共查询到20条相似文献,搜索用时 109 毫秒
1.
Mark Skandera 《Journal of Algebraic Combinatorics》2004,20(2):195-211
Let
I,I be the minor of a matrix which corresponds to row set I and column set I. We give a characterization of the inequalities of the form
I,I
K,K
J,J
L,L
which hold for all totally nonnegative matrices. This generalizes a recent result of Fallat, Gekhtman, and Johnson. 相似文献
2.
Let m
, 0 m+ in Kato's class. We investigate the spectral function s( + m) where s( + m) denotes the upper bound of the spectrum of the Schrödinger operator + m. In particular, we determine its derivative at 0. If m- is sufficiently large, we show that there exists a unique 1 > 0 such that s( + 1m) = 0. Under suitable conditions on m+ it follows that 0 is an eigenvalue of + 1m with positive eigenfunction. 相似文献
3.
Salvatore A. Marano 《Set-Valued Analysis》1996,4(3):287-300
Let be a bounded domain in n (n3) having a smooth boundary, let be an essentially bounded real-valued function defined on × h, and let be a continuous real-valued function defined on a given subset Y of Y h. In this paper, the existence of strong solutions u W
2,p (, h) W
o
1,p
(n/2<p<+) to the implicit elliptic equation (–u)=(x,u), with u=(u1, u2, ..., uh) and u=(u
1, u
2, ..., u
h), is established. The abstract framework where the problem is placed is that of set-valued analysis. 相似文献
4.
E. M. Matveev 《Mathematical Notes》1996,59(3):293-297
In this note we show that in the well-known Dobrowolski estimate lnM() (ln lnd/ lnd)3,d , where is a nonzero algebraic number of degreed that is not a root of unity andM() is its Mahler measure, the parameterd can be replaced by the quantity=d/()
1/d, where () is the modulus of the discriminant of. To this end, must satisfy the condition deg
p=deg for any primep.Translated fromMatematicheskie Zametki, Vol. 59, No. 3, pp. 415–420, March, 1996. 相似文献
5.
N. K. Bakirov 《Journal of Mathematical Sciences》1986,34(1):1403-1413
Let tn be the Bayesian estimator of the parameter constructed from independent observations in the case of infinite information and probability distribution density with some singularities. It is shown that under certain conditions on the behavior of the densities near their singularities, the normalizing factor (n) ensuring that n=(n) (tn-) has a nontriviallimiting distribution for n is regularly varying in Karamata's sense. The limiting distribution of n is determined.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 74, pp. 66–82, 1977.I would like to acknowledge the guidance of I. A. Ibragimov in the course of this research. 相似文献
6.
Let T be a homogeneous tree of homogeneity q+1. Let denote the boundary of T, consisting of all infinite geodesics b=[b
0,b
1,b
2,] beginning at the root, 0. For each b, 1, and a0 we define the approach region ,a
(b) to be the set of all vertices t such that, for some j, t is a descendant of b
j
and the geodesic distance of t to b
j
is at most (–1)j+a. If >1, we view these as tangential approach regions to b with degree of tangency . We consider potentials Gf on T for which the Riesz mass f satisfies the growth condition
T
f
p
(t)q
–|t|<, where p>1 and 0<<1, or p=1 and 0<1. For 11/, we show that Gf(s) has limit zero as s approaches a boundary point b within ,a
(b) except for a subset E of of -dimensional Hausdorff measure 0, where H
(E)=sup>0inf
i
q
–|t
i|:E a subset of the boundary points passing through t
i
for some i,|t
i
|>log
q
(1/). 相似文献
7.
Michael M. Vinogradov 《Acta Appl Math》1997,49(3):271-280
Let K R P be a tower of fields, N be a P-module, and : R N be a K-linear differential operator. The aim of this paper is to investigate whether the operator has an extension to P, i.e. if these exists a differential operator : P N such that |R = . The results of this paper were published in Russian in Mat. Zametki 30(2) (1981), 237–248. 相似文献
8.
R. de Meersman 《Numerische Mathematik》1968,11(3):257-263
Summary In this paper, the method of Garabedian is applied to finite difference equations derived from the elliptic diffusion operator –D + over rectangular and triangular nets. An example is given for which GARABEDIAN'S method yields a useless result. 相似文献
9.
René P. Sperb 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1980,31(6):740-753
In this paper the problem u+1=0 in ,u=0 on is considered. Here is a finite domain on a Riemannian manifold and the associated Laplace-Beltrami operator. By means of maximum principles isoperimetric bounds for the maximum ofu and the maximum of the absolute value of the gradient ofu, as well as some related bounds are derived.
Zusammenfassung Diese Arbeit behandelt das Problem u+1=0 in ,u=0 auf , wobei ein Gebiet auf einer zweidimensionalen Riemann'schen Mannigfaltigkeit ist, und der zugehörige Laplace-Beltrami Operator. Es werden isoperimetrische Schranken für das Maximum vonu und |u| aus gewissen Maximumsprinzipien hergeleitet, sowie einige verwandte Resultate.相似文献
10.
Philip W. Schaefer 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1978,29(4):693-697
Summary The uniqueness of the solution to two boundary value problems for the linear equation 3
u –a 2
u +b u –cu =F and to two boundary value problems for the quasilinear differential equation 2
u +w(u) =f are proved. The proofs follow as a consequence of maximum principles for a functional which is defined on solutions to the differential equation.
Zusammenfassung Die Eindeutigkeit der Lösung zweier Randwertaufgaben für die lineare Gleichung 3 u –a 2 u +b u –cu =F und zweier Randwertaufgaben für die quasilineare Differentialgleichung 2 u +w(u) =f wird bewiesen. Der Beweis folgt aus einem Maximumprinzip für ein Funktional, das für die Lösungen der Gleichung definiert ist.相似文献
11.
On a Problem of Karpilovsky 总被引:5,自引:0,他引:5
Let G be a finite elementary group. Let n (G) denote the nth power of the augmentation ideal (G) of the integral group ring G. In this paper, we give an explicit basis of the quotient group Qn(G) = n(G)/n+1 (G) and compute the order of Qn (G).2000 Mathematics Subject Classification: 16S34, 20C05 相似文献
12.
On the distribution of square-full and cube-full integers 总被引:1,自引:0,他引:1
Jie Wu 《Monatshefte für Mathematik》1998,126(4):353-367
LetN
r
(x) be the number ofr-full integers x and let
r
(x) be the error term in the asymptotic formula forN
r
(x). Under Riemann's hypothesis, we prove the estimates 2(x)x1/7+, 3(x)x97/804+(>0), which improve those of Cao and Nowak. We also investigate the distribution ofr-full andl-free numbers in short intervals (r=2,3). Our results sharpen Krätzel's estimates. 相似文献
13.
In this paper we prove the main step in establishing a limiting absorption principle for von Neumann-Wigner type Schrödinger Hamiltonians of the form –+csinb|x|/|x|+V(x), whereV(x) is a short range potential. The first fundamental step is to obtain a limiting absorption principal for the free operator –+csinb.|x|/|x|. The free operator is unitarily equivalent to a direct sum of ordinary differential operators. We obtain uniform estimates for the resolvents of these ordinary differential operators. by obtaining uniform estimates for the Weyl-Green kernels of these resolvents. In turn, these latter estimates require uniform estimates on the Wronskians of certain generalized eigen-solutions of these differential operators.This paper is dedicated to the memory of the late Professor Charles C. Conley. 相似文献
14.
Günter Schmidt 《Journal of Geometry》1997,60(1-2):146-159
In the pseudoeuclidean space1
E
3 a surface of degree 3 or 4 is calledDupin-cyclide if there exists a (pseudoeuclidean) torus such that a (pseudoeuclidean) spherical inversion maps upon . If the axis of is respectively space-like, isotropic or time-like is calledDupin-r-,-l- or-z-cyclide. ADupin-cyclide is the envelope of two families of spheres, the caustic surfaces of degenerate in caustic curves and the lines of curvature of constitute two (orthogonal) families of circles. 相似文献
15.
Blow-up rates for parabolic systems 总被引:7,自引:0,他引:7
Keng Deng 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1996,47(1):132-143
Let
n
be a bounded domain andB
R
be a ball in
n
of radiusR. We consider two parabolic systems: ut=u +f(), i= +g(u) in × (0,T) withu=v=0 on × (0,T) andu
t
=u, v
t
=v inB
r
× (0,T) withe/v=f (v), e/v=g(u) onB
R
× (0,T). Whenf(v) andg(u) are power law or exponential functions, we establish estimates on the blow-up rates for nonnegative solutions of the systems. 相似文献
16.
V. -B. K. Rogov 《Mathematical Notes》1970,7(2):152-157
The Beltrami-Laplace operator on a one-sheeted hyperboloid is hyperbolic. There is taken the set of functions bounded outside some neighborhood of two isotropic lines, intersecting at infinity. A necessary and sufficient condition is derived that a function of this set be an eigenfunction of the operator .Translated from Matematicheskie Zametki, Vol. 7, No. 2, pp. 255–263, February, 1970. 相似文献
17.
Catherine Bandle 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1975,26(3):357-359
Summary By means of Rellich's identity bounds for the spectrum of the nonlinear problem v+e
v=0 are derived and certain norms for the solutions are estimated.
Zusammenfassung Mit Hilfe einer Rellichschen Identität werden Schranken für das Spektrum des nichtlinearen Problems v+e v=0 angegeben. Ferner werden gewisse Normen für die Lösungen abgeschätzt.相似文献
18.
O. Axelsson 《BIT Numerical Mathematics》1984,24(4):413-424
Classical discretization error estimates for systems of ordinary differential equations contain a factor exp (Lt), whereL is the Lipschitz constant. For strongly monotone operators, however, one may prove that for a-method, 0<<1/2, the errors are bounded uniformly in time and with errorO(t)2, if=1/2–|O(t)|. This was done by this author (1977), for an operator in a reflexive Banach space and includes the case of systems of differential equations as a special case.In the present paper we restate this result as it may have been overlooked and consider also the monotone (inclusive of the conservative) and unbounded cases. We also discuss cases where the truncation errors are bounded by a constant independent of the stiffness of the problem. This extends previous results in [6] and [7]. Finally we discuss a boundary value technique in the context above.Dedicated to Germund Dahlquist: a stimulating teacher and researcher 相似文献
19.
Gert K. Pedersen 《Inventiones Mathematicae》1978,45(3):299-305
For each*-derivation of a separableC
*-algebraA and each >0 there is an essential idealI ofA and a self-adjoint multiplierx ofI such that (–ad(ix))|I< and x. 相似文献
20.
We prove that any graph with maximum degree sufficiently large, has a proper vertex colouring using +1 colours such that each colour class appears at most log8 times in the neighbourhood of any vertex. We also show that for 1, the minimum number of colours required to colour any such graph so that each vertex appears at most times in the neighbourhood of any vertex is (+1+1//), showing in particular that when =log/loglog, such a colouring cannot always be achieved with O() colours. We also provide a polynomial time algorithm to find such a colouring. This has applications to the total chromatic number of a graph.The second two authors were supported by NATO Collaborative Research Grant #CRG950235. 相似文献