and (11) for the functionalQ() contain as limit cases the bounds (2) and (1) obtained by Pólya [9] for torsional rigidity (case=0) and for the lowest eigenfrequency of a membrane (case 1).相似文献
19.
Kevin O'Bryant 《Journal of Algebraic Combinatorics》2004,19(1):91-115
A Sturmian word is a map W :
{0,1} for which the set of {0, 1}-vectors F
n(W) {(W(i), W(i + 1),...,W(i + n – 1))
T
: i
} has cardinality exactly n + 1 for each positive integer n. Our main result is that the volume of the simplex whose n + 1 vertices are the n + 1 points in F
n(W) does not depend on W. Our proof of this motivates studying algebraic properties of the permutation ,n
(where is any irrational and n is any positive integer) that orders the fractional parts {}, {2},...,{n}, i.e., 0 < {,n
(1)} < {,n
(2)} < ··· < {,n
(n)} < 1. We give a formula for the sign of ,n
, and prove that for every irrational there are infinitely many n such that the order of ,n
(as an element of the symmetric group S
n) is less than n. 相似文献
20.
A. B. Aleksandrov 《Journal of Mathematical Sciences》1993,63(2):115-129
Let be an inner function, let C, ¦¦=1. Then the harmonic function [(+)]/(–)] is the Poisson integral of a singular measure
D. N. Clark's known theorem enables us to identify in a natural manner the space H2 H2 with the space L2
(
).Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova Akademii Nauk SSSR, Vol. 170, pp. 7–33, 1989. 相似文献