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1.
We prove that, for any given vertex ν* in a series-parallel graph G, its edge set can be partitioned into κ = min{κ′(G) + 1, δ(G)} subsets such that each subset covers all the vertices of G possibly except for ν*, where δ(G) is the minimum degree of G and κ′(G) is the edge-connectivity of G. In addition, we show that the results in this paper are best possible and a polynomial time algorithm can be obtained for actually finding such a partition by our proof.  相似文献   

2.
We consider the one-dimensional Schrödinger equation -f″ + qκf = Ef on the positive half-axis with the potential qκ(r) = (κ2 - 1/4)r-2. For each complex number ν, we construct a solution uνκ(E) of this equation that is analytic in κ in a complex neighborhood of the interval (-1, 1) and, in particular, at the “singular” point κ = 0. For -1 < κ < 1 and real ν, the solutions uνκ(E) determine a unitary eigenfunction expansion operator Uκ,ν: L2(0,∞) → L2(R, Vκ,ν), where Vκ,ν is a positive measure on R. We show that every self-adjoint realization of the formal differential expression -?r2 + qκ(r) for the Hamiltonian is diagonalized by the operator Uκ,ν for some ν ∈ R. Using suitable singular Titchmarsh–Weyl m-functions, we explicitly find the measures Vκ,ν and prove their continuity in κ and ν.  相似文献   

3.
It was conjectured by Á. Elbert in J. Comput. Appl. Math. 133 (2001) 65-83 that, given two consecutive real zeros of a Bessel function of order ν, jν,κ and jν,κ+1, the zero of the derivative between such two zeros jν,κ′ satisfies . We prove that this inequality holds for any Bessel function of any real order. In addition to these lower bounds, upper bounds are obtained. In this way we bracket the zeros of the derivative. It is discussed how similar relations can be obtained for other special functions which are solutions of a second order ODE; in particular, the case of the zeros of is considered.  相似文献   

4.
We define the function jνκ for all real κ > 0 as follows: for κ = 1, 2, … the jνκ denotes the kth positive zero of the Bessel function Jν(z) of first kind and for k ? 1 < κ < k, jνκ denotes the kth positive zero of the cylinder Bessel function Cν(z) = cos αJν(z) ? sin αYν(Z) with α = (k ? ν)π (see [2]), where Yν(x) is the Bessel function of second kind. We introduce the function ι(x) for x > ? 1,
l(x)=limκ→∞jκ,x,κκ
. and we prove, among other things, the inequality jνκ < κι(νκ). Moreover, we find the first three terms of the asymptotic expansion of ι(x), for large values of x and other properties of this function.  相似文献   

5.
Yor’s generalized meander is a temporally inhomogeneous modification of the 2(ν + 1)-dimensional Bessel process with ν  >   ? 1, in which the inhomogeneity is indexed by $\kappa \in [0, 2(\nu+1))$ . We introduce the noncolliding particle systems of the generalized meanders and prove that they are Pfaffian processes, in the sense that any multitime correlation function is given by a Pfaffian. In the infinite particle limit, we show that the elements of matrix kernels of the obtained infinite Pfaffian processes are generally expressed by the Riemann–Liouville differintegrals of functions comprising the Bessel functions J ν used in the fractional calculus, where orders of differintegration are determined by ν ? κ. As special cases of the two parameters (ν, κ), the present infinite systems include the quaternion determinantal processes studied by Forrester, Nagao and Honner and by Nagao, which exhibit the temporal transitions between the universality classes of random matrix theory.  相似文献   

6.
This paper examines how close the chordal SLE κ curve gets to the real line asymptotically far away from its starting point. In particular, when κ ? (0, 4), it is shown that if β > β κ  := 1/(8/κ ? 2), then the intersection of the SLE κ curve with the graph of the function y = x/(log x) β , x > e, is a.s. bounded, while it is a.s. unbounded if β = β κ . The critical SLE4 curve a.s. intersects the graph of $y=x^{{-({\rm log\,log\,x})}^{\alpha}}, x > e^e$ , x > e e , in an unbounded set if α ≤ 1, but not if α > 1. Under a very mild regularity assumption on the function y(x), we give a necessary and sufficient integrability condition for the intersection of the SLE κ path with the graph of y to be unbounded. When the intersection is bounded a.s., we provide an estimate for the probability that the SLE κ path hits the graph of y. We also prove that the Hausdorff dimension of the intersection set of the SLE κ curve and the real axis is 2 ? 8/κ when 4 < κ < 8.  相似文献   

7.
A finite element method scheme is constructed for boundary value problems with noncoordinated degeneration of input data and singularity of a solution. We look at a rate with which an approximate solution by the proposed finite element method converges toward an exact R ν -generalized solution in the weight set W 2,ν*+β 2+1/1 (Ω, δ), and establish estimates for the finite element approximation.  相似文献   

8.
Set-valued information systems are generalized models of single-valued information systems. The attribute set in the set-valued information system may evolve over time when new information arrives. Approximations of a concept by rough set theory need updating for knowledge discovery or other related tasks. Based on a matrix representation of rough set approximations, a basic vector H(X) is induced from the relation matrix. Four cut matrices of H(X), denoted by H[μ,ν](X), H(μ,ν](X), H[μ,ν)(X) and H(μ,ν)(X), are derived for the approximations, positive, boundary and negative regions intuitively. The variation of the relation matrix is discussed while the system varies over time. The incremental approaches for updating the relation matrix are proposed to update rough set approximations. The algorithms corresponding to the incremental approaches are presented. Extensive experiments on different data sets from UCI and user-defined data sets show that the proposed incremental approaches effectively reduce the computational time in comparison with the non-incremental approach.  相似文献   

9.
This paper deals with the relationship between the behavior of a real function ν(t) as t → + ∞ and the behavior of the Laplace transform F[ν](s) of the charge d ν(t), {fx906-1} near its singular point.  相似文献   

10.
By classical results of Hurewicz, Kechris and Saint-Raymond, an analytic subset of a Polish space X is covered by a Kσ subset of X if and only if it does not contain a closed-in-X subset homeomorphic to the Baire space ww. We consider the analogous statement (which we call the Hurewicz dichotomy) for ∑11j subsets of the generalized Baire space κκ for a given uncountable cardinal κ with κ = κ<κ. We show that the statement that this dichotomy holds at all uncountable regular cardinals is consistent with the axioms of ZFC together with GCH and large cardinal axioms. In contrast, we show that the dichotomy fails at all uncountable regular cardinals after we add a Cohen real to a model of GCH. We also discuss connections with some regularity properties, like the κ-perfect set property, the κ-Miller measurability, and the κ-Sacks measurability.  相似文献   

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