A Generalized Vandermonde Determinant

We prove two determinantal identities that generalize the Vandermondedeterminant identity . In the first of our identities the set {0, ..., m} indexing the rows and columns of thedeterminant is replaced by an arbitrary finite order ideal in the set ofsequences of nonnegative integers which are 0 except for a finite numberof components. In the second the index set is replaced by an arbitraryfinite order ideal in the set of all partitions.     

Reduced Words and Plane Partitions

Let w ₀ be the element of maximal length in thesymmetric group S _n , and let Red(w ₀) bethe set of all reduced words for w ₀. We prove the identity which generalizes Stanley's [20] formula forthe cardinality of Red(w ₀), and Macdonald's [11] formula .Our approach uses anobservation, based on a result by Wachs [21], that evaluation of certainspecializations of Schubert polynomials is essentially equivalent toenumeration of plane partitions whose parts are bounded from above. Thus,enumerative results for reduced words can be obtained from the correspondingstatements about plane partitions, and vice versa. In particular, identity(*) follows from Proctor's [14] formula for the number of planepartitions of a staircase shape, with bounded largest part.Similar results are obtained for other permutations and shapes;q-analogues are also given.     

Optimal recovery methods for the integral on classes of differentiable functions

Найдены методы восст ановления интеграла по информации $$I\left( f \right) = \left\{ {f^{(j)} \left( {x_i } \right)\left( {j = 0, ..., \gamma _i - 1; i = 1, ..., n; 1 \leqq \gamma _i \leqq r; \gamma _i + ... + \gamma _n \leqq N} \right.} \right\},$$ оптимальные на класс ахW _p ^r ,r=1,2,...; 1≦p≦∞. Это позволило, в частност и, получить наилучшие для классаW _p ^r квадратурные форму лы вида $$\mathop \smallint \limits_0^1 f\left( x \right)dx = \mathop \Sigma \limits_{i = 1}^n \mathop \Sigma \limits_{j = 1}^{\gamma _i - 1} a_{ij} f^{(j)} \left( {x_i } \right) + \mathop \Sigma \limits_{j = 1}^{[{r \mathord{\left/ {\vphantom {r 2}} \right. \kern-\nulldelimiterspace} 2}]} b_j f^{(2j - 1)} \left( 0 \right) + \mathop \Sigma \limits_{k = 1}^{[{r \mathord{\left/ {\vphantom {r 2}} \right. \kern-\nulldelimiterspace} 2}]} c_k f^{(2k - 1)} \left( 1 \right) + R\left( f \right)$$ И $$\mathop \smallint \limits_0^1 f\left( x \right)dx = af\left( 0 \right) + \mathop \Sigma \limits_{i = 1}^n \mathop \Sigma \limits_{j = 0}^{\gamma _i - 1} a_{ij} f^{(j)} \left( {x_i } \right) + bf\left( 1 \right) + \mathop \Sigma \limits_{j = 1}^{[{r \mathord{\left/ {\vphantom {r 2}} \right. \kern-\nulldelimiterspace} 2}]} b_j f^{(2j - 1)} \left( 0 \right) + \mathop \Sigma \limits_{k = 1}^{[{r \mathord{\left/ {\vphantom {r 2}} \right. \kern-\nulldelimiterspace} 2}]} c_k f^{(2k - 1)} \left( 1 \right) + R\left( f \right).$$      

Complete variable-length “fix-free” codes

A set of codewords isfix-free if it is both prefix-free and suffix-free: no codeword in the set is a prefix or a suffix of any other. A set of codewords {x ₁,x ₂,...,x _n } over at-letter alphabet is said to becomplete if it satisfies the Kraft inequality with equality, so that

The inequality of Ky Fan and related results

In this survey paper, we present refinements, extensions, and variants of the inequality

Estimating the diameter of one class of functions in L2

Let

Kolmogorov-type inequalities and the best formulas for numerical differentiation

For a certain class of complex-valued functionsf(x), ?∞ $$u_N = \mathop {\inf }\limits_{\parallel A\parallel \leqslant N_\parallel f^{(n)} \parallel _{L_2 \leqslant } 1} \parallel f^{(k)} - A(f)\parallel C$$ of a differential operator by linear operators A with the norm ∥A∥ _L2 ^C ≤N,N,>0. Using the value u_N, the smallest constant Q in the inequality $$\parallel f^{(k)} \parallel _Q \leqslant Q\parallel f\parallel _{L_2 }^\alpha \parallel f^{(n)} \parallel _{L_2 }^\beta $$ is found.     

Sharp Kolmogorov-Type Inequalities for Moduli of Continuity and Best Approximations by Trigonometric Polynomials and Splines

In what follows, $C$ is the space of -periodic continuous functions; P is a seminorm defined on C, shift-invariant, and majorized by the uniform norm; is the mth modulus of continuity of a function f with step h and calculated with respect to P; , ( ), ,

Saturation theorems for generalized Bernstein polynomials

In the present paper, we give the explicit formula of the principal part of n ∑ k=0 ([k]q -[n]qx)sxk n-k-1 ∏ m=0 (1-qmx) with respect to [n]q for any integer s and q ∈ (0,1]. And, using the expressions, we obtain saturation theorems for Bn(f,qn;x) approximating to f(x) ∈ C[0,1], 0 < qn ≤ 1, qn → 1.     

Whitney Interpolation Constants Bounded by 2 for k = 5, 6, 7

Let f C[0, 1], k = 5, 6, 7. We prove that if f(i/(k – 1)) = 0, i = 0, 1,..., k – 1, then      

Estimates for Sums of Coefficients of Dirichlet Series with Functional Equation

Suppose we have a Dirichlet series L(s) = _{n = 1} a _n n ^–s such that it, and its twists by Dirichlet characters have analytic continuation and a functional equation of a specific kind. Suppose also that the root numbers of the twists are equidistributed on the unit circle. The purpose of this note is to get an estimate for the quantity for a prime modulus p.We use a modification of the method of Chandrasekharan and Narasimhan and we use in an essential way a Rankin-Selberg type estimate for the average of |a _n|².     

A Limit Result for U-Statistics of Binary Variables

Define , where is a symmetric U-type statistic, H _k() is the Hermite polynomial of degree k, and {X, X _n, n1} are independent identically distributed binary random variables with Pr(X{–1, 1}})=1. We show that according as EX=0 or EX0, respectively.     

A new limit theorem for Gaussian stochastic processes possessing the Baxter property

Let(t) be a Gaussian stochastic process with zero mean and correlation functionR(t, s), and let . We obtain conditions for the weak convergence of the sequence of stochastic processes ,t [0, 1] and we find the form of the limiting distribution. As a corollary, in the stationary case we find the limiting distribution asn for .Translated fromTeoriya Sluchainykh Protsessov, Vol. 15, pp. 90–97, 1987.     

Sharp Constants in Inequalities for Intermediate Derivatives (the Gabushin Case)

We solve Tikhomirov's problem on the explicit computation of sharp constants in the Kolmogorov type inequalities

Characterization of Besov-Triebel-Lizorkin spaces via approximation by Whittaker's cardinal series and related unconditional Schauder bases

Let

Monotone empirical Bayes tests for some discrete nonexponential families

This paper deals with the empirical Bayes two-action problem of testingH ₀ : θ ≤ θ_o versusH ₁ : θ > θ_o using a linear error loss for some discrete nonexponential families having probability function either $\begin{gathered} f_1 (x|\theta ) = (x\alpha + 1 - \theta )\theta ^x /\prod\limits_{j = 0}^x {(j\alpha + 1)} \\ or \\ f_1 (x|\theta ) = \left[ {\theta \prod\limits_{j = 0}^{x - 1} {(j\alpha + 1 - \theta )} } \right]/\left[ {\prod\limits_{j = 0}^x {(j\alpha + 1)} } \right] \\ \end{gathered} $ Two empirical Bayes tests δ_n* and δ_n** are constructed. We have shown that both δ_n* and δ_n** are asymptotically optimal, and their regrets converge to zero at an exponential decay rate O(exp( -cn)) for some c > 0, wheren is the number of historical data available when the present decision problem is considered.     

Bijective proofs of shifted tableau and alternating sign matrix identities

We give a bijective proof of an identity relating primed shifted gl(n)-standard tableaux to the product of a gl(n) character in the form of a Schur function and . This result generalises a number of well-known results due to Robbins and Rumsey, Chapman, Tokuyama, Okada and Macdonald. An analogous result is then obtained in the case of primed shifted sp(2n)-standard tableaux which are bijectively related to the product of a t-deformed sp(2n) character and . All results are also interpreted in terms of alternating sign matrix (ASM) identities, including a result regarding subsets of ASMs specified by conditions on certain restricted column sums.     

A class of inequalities for non-negative sequences

В работе для неотрица тельных последовате льностей (...,a _?1 ⁱ ), aa ₀ ⁱ ),a ₁ ⁱ ), ...), удовлетв оряющих условию \(0< \mathop {\sup }\limits_k a_k^{(i)}< \infty\) (i=1,...,т), доказ а но неравенство (1) $$\begin{gathered} \mathop \sum \limits_{k = - \infty }^\infty \mathop {\sup }\limits_{k \leqq k_1 + \ldots + k_m \leqq k + l} (a_{k_1 }^{(1)} \ldots a_{k_m }^{(m)} ) \geqq \hfill \\ \geqq \mathop \prod \limits_{i = 1}^m (\mathop {\sup }\limits_{ - \infty< k< \infty } a_k^{(i)} )\left[ {\mathop \sum \limits_{i = 1}^m \frac{{\mathop \sum \limits_{k = - \infty }^\infty (a_k^{(i)} )^{p_i } }}{{(\mathop {\sup }\limits_{ - \infty< k< \infty } a_k^{(i)} )^{p_i } }} + l - m + 1} \right], \hfill \\ \end{gathered}$$ гдеl произвольное не отрицательное целое число, 1≦p ₁, ...,p _m ≦∞ и \(\mathop \sum \limits_{i = 1}^m p_i^{ - 1} = 1\) . Это неравенство явля ется обобщением и уто чнением неравенств А. Прекопа, Ш. Данча и Л. Лейндлера. Доказано также, что ес ли все последователь ности содержат только коне чное число ненулевых членов, то н еобходимым условием для равенства в (1) является существование такого числа α>0, чтоa _k( ⁱ )=а илиa _k( ⁱ )=0 для всехi=1,...,m;?∞<k<∞.     

Some approximation theorems for modified Bernstein-Durrmeyer operators

The modified Bernstein-Durrmeyer operators discussed in this paper are given byM_nf≡M_n(f,x)=(n+2)P_(n,k)∫_0~1p_n+1.k(t)f(t)dt,whereWe will show,for 0<α<1 and 1≤p≤∞