Unified Limits and Large Deviation Principles for β-Laguerre Ensembles in Global Regime

Let(λ₁,...,λ_n) be β-Laguerre ensembles with ■parameters β,p,n and■ with for 1≤i≤n.In this paper,as β varies and satisfies lim_n→∞ log n/βn=0,we offer a modified Marchenko-Pastur,law or semicircle law as the weak limits for the sequence μ_n when lim_n→∞ n/p=γ∈(0,1] or lim_n→∞ n/p=0,respectively.This recovers some well-known results.Moreover,we give a full large deviation principle of μ_n with speed βn² and good rat...     

LARGE DEVIATIONS FOR TOP EIGENVALUES OF β-JACOBI ENSEMBLES AT SCALING TEMPERATURES

Let λ=(λ₁,…,λ_n) be β-Jacobi ensembles with parameters p₁,p₂,n and β,with β varying with n.Set■.Suppose that■ and 0 ≤σγ <1.We offer the large deviation for p₁+p₂/p₁■ λ_i when γ> 0 via the large deviation of the corresponding empirical measure and via a direct estimate,respectively,when γ=0.     

Weighted norm inequalities for the commutators of multilinear singular integral operators

In this paper, the authors consider the weighted estimates for the commutators of multilinear Calderón-Zygmund operators.By introducing an operator which shifts the commutation, and establishing the weighted estimates for this new operator, the authors prove that, if p₁ ∈ （1,∞）, p₂,…,p_m ∈(1,∞], p ∈ （0,∞） with 1/p =Σ1≤k≤ m 1/pk, then for any weight w, the commutators of m-linear Galderón-Zygmund operator are bounded from L^P1（Rⁿ,M_l（logL）^σw）× p2（Rn,M^w）×...×Lpm（Rn,Mw） to Lp（Rn,w）with σ to be a constant depending only on p₁ and the order of commutator     

Complexity of asymptotic behavior of solutions for the porous medium equation with absorption

In this paper we analyze the large time behavior of nonnegative solutions of the Cauchy problem of the porous medium equation with absorption u t-u m + γup = 0, where γ≥ 0, m 1 and p m + 2/N . We will show that if γ = 0 and 0 μ 2N/(N(m-1)+2), or γ 0 and 1/(p-1)μ2N/(N(m-1)+2), then for any nonnegative function φ in a nonnegative countable subset F of the Schwartz space S (R N ), there exists an initial-value u0 ∈C(RN) with lim x →∞ u 0 (x) = 0 such that φ is an ω-limit point of the rescaled solutions t μ/2 u(t β·, t), where β =[2-μ(m-1)]/4 .     

Stable direction recovery in single-index models with a diverging number of predictors

Large dimensional predictors are often introduced in regressions to attenuate the possible modeling bias. We consider the stable direction recovery in single-index models in which we solely assume the response Y is independent of the diverging dimensional predictors X when βτ 0 X is given, where β 0 is a p n × 1 vector, and p n →∞ as the sample size n →∞. We first explore sufficient conditions under which the least squares estimation β n0 recovers the direction β 0 consistently even when p n = o(√ n). To enhance the model interpretability by excluding irrelevant predictors in regressions, we suggest an e1-regularization algorithm with a quadratic constraint on magnitude of least squares residuals to search for a sparse estimation of β 0 . Not only can the solution β n of e1-regularization recover β 0 consistently, it also produces sufficiently sparse estimators which enable us to select "important" predictors to facilitate the model interpretation while maintaining the prediction accuracy. Further analysis by simulations and an application to the car price data suggest that our proposed estimation procedures have good finite-sample performance and are computationally efficient.     

Bounds for Average toward the Resonance Barrier for GL(3) × GL(2) Automorphic Forms

Let f be a fixed Maass form for SL₃(Z) with Fourier coefficients A_f(m,n).Let g be a Maass cusp form for SL₂(G) with Laplace eigenvalue (1/4)+k² and Fourier coefficient λ_g(n),or a holomorphic cusp form of even weight k.Denote by S_X(f×g,α,β) a smoothly weighted sum of A_f(1,n)λ_g(n)e(αn^β)for X 0 are fixed real numbers.The subject matter of the present paper is to prove ...     

Spectrum and Spectral Singularities of a Quadratic Pencil of a Schr?dinger Operator with Boundary Conditions Dependent on the Eigenparameter

In this paper, we consider the following quadratic pencil of Schr?dinger operators L(λ)generated in L²(R⁺) by the equation ■ with the boundary condition ■ where p(x) and q(x) are complex valued functions and α₀, α₁, β₀, β₁ are complex numbers with α₀β₁-α₁β₀≠0. It is proved that L(λ) has a finite number of eigenvalues and spectral singularities,and each of them is of a finite multiplicity...     

Moderate Deviations for Random Sums of Heavy-Tailed Random Variables

Let {Xn;n≥ 1} be a sequence of independent non-negative random variables with common distribution function F having extended regularly varying tail and finite mean μ = E（X1） and let {N（t）; t ≥0} be a random process taking non-negative integer values with finite mean λ（t） = E（N（t）） and independent of {Xn; n ≥1}. In this paper, asymptotic expressions of P（（X1 ＋… ＋XN（t）） -λ（t）μ 〉 x） uniformly for x ∈[γb（t）, ∞） are obtained, where γ〉 0 and b（t） can be taken to be a positive function with limt→∞ b（t）/λ（t） = 0.     

THE EXACT MEROMORPHIC SOLUTIONS OF SOME NONLINEAR DIFFERENTIAL EQUATIONS

We find the exact forms of meromorphic solutions of the nonlinear differential equations ■,n≥ 3,k≥1,where q,Q are nonzero polynomials,Q■ Const.,and p₁,p₂,α₁,α₂ are nonzero constants with α₁≠α₂.Compared with previous results on the equation p(z)f³+q(z)f"=-sinα(z) with polynomial coefficients,our results show that the coefficient of the term f~((k)) perturbed by multiplying an exponential function will affect the structur...     

Forced oscillation of second order differential equations with mixed nonlinearities

This article is concerned with the oscillation of the forced second order differential equation with mixed nonlinearities a(t) x ′ (t) γ′ + p 0 (t) x γ (g 0 (t)) + n i =1 p i (t) | x (g i (t)) | α i sgn x (g i (t)) = e(t), where γ is a quotient of odd positive integers, α i > 0, i = 1, 2, ··· , n, a, e, and p i ∈ C ([0, ∞ ) , R), a (t) > 0, gi : R → R are positive continuous functions on R with lim t →∞ g i (t) = ∞ , i = 0, 1, ··· , n. Our results generalize and improve the results in a recent article by Sun and Wong [29].     

Brake Orbits of a Reversible Even Hamiltonian System Near an Equilibrium

In this paper,we consider the brake orbits of a reversible even Hamiltonian system near an equilibrium.Let the Hamiltonian system(H S)x=J H(x)satisfies H(0)=0,H(0)=0,reversible and even conditions H(Nx)=H(x)and H(-x)=H(x)for all x∈R²ⁿ.Suppose the quadratic form Q(x)=1/2 is non-degenerate.Fixτ₀>0 and assume that R²ⁿ=E⊕F decomposes into linear subspaces E and F which are invariant under the flow associated to the linear system x=J H'(0)x and such that each solution of the above linear system in E isτ₀-periodic whereas no solution in F{0}isτ₀-periodic.Writeσ(τ₀)=σ_Q(τ₀)for the signature of Q|E.Ifσ(τ₀)≠=0,we prove that either there exists a sequence of brake orbits x_k→0 withτk-periodic on the hypersurface H^-1(0)whereτ_k→τ₀;or for eachλclose to 0 withλ_σ(τ₀)>0 the hypersurface H-1(λ)contains at least 1/2|σ(τ₀)|distinct brake orbits of the Hamiltonian system(HS)near 0 with periods nearτ₀.Such result for periodic solutions was proved by Bartsch in 1997.     

A new pinching theorem for complete self-shrinkers and its generalization

In this paper,we firstly verify that if M~n is an n-dimensional complete self-shrinker with polynomial volume growth in R~(n+1),and if the squared norm of the second fundamental form of M satisfies 0≤S-1≤1/18,then S≡1 and M is a round sphere or a cylinder.More generally,let M be a complete λ-hypersurface of codimension one with polynomial volume growth in R~(n+1) with λ≠0.Then we prove that there exists a positive constant γ,such that if |λ|≤γ and the squared norm of the second fundamental form of M satisfies0≤S-β_λ≤1/18,then S≡β_λ,λ 0 and M is a cylinder.Here β_λ=1/2(2+λ~2+|λ|(λ~2+4)~(1/2)).     

Strong Laws of Large Numbers for Double Sums of Banach Space Valued Random Elements

For a double array {V_(m,n), m ≥ 1, n ≥ 1} of independent, mean 0 random elements in a real separable Rademacher type p(1 ≤ p ≤ 2) Banach space and an increasing double array {b_(m,n), m ≥1, n ≥ 1} of positive constants, the limit law ■ and in L_p as m∨n→∞ is shown to hold if ■ This strong law of large numbers provides a complete characterization of Rademacher type p Banach spaces. Results of this form are also established when 0 p ≤ 1 where no independence or mean 0 conditions are placed on the random elements and without any geometric conditions placed on the underlying Banach space.     

On estimating the hidden periodicities in linear time series models

In this paper the tollowing modelX(n)=sum from j=1 to p α_je~(inλj)+ξ_nis considered,where p,λ_1,λ_2,…,λ_p,are constants α=(α_1,α_2,…,α_p) is a random vector and {ξ_n;n=0,±1,±2,…} is a wide-sense stationary sequence with zero means.In [4],theorem about thestrong consistent estimates of λ_1,λ_2.…,λ_p and α are proved under the assumption that α is a constantvector and p and δ are known constants such that0<δ<(?){λ_i-λ_j}.The main purpose of the present paper is to prove theorems on the strong consistent estimates ofparameters p,λ_1,λ_2,…,λ_p and random vector α without knowing p and δ.Numerical examples arealso given to illustrate our method of estimation.     

BOUND STATES FOR A STATIONARY NONLINEAR SCHRODINGER-POISSON SYSTEM WITH SIGN-CHANGING POTENTIAL IN R^3△

We study the following Schrodinger-Poisson system where （Pλ）{-△u＋ V（x）u＋λФ（x）u^p=x∈R^3,-△Ф=u^2,lim│x│→∞Ф（x） =0,u〉0,where λ≥0 is a parameter,1 〈 p 〈 ＋∞, V（x） and Q（x）=1 ,D.Ruiz[19] proved that（Pλ）with p∈ （2, 5） has always a positive radial solution, but （Pλ） with p E （1, 2] has solution only if λ 〉 0 small enough and no any nontrivial solution if λ≥1/4.By using sub-supersolution method,we prove that there exists λ0〉0 such that（Pλ）with p ∈（1＋∞）has alaways a bound state（H^1（R^3）solution for λ∈[0,λ0）and certain functions V（x）and Q（x）in L^∞（R^3）.Moreover,for every λ∈[0,λ0）,the solutions uλ of （Pλ）converges,along a subsequence,to a solution of （P0）in H^1 as λ→0     

ON A CLASS OF BESICOVITCHFUNCTIONS TO HAVE EXACT BOX DIMENSION： A NECESSARY AND SUFFICIENT CONDITION

This paper summarized recent achievements obtained by the authors about the box dimensions of the Besicovitch functions given byB(t) := ∞∑k=1 λs-2k sin(λkt),where 1 ＜ s ＜ 2, λk ＞ 0 tends to infinity as k →∞ and λk satisfies λk 1/λk ≥λ＞ 1. The results show thatlimk→∞ log λk 1/log λk = 1is a necessary and sufficient condition for Graph(B(t)) to have same upper and lower box dimensions.For the fractional Riemann-Liouville differential operator Du and the fractional integral operator D-v,the results show that if λ is sufficiently large, then a necessary and sufficient condition for box dimension of Graph(D-v(B)),0 ＜ v ＜ s - 1, to be s - v and box dimension of Graph(Du(B)),0 ＜ u ＜ 2 - s, to be s uis also lim k→∞logλk 1/log λk = 1.     

On a Refinement of Hardy-Hilbert's Inequality and Its Applications

§1. Introduction If p＞1, 1p+1q=1, an≥0, bn≥0, and 0＜∑∞n=1-λapn＜∞, 0＜∑∞n=1-λbqn＜∞ (λ=0,1), then∑∞m=1-λ∑∞n=1-λambnm+n+λ＜πsin(π/p)∑∞n=1-λapn1/p∑∞n=1-λbqn1/q,(1.1)where the constant π／sinπp is best possible for λ=0, or 1. For λ=0,1, (1.1) is named of HardyHilberts inequality, which is important in analysis and applications (see ［1］, Chapt. 9). On (1.1) for λ=0, by estimating a weight coefficient, Xu［2］ gave a refinement as∑∞m=1∑∞n=1ambnm+n＜∑∞n=…     

On approximation of smooth functions from null spaces of optimal linear differential operators with constant coefficients

For a real valued function f defined on a finite interval I we consider the problem of approximating f from null spaces of differential operators of the form Ln(ψ) = n ∑ k=0 akψ(k), where the constant coefficients ak ∈ R may be adapted to f . We prove that for each f ∈ C(n)(I), there is a selection of coefficients {a1, ,an} and a corresponding linear combination Sn( f ,t) = n ∑ k=1 bkeλkt of functions ψk(t) = eλkt in the nullity of L which satisfies the following Jackson’s type inequality: f (m) Sn(m )( f ,t) ∞≤ |an|2n|Im|1/1q/ep|λ|λn|n|I||nm1 Ln( f ) p, where |λn| = mka x|λk|, 0 ≤ m ≤ n 1, p,q ≥ 1, and 1p + q1 = 1. For the particular operator Mn(f) = f + 1/(2n) f(2n) the rate of approximation by the eigenvalues of Mn for non-periodic analytic functions on intervals of restricted length is established to be exponential. Applications in algorithms and numerical examples are discussed.     

NOTES ON ERDOS' CONJECTURE

Let Xn,n 1,be a sequence of independent random variables satisfying P(Xn = O) = 1 － P(Xn = an) = 1 － 1/pn,where an,n 1,is a sequence of real numbers,andpn isthenthprime,setFN(x)=P(N∑Xnn=1 x).The authors investigate a conjecture of Erdos in probabilistic number theory and show that in order for the sequence FN to be weakly convergent,it is both sufficient and necessary that there exist three numbers x0 and x1 ＜ x2 such that limsup(FN(x2) －FN(x1)) ＞ 0 holds,and Lo =N→∞ lim FN(x0) exists.Moreover,the authors point ont that they can also obtain the same N→∞ result in the weakened case of liminfP(Xn = 0) ＞ 0.n→∞     

THE VALUE DISTRIBUTION OF RANDOM ANALYTIC DIRICHLET SERIES OF NEUTRAL GROWTH (II)

This paper studies the value distribution of random analytic Dirichlet series f:(s) = ∞∑n=1 Zn(ω)e-sλn,where {Zn} is a sequence of independent random variables,n=1 with moments zero,such that infE{｜Zn｜}/E1/2{｜Zn｜2} σ ＞ 0.Suppose [h*(σ)]2 =∞∑n=1 E{｜Zn｜2}e-2σλn converges for any σ ＞ 0,and diverges for σ = 0.It is shown that if then with probability one,where β is a constant depending only upon the constant α.