Let t=min{a1,a2,…,am−1} and b=a1+a2++am−1t. In this paper it is shown that whenever t=2,
R(a1,a2,…,am−1)=2b2+9b+8.
It is also shown that for all values of t,
R(a1,a2,…,am−1)tb2+(2t2+1)b+t3.
  相似文献   

14.
Double point self-transverse immersions of     
Mohammad A. Asadi-Golmankhaneh   《Topology and its Applications》2009,156(15):2452-2461
A self-transverse immersion of a smooth manifold M8k in has a double point self-intersection set which is the image of an immersion of a smooth four-dimensional manifold, cobordent to P4, P2×P2, P4+P2×P2 or a boundary. We will prove that for any value of k>1 the double point self-intersection set is a boundary. If k=1, then there exists an immersion of P2×P2×P2×P2 in with double point manifold boundary and odd number of triple points. In particular any immersion of oriented manifold in this dimension has double point manifold cobordant to a boundary.  相似文献   

15.
Global well-posedness and scattering for the defocusing -subcritical Hartree equation in     
Changxing Miao  Guixiang Xu  Lifeng Zhao   《Annales de l'Institut Henri Poincaré (C) Analyse Non Linéaire》2009,26(5):1831-1852
We prove the global well-posedness and scattering for the defocusing -subcritical (that is, 2<γ<3) Hartree equation with low regularity data in , d3. Precisely, we show that a unique and global solution exists for initial data in the Sobolev space with s>4(γ−2)/(3γ−4), which also scatters in both time directions. This improves the result in [M. Chae, S. Hong, J. Kim, C.W. Yang, Scattering theory below energy for a class of Hartree type equations, Comm. Partial Differential Equations 33 (2008) 321–348], where the global well-posedness was established for any s>max(1/2,4(γ−2)/(3γ−4)). The new ingredients in our proof are that we make use of an interaction Morawetz estimate for the smoothed out solution Iu, instead of an interaction Morawetz estimate for the solution u, and that we make careful analysis of the monotonicity property of the multiplier m(ξ)ξp. As a byproduct of our proof, we obtain that the Hs norm of the solution obeys the uniform-in-time bounds.  相似文献   

16.
Generalized rough approximations in     
Davide Ciucci  Tommaso Flaminio   《International Journal of Approximate Reasoning》2008,48(2):544
In this paper we will treat a generalization of inner and outer approximations of fuzzy sets, which we will call -inner and -outer approximations respectively ( being any finite set of rational numbers in [0,1]). In particular we will discuss the case of those fuzzy sets which are definable in the logic by means of step functions from the hypercube [0,1]k and taking value in an arbitrary (finite) subset of . Then, we will show that if a fuzzy set is definable as truth table of a formula of , then both its -inner and -outer approximation are definable as truth table of formulas of . Finally, we will introduce a generalization of abstract approximation spaces and compare our approach with the notion of fuzzy rough set.  相似文献   

17.
Construction of nonseparable dual -wavelet frames in     
Youfa Li  Shouzhi Yang   《Applied mathematics and computation》2009,215(6):2082-2094
Suppose and are two pairs of dual M-wavelet frames and N-wavelet frames in and , respectively, where M and N are s1×s1 and s2×s2 dilation matrices with a1(|det(M)|-1) and (2a2+1)(|det(N)|-1). Moreover, their mask symbols both satisfy mixed extension principle (MEP). Based on the mask symbols, a family of nonseparable dual Ω-wavelet frames in are constructed, where s=s1+s2, and with Θ and M-1Θ both being integer matrices. Then a convolution scheme for improving regularity of wavelet frames is given. From the nonseparable dual Ω-wavelet frames, nonseparable Ω-wavelet frames with high regularity can be constructed easily. We give an algorithm for constructing nonseparable dual symmetric or antisymmetric wavelet frames in . From the dual Ω-wavelet frames, nonseparable dual Ω-wavelet frames with symmetry can be obtained easily. In the end, two examples are given.  相似文献   

18.
Pointwise -convergence and -convergence in measure of sequences of functions     
Andrzej Komisarski   《Journal of Mathematical Analysis and Applications》2008,340(2):770-779
Let be an ideal. We say that a sequence of real numbers is -convergent to if for every neighborhood U of y the set of n's satisfying ynU is in . Basing upon this notion we define pointwise -convergence and -convergence in measure of sequences of measurable functions defined on a measure space with finite measure. We discuss the relationship between these two convergences. In particular we show that for a wide class of ideals including Erdős–Ulam ideals and summable ideals the pointwise -convergence implies the -convergence in measure. We also present examples of very regular ideals such that this implication does not hold.  相似文献   

19.
On the mean value of     
Huaning Liu  Xiaobeng Zhang 《Journal of Mathematical Analysis and Applications》2006,320(2):562-577
Let χ be the Dirichlet character modulo q3 and L(s,χ) denote the corresponding Dirichlet L-function. The mean value of is studied and a few asymptotic formulae are given. Hybrid mean value of , general Kloosterman sums and general quadratic Gauss sums are considered.  相似文献   

20.
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1.
We develop in this paper methods for studying the implicitization problem for a rational map defining a hypersurface in , based on computing the determinant of a graded strand of a Koszul complex. We show that the classical study of Macaulay resultants and Koszul complexes coincides, in this case, with the approach of approximation complexes and we study and give a geometric interpretation for the acyclicity conditions.Under suitable hypotheses, these techniques enable us to obtain the implicit equation, up to a power, and up to some extra factor. We give algebraic and geometric conditions for determining when the computed equation defines the scheme theoretic image of , and, what are the extra varieties that appear. We also give some applications to the problem of computing sparse discriminants.  相似文献   

2.
Let T be an ergodic automorphism of a probability space, f a bounded measurable function, . It is shown that the property that the probabilities μ(|Sn(f)|>n) are of order np roughly corresponds to the existence of an approximation in L of f by functions (coboundaries) ggT, gLp. Similarly, the probabilities μ(|Sn(f)|>n) are exponentially small iff f can be approximated by coboundaries ggT where g have finite exponential moments.

Résumé

Soit T un automorphisme ergodique d'un espace probabilisé, f une fonction bornée mesurable et . Une correspondance est établie entre l'existence de l'estimation des probabilités μ(|Sn(f)|>n) d'ordre np et l'existence de l'approximation dans L de la fonction f par des cobords ggTg est “presque” dans Lp. De manière similaire, les probabilités μ(|Sn(f)|>n) sont d'ordre ecn, pour un certain c>0, n=1,2… , si et seulement si f admet une approximation dans L par des cobords ggT avec g ayant des moments exponentiels.  相似文献   

3.
We give a sufficient condition for strictly positive definiteness in . The result is based on the question how sparse subsets of can be to guarantee linear independence of the exponentials.  相似文献   

4.
In [G. Marino, O. Polverino, R. Trombetti, On -linear sets of PG(3,q3) and semifields, J. Combin. Theory Ser. A 114 (5) (2007) 769–788] it has been proven that there exist six non-isotopic families (i=0,…,5) of semifields of order q6 with left nucleus and center , according to the different geometric configurations of the associated -linear sets. In this paper we first prove that any semifield of order q6 with left nucleus , right and middle nuclei and center is isotopic to a cyclic semifield. Then, we focus on the family by proving that it can be partitioned into three further non-isotopic families: , , and we show that any semifield of order q6 with left nucleus , right and middle nuclei and center belongs to the family .  相似文献   

5.
Compactness in     
This paper is concerned with compactness for some topologies on the collection of bounded linear operators on Banach spaces. New versions of the Eberlein–Šmulian theorem and Day's lemma in the collection are established. Also we obtain a partial solution of the dual problem for the quasi approximation property, that is, it is shown that for a Banach space X if X** is separable and X* has the quasi approximation property, then X has the quasi approximation property.  相似文献   

6.
We study PN and APN functions over the integers modulo n. We give some construction techniques based on Costas arrays, which allow us to construct APN permutations on where p is a prime. Although PN permutations do not exist, one set of our functions is very close to being a set of PN permutations.  相似文献   

7.
8.
Our aim in this paper is to investigate the global asymptotic stability of all positive solutions of the higher order nonlinear difference equation
where B, C and α, β, γ are positive, k {1, 2, 3, … }, and the initial conditions x−2k+1, … , x−1, x0 are positive real numbers. We show that the unique positive equilibrium of the equation is globally asymptotically stable and has some basins that depend on certain conditions posed on the coefficients. Our concentration is on invariant intervals, the character of semicycles, and the boundedness of the above mentioned equation. Our final comments are about informative examples.  相似文献   

9.
The solution of the linear operator equation:An-1X+An-2XB++AXBn-2+XBn-1=Y is given by if the spectra of A and B are in the sector {z:z≠0,-π/n<argz<π/n}.  相似文献   

10.
Paul D. Levy   《Journal of Algebra》2007,318(2):933-952
Let k be an algebraically closed field of characteristic 2. We prove that the restricted nilpotent commuting variety , that is the set of pairs of (n×n)-matrices (A,B) such that A2=B2=[A,B]=0, is equidimensional. can be identified with the ‘variety of n-dimensional modules’ for , or equivalently, for k[X,Y]/(X2,Y2). On the other hand, we provide an example showing that the restricted nilpotent commuting variety is not equidimensional for fields of characteristic >2. We also prove that if e2=0 then the set of elements of the centralizer of e whose square is zero is equidimensional. Finally, we express each irreducible component of as a direct sum of indecomposable components of varieties of -modules.  相似文献   

11.
The extension field where q is a prime divisor of (P−1), has a unique structure. This paper describes this unique structure and uses it to derive formulas relating the trace values for elements in . These formulas can be refined for certain elements to produce a formula for the trace.  相似文献   

12.
With the help of the concept of Kronecker map, an explicit solution for the matrix equation XAXF=C is established. This solution is neatly expressed by a symmetric operator matrix, a controllability matrix and an observability matrix. In addition, the matrix equation is also studied. An explicit solution for this matrix equation is also proposed by means of the real representation of a complex matrix. This solution is neatly expressed by a symmetric operator matrix, two controllability matrices and two observability matrices.  相似文献   

13.
For all integers m3 and all natural numbers a1,a2,…,am−1, let n=R(a1,a2,…,am−1) represent the least integer such that for every 2-coloring of the set {1,2,…,n} there exists a monochromatic solution to
a1x1+a2x2++am−1xm−1=xm.
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