ON MILIN-LEBDEV INEQUALITIES

Let \[\varphi (x) = \sum\limits_{k = 1}^\infty {{A_k}} {x^k},\Phi (x) = {e^{\varphi (x)}} = \sum\limits_{k = 1}^\infty {{D_k}} {x^k}\] \[\begin{gathered} \frac{1}{{{{(1 - x)}^\lambda }}} = \sum\limits_{k = 1}^\infty {{d_k}} (\lambda ){x^k} \hfill \ {\overline \Delta _n}(\lambda ) = {\lambda ^{2 - p}}\sum\limits_{k = 1}^\infty {{k^{p - 1}}} \mathop {|{A_k}|}\nolimits_{}^p - \sum\limits_{k = 1}^\infty {\frac{1}{k}} \hfill \\ \end{gathered} \] Milin-Lebedey proved that \[\sum\limits_{k = 0}^\infty {\frac{{|{D_k}{|^p}}}{{d_k^{p - 1}(\lambda )}}} \leqslant \exp \{ {\lambda ^{1 - p}}\sum\limits_{k = 1}^\infty {{k^{p - 1}}} |{A_k}{|^p}\} \] where p>l and \[\lambda \]>0. In this paper, we have proved the following theorems； Theorem 1. Let \[p \geqslant 1,\lambda > 0\] and \[F(x) = \sum\limits_{k = 0}^\infty {\frac{{|{D_k}{|^p}}}{{d_k^p(\lambda )}}} {x^p}\exp \{ - {\lambda ^{1 - p}}\sum\limits_{k = 1}^\infty {{k^{p - 1}}|{A_k}{|^p}{x^k}} \} (2)\] then F(x) is a decreasing function of x on [0, 1]. This theorem is stronger than the result (1). Theorem 2. Let \[p \geqslant 2,\lambda > 0\] and \[{{\bar Q}_n}(\lambda ) = \frac{1}{{n + 1}}\sum\limits_{k = 0}^n {\frac{{|{D_k}{|^p}}}{{d_k^p(\lambda )}}\exp } \{ - \frac{1}{{n + 1}}\sum\limits_{v = 1}^n {\overline {{\Delta _p}} } (\lambda )\} \] then \[{{\bar Q}_n}(\lambda )\] is a decreasing fimctLon of n(n=l, 2，...)In the case p=2 this is contained in the Miiin-Lebedev's result.     

ON MILIN-LEBDEV INEQUALITIES

Let \[\varphi (x) = \sum\limits_{k = 1}^\infty {{A_k}} {x^k},\Phi (x) = {e^{\varphi (x)}} = \sum\limits_{k = 1}^\infty {{D_k}} {x^k}\] \[\begin{gathered} \frac{1}{{{{(1 - x)}^\lambda }}} = \sum\limits_{k = 1}^\infty {{d_k}} (\lambda ){x^k} \hfill \ {\overline \Delta _n}(\lambda ) = {\lambda ^{2 - p}}\sum\limits_{k = 1}^\infty {{k^{p - 1}}} \mathop {|{A_k}|}\nolimits_{}^p - \sum\limits_{k = 1}^\infty {\frac{1}{k}} \hfill \\ \end{gathered} \] Milin-Lebedey proved that \[\sum\limits_{k = 0}^\infty {\frac{{|{D_k}{|^p}}}{{d_k^{p - 1}(\lambda )}}} \leqslant \exp \{ {\lambda ^{1 - p}}\sum\limits_{k = 1}^\infty {{k^{p - 1}}} |{A_k}{|^p}\} \] where p>l and \[\lambda \]>0. In this paper, we have proved the following theorems； Theorem 1. Let \[p \geqslant 1,\lambda > 0\] and \[F(x) = \sum\limits_{k = 0}^\infty {\frac{{|{D_k}{|^p}}}{{d_k^p(\lambda )}}} {x^p}\exp \{ - {\lambda ^{1 - p}}\sum\limits_{k = 1}^\infty {{k^{p - 1}}|{A_k}{|^p}{x^k}} \} (2)\] then F(x) is a decreasing function of x on [0, 1]. This theorem is stronger than the result (1). Theorem 2. Let \[p \geqslant 2,\lambda > 0\] and \[{{\bar Q}_n}(\lambda ) = \frac{1}{{n + 1}}\sum\limits_{k = 0}^n {\frac{{|{D_k}{|^p}}}{{d_k^p(\lambda )}}\exp } \{ - \frac{1}{{n + 1}}\sum\limits_{v = 1}^n {\overline {{\Delta _p}} } (\lambda )\} \] then \[{{\bar Q}_n}(\lambda )\] is a decreasing fimctLon of n(n=l, 2，...)In the case p=2 this is contained in the Miiin-Lebedev's result.     

一致L-Lipschitz的渐近伪压缩映象不动点的Ishikawa迭代逼近问题

在任意实的Banach空间中研究了用具误差的修正的Ishikawa与Mann迭代程序来逼近一致L-Lipschitz的渐近伪压缩映象不动点的强收敛性问题,在去掉条件$$\sum\limits_{n=0}^{\infty}\alpha_{n}^{2}<\infty, \q \sum\limits_{n=0}^{\infty }\gamma_{n}<\infty,\q \sum\limits_{n=0}^{\infty }\alpha_{n}(\beta_{n}+\delta_{n})<\infty,\q \sum\limits_{n=0}^{\infty}\alpha_{n}(k_{n}-1)<\infty$$之下,证明了相关文献的结果仍然成立.所得结果不但改进和推广了最近一些人的最新结果,而且也从根本上改进了定理的证明方法.     

MEAN APPROXIMATION OF A PERIODIC FUNCTION BY THE PARTIAL SUMS OF ITS FOURIER SERIES

Given a sequence of positive real numbers \[{\varepsilon _0},{\varepsilon _1},...,{\varepsilon _n},...\] which satisfy the conditions \[{\varepsilon _v} \to 0,{\varepsilon _v} - {\varepsilon _{v + 1}} \ge 0,{\varepsilon _v} - 2{\varepsilon _{v + 1}} + {\varepsilon _{v + 2}} \ge 0\] for v =0, 1, 2, ..., and a class L(s) of 2pi-periodic, L-integrable functions f(x) such that \[{E_n}{(f)_L} \le {\varepsilon _n}(n = 0,1,2,...)\], where \[{E_n}{(f)_L}\] is the best mean approximation of f(x) by trigonometrical polynomials of degree ≤n Let \[{S_n}(f)\] be the n-th partial sum of the Fourier series of f(x). It’s known that Oskolkov has proved \[\mathop {\sup }\limits_{f \in L(\varepsilon )} ||f - {S_n}{(f)_L}|| = \sum\limits_{v = n}^{2n} {\frac{{{\varepsilon _n}}}{{v - n + 1}}} \] where \[||f|{|_L} = \int_0^{2\pi } {|f(x)|} dx\] Oskolkov asked whether there is a single function \[{f_0}(x) \in L(s)\] for which the above relation is satisfied for all n, In this paper the following result is obtained. Theorem Let \[L(\varepsilon )\] be a class of 2pi-periodic, L-integrable functions as giyen above, then there exists a funotion \[{f_0}(x) \in L(\varepsilon )\] such that \[{{\tilde f}_0}(x) \in L(\varepsilon )\] and \[\begin{array}{l} \overline {\mathop {\lim }\limits_{n \to \infty } } \frac{{{{\left\| {{f_0} - {S_n}({f_0})} \right\|}_L}}}{{\sum\limits_{v = n}^{2n} {\frac{{{\varepsilon _n}}}{{v - n + 1}}} }} \ge C > 0\\overline {\mathop {\lim }\limits_{n \to \infty } } \frac{{{{\left\| {{{\tilde f}_0} - {S_n}({{\tilde f}_0})} \right\|}_L}}}{{\sum\limits_{v = n}^{2n} {\frac{{{\varepsilon _n}}}{{v - n + 1}}} }} \ge C > 0 \end{array}\] where C is an absolute constant. Some generalizations of the theorem are given.     

THE UNIFORM INTEGRABILITY OF A CLASS OF EXPONENTIAL MARTINGALES

若说\[(\Omega ,\mathcal{F},P)\]为完备概率空间，\[F = {({\mathcal{F}_t})_{t \in [a,b]}}\]为\[\mathcal{F}\]的递增子\[\sigma \]域族，且满足通常 条件，\[b \leqslant \infty \].又\[W = \{ {W_t},0 \leqslant t \leqslant b\} \]为关于F的Wiener过程，\[X = \{ {X_t},0 \leqslant t < b\} \]为 循序讨测过程，且 \[P\{ \int_0^b {X_t^2} dt < \infty \} = 1\]， 则可定义X关于W的Ito随机积分 \[{(X \cdot W)_t} = \int_0^t {{X_s}} d{W_s},0 \leqslant t \leqslant b\] 这时若记 \[{Z_t} = \exp \{ \int_0^t {{X_s}} d{W_s} - \frac{1}{2}\int_0^t {{X_s}^2} ds\} \] 它便是一个指数（局部）鞅.本文的目的在于证明当X为循序可测正态过程时，只要X关于W的积分存在，\[{\text{\{ }}{Z_t}0 \leqslant {\text{t < b\} }}\]总是一致可积的。 引理1若\[\{ {Z_t},0 \leqslant t < b\} \]为实可测正态过程且 \[\int_0^{\text{b}} {\left\| {{X_t}} \right\|} d{m_t} < \infty \] 其中\[\left\| {{X_t}} \right\| = {(E|{X_t}{|^2})^{1/2}}\],\[{m_t}\]为[0,b)上右连续递增函数，则X的几乎所有样本函数关于\[{m_t}\]可积，且其轨道积分 \[\tilde I = \int_0^{\text{b}} {{X_t}} d{m_t}\] 为正态分布随机变量. 引理2若\[X = \{ {X_t},0 \leqslant t < b\} \]为可测正态过程，其几乎所有样本函数关于右连续增函数\[{m_t}\]可积，即 \[P(\int_0^b {|{X_t}} |d{m_t} < \infty ) = 1\] 则按轨道积分 \[\tilde I = \int_0^{\text{b}} {{X_t}} d{m_t}\] 是正态分布随机变量. 引理3 若\[\{ {\xi _n},n \geqslant 1\} \]为正态分布随机变量序列，则 \[\sum\limits_{j = 1}^\infty {E{\xi _i}^2} \leqslant {[Eexp( - \frac{1}{2}\sum\limits_{j = 1}^\infty {{\xi _i}^2} )]^{ - 2}}\] 进而若\[\sum\limits_{j = 1}^\infty {E{\xi _i}^2} < 1\],则 \[E[exp(\frac{1}{2}\sum\limits_{j = 1}^\infty {{\xi _i}^2} )] \leqslant {(1 - \sum\limits_{j = 1}^\infty {E{\xi _i}^2} )^{ - \frac{1}{2}}}\] 引理4若\[{m_s}\]为[0, b)上右连续增函数，又\[X = \{ X_t^{(i)},0 \leqslant t < b,1 \leqslant i < \infty \} \]为正态 过程，则当\[P\{ \sum\limits_{i = 1}^\infty {\int_0^b {{{({X_t}^{(i)})}^2}d{m_t}} } < \infty \} = 1\]时必有 \[\sum\limits_{i = 1}^\infty {\int_0^b {{{({X_t}^{(i)})}^2}d{m_t}} } < \infty \} = 1\] 进而若;\[\sum\limits_{i = 1}^\infty {\int_0^b {{{({X_t}^{(i)})}^2}d{m_t}} } < 1\]，必有 \[Eexp(\frac{1}{2}\sum\limits_{i = 1}^\infty {\int_0^b {{{({X_t}^{(i)})}^2}d{m_s}} } ) \leqslant {(1 - \sum\limits_{j = 1}^\infty {E\int_0^b {{{({X_t}^{(i)})}^2}d{m_s}} } )^{ - \frac{1}{2}}}\] 定理 若\[W = (W_t^{(1)},...,W_t^{(n)},...)\]为一个具有无限个分量的过程，其分量都是连续 正态独立增量过程且满足 \[\begin{gathered} E\{ W_t^{(i)} - W_s^{(i)}\} = 0 \hfill \ E\{ (W_t^{(i)} - W_s^{(i)})(W_t^{(j)} - W_s^{(j)})\} = {\delta _{ij}}(m_t^{(i)} - m_s^{(i)}) \hfill \\ \end{gathered} \] 又\[\{ {f_t} = (f_t^{(1)},...,f_t^{(n)},...)\} \]为循序可测正态过程，若 \[P\{ \sum\limits_{i = 1}^\infty {\int_0^b {{{({f_t}^{(i)})}^2}dm_t^{(i)}} } < \infty \} = 1\] 则 \[{Z_t} = \exp \{ \sum\limits_{i = 1}^\infty {\int_0^b {{f_s}^{(i)}dW_s^{(i)} - \frac{1}{2}\int_0^t {{{({f_s}^{(i)})}^2}dm_s^{(i)}} } } \} ,0 \leqslant t < b\] 是一致可积鞅，特别有\[E{Z_0} = 1\] 利用上述结果及正态过程的Hida-Cramer分解，可以象[1]一样方便地讨论正态测 度的等价性问题并求出其Radon-Nikodym导数.     

The Estimation for the Multiple de la ValKe Poussin Square Remainders

Let Q_N={\bar x=(x_1,\cdots ,x_N)|-pi \leq x_i <\pi,i=1,\cdots,N} and X(Q_N) denote L(Q_N) and C(Q_N) , The square de la УаДбо Poussin sums of f\in X (Q_N) are defined by $V_n^n+l(f;\bar x)=\frac{1}{\pi ^N}\int _Q_N f(\bar x+\bar t)\prod\limits_{i = 1}^N {(\frac{1}{{l + 1}}} \sum\limits_{v = n}^{n + l} {{D_v}({t_i}))d\bar t(n,l = 0,1,2, \cdots )}$ where D_v(t) =sin(v+1/2)t/2sint/2, - The differences $R_n,l(f;\bar x)=f(\bar x)-V_n^n+l(f;\bar x)$ are called square remainders. We denote by E_k(f)_X the best approximation of the function f\in X(Q_N) by N-multiple trigonometric polynomials of order K. Theorem Let {\varepsilon _k}_k=0^\infty be a sequence such that \varepsilon _n \downarrow \infty(n\rightarrow \infty), the class $X(\varepsilon)={f\in X(Q_N)|E_k(f)_X \leq \varepsilon _k,k=0,1,2,\cdots}$ Then $C_N^'\sum\limits_{v=0}^n+l \frac {\varepsilon_v+nln^N-1(3+v/(l+1))}{v+l+1}\leq sup_{f\in X(\varepsilon)||R_n,l(f)||_X\leq C_N \sum\limits_{v=0}^{n+l}\frac {\varepsilon _v+nln^N-1(3+v/l+1)}{v+l+1}$ where C_N>C'_N>0 are constants depending only on N.     

关于广义{\Phi}-增生算子的最速下降法的收敛定理

设$E$为一致光滑Banach空间,$A:E\to E$为有界次连续广义${\it \Phi} $-增生算子满足:对任意$x_0\in E$,选取$m\ge 1$,使得$\| x_0 - x^* \| \le m$且$\mathop {\underline {\lim } }\limits_{r \to \infty } {\it \Phi} (r) > m\left\| {Ax_0 } \right\|$.设$\{C_n\}$为$[0,1]$中数列满足控制条件: i)$C_n\to 0\,(n\to\infty)$; ii)$\sum\limits_{n = 0}^\infty {C_n } = \infty $.设$\{x_n\}_{n\ge0}$由下式产生x_{n + 1} = x_n - C_n Ax_n ,\q n \ge 0, \eqno{(@)}$$则存在常数$a>0$,当$C_n < a$时,$\{x_n\}$强收敛于$A$的唯一零点$x^{*}$.     

On an Extension of Hadamard Inequalities for Convex Functions(in English)

设f是区间[a,b]上连续的凸函数，我们证明了Hadamard的不等式 $[f(\frac{{a + b}}{2}) \le \frac{1}{{b - a}}\int_a^b {f(x)dx \le \frac{{f(a) + f(b)}}{2}}$ 可以拓广成对[a,b]中任意n+1个点x_0,\cdots,x_n和正数组p_0,\cdots,p_n都成立的下列不等式 $f(\frac{\sum\limits_{i=0}^n p_ix_i}{\sum\limits_{i=0}^n p_i}) \leq |\Omega|^-1 \int_\Omega f(x(t))dt \leq \frac{\sum\limits _{i=0}^n {p_if(x_i)}}{\sum\limits_{i=0}^n p_i}$ 式中\Omega是一个包含于n维单位立方体的n维长方体，其重心的第i个坐标为$\sum\limits _{j=i}^n p_j /\sum\limits_{j=i-1}^n p_i$,|\Omega|为\Omega的体积，对\Omega中的任意点$t=(t_1,\cdots,t_n)$, $w(t)=x_0(1-t_1)+\sum\limits _{i=1}^{n-1} x_i(1-t_{i+1})\prod\limits_{j = 1}^i {{t_j}} +x_n \prod\limits _{j=1}^n t_j$ 不等式中两个等号分别成立的情形亦已被分离出来。 此不等式是著名的Jensen 不等式的精密化。     

Uniformly maldistributed sequences in a strict sense

It is shown that the following three limits

On the strong law of large numbers and additive functions

Let f(n) be a strongly additive complex-valued arithmetic function. Under mild conditions on f, we prove the following weighted strong law of large numbers: if X,X ₁,X ₂, … is any sequence of integrable i.i.d. random variables, then

A Mean-Value Theorem for Multiplicative Functions on the Set of Shifted Primes

Let f be a complex-valued multiplicative function, letp denote a prime and let π(x) be the number of primes not exceeding x. Further put $$m_p (f): = \mathop {\lim }\limits_{x \to \infty } \frac{1}{{\pi (x)}}\sum\limits_{p \leqslant x} {f(p + 1)} {\text{, }}M(f): = \mathop {\lim }\limits_{x \to \infty } \frac{1}{x}\sum\limits_{n \leqslant x} {f(n)}$$ and suppose that $$\mathop {\lim \sup }\limits_{x \to \infty } \frac{1}{x}\sum\limits_{n \leqslant x} {\left| {f\left( n \right)} \right|^2 } < \infty ,\sum\limits_{p \leqslant x} {\left| {f\left( n \right)} \right|^2 } \ll x\left( {\ln x} \right)^{ - \varrho } ,$$ with some \varrho > 0. For such functions we prove: If there is a Dirichlet character χ_d such that the mean-value M(f χ_d) exists and is different from zero,then the mean-value m_p(f) exists. If the mean-value M(f) exists, then the same is true for the mean-valuem_p(f) .     

On best approximation of functions of two variables

$\mathop {\lim \sup }\limits_{r \to \infty } \frac{{E_{n_i ,m_i } (f)_L }}{{[E_{n_i ,\infty } (f)_L + E_{\infty ,m_i } (f)_L ]ln\{ 2 + min(n_i ,m_i )\} }}\underset{\raise0.3em\hbox{$\mathop {\lim \sup }\limits_{r \to \infty } \frac{{E_{n_i ,m_i } (f)_L }}{{[E_{n_i ,\infty } (f)_L + E_{\infty ,m_i } (f)_L ]ln\{ 2 + min(n_i ,m_i )\} }}\underset{\raise0.3em\hbox{     

On the strong summation of Fourier series with variable exponents

Пустьf 2π-периодическ ая суммируемая функц ия, as _k (x) еë сумма Фурье порядк аk. В связи с известным ре зультатом Зигмунда о сильной суммируемости мы уст анавливаем, что если λn→∞, то сущес твует такая функцияf, что почти всюду $$\mathop {\lim \sup }\limits_{n \to \infty } \left\{ {\frac{1}{n}\mathop \sum \limits_{k = n + 1}^{2n} |s_k (x) - f(x)|^{\lambda _{2n} } } \right\}^{1/\lambda _{2n} } = \infty .$$ Отсюда, в частности, вы текает, что если λn?∞, т о существует такая фун кцияf, что почти всюду $$\mathop {\lim \sup }\limits_{n \to \infty } \left\{ {\frac{1}{n}\mathop \sum \limits_{k = 0}^n |s_k (x) - f(x)|^{\lambda _k } } \right\}^{1/\lambda _n } = \infty .$$ Пусть, далее, ω-модуль н епрерывности и $$H^\omega = \{ f:\parallel f(x + h) - f(x)\parallel _c \leqq K_f \omega (h)\} .$$ . Мы доказываем, что есл и λ _n ?∞, то необходимым и достаточным условие м для того, чтобы для всехf∈H ^ω выполнялос ь соотношение $$\mathop {\lim }\limits_{n \to \infty } \left\{ {\frac{1}{n}\mathop \sum \limits_{k = n + 1}^{2n} |s_k (x) - f(x)|^{\lambda _n } } \right\}^{1/\lambda _n } = 0(x \in [0;2\pi ])$$ является условие $$\omega \left( {\frac{1}{n}} \right) = o\left( {\frac{1}{{\log n}} + \frac{1}{{\lambda _n }}} \right).$$ Это же условие необхо димо и достаточно для того, чтобы выполнялось соотнош ение $$\mathop {\lim }\limits_{n \to \infty } \frac{1}{{n + 1}}\mathop \sum \limits_{k = 0}^n |s_k (x) - f(x)|^{\lambda _k } = 0(f \in H^\omega ,x \in [0;2\pi ]).$$      

THE ASYMPTOTIC BEHAVIOUR OF ANALYTIC FUNCTIONS

AIn this paper, the author obtains the following results:(1) If Taylor coeffiients of a function satisfy the conditions:(i),(ii),(iii)A_k=O(1/k) the for any h>0 the function φ(z)=exp{w(z)} satisfies the asymptotic equality the case h>1/2 was proved by Milin.(2) If f(z)=z α_2z~2 …∈S~* and,then for λ>1/2     

Bemerkungen über elementare Funktionen in nichtarchimedischen Banachalgebren

This paper deals with the behaviour of power series with coefficients in a non-archimedean valued field Ω for arguments in a non-archimedean Banachalgebra E/Ω. Beyond a trivial augmentation, the domain of convergence is extended in relation to Ω by certain elements b ∈ E for which \(\mathop {\lim }\limits_{n \to \infty } \left( {\frac{{||b^n ||}}{{||b||^n }}} \right) = 0\) . These elements are called pseudo-nilpotent and characterized by \(\mathop {\lim }\limits_{n \to \infty } (||b^n ||^{\frac{1}{n}} )< ||b||\) . The examples of exponential functions, logarithms and powers show the changes in relation to the methods and results in Ω caused by the extension of the domain of convergence and the absence of norm multiplicativity and invertibility in E. Finally the algebraic-topological structure of a part of the domain of convergence of the exponential function is presented.     

On multiplicative functions on consecutive integers

Let f and g be multiplicative functions of modulus 1. Assume that \( {\lim_{x \to \infty }}\frac{1}{x}\left| {\sum\nolimits_{n \leqslant x} {f(n)} } \right| = A > 0 \) and \( {\lim_{x \to \infty }}\frac{1}{x}\left| {\sum\nolimits_{n \leqslant x} {g(n)} } \right| = 0 \). We prove that, under these conditions,

$ \mathop {\lim }\limits_{x \to \infty } \frac{1}{x}\sum\limits_{n \leqslant x} {f(n)g(n + 1) = 0.}$

Concerning the Liouville function λ, we find an upper estimate for \( \frac{1}{x}\left| {\sum\limits_{n \leqslant x} {\lambda (n)\lambda (n + 1)} } \right| \) under the unproved hypothesis that L(s, χ) have Siegel zeros for an infinite sequence of L-functions.

     

Local limit theorem for the first crossing time of a fixed level by a random walk

Let X,X(1),X(2),... be independent identically distributed random variables with mean zero and a finite variance. Put S(n) = X(1) + ... + X(n), n = 1, 2,..., and define the Markov stopping time η _y = inf {n ≥ 1: S(n) ≥ y} of the first crossing a level y ≥ 0 by the random walk S(n), n = 1, 2,.... In the case $ \mathbb{E} $ \mathbb{E} |X|³ < ∞, the following relation was obtained in [8]: $ \mathbb{P}\left( {\eta _0 = n} \right) = \frac{1} {{n\sqrt n }}\left( {R + \nu _n + o\left( 1 \right)} \right) $ \mathbb{P}\left( {\eta _0 = n} \right) = \frac{1} {{n\sqrt n }}\left( {R + \nu _n + o\left( 1 \right)} \right) as n → ∞, where the constant R and the bounded sequence ν _n were calculated in an explicit form. Moreover, there were obtained necessary and sufficient conditions for the limit existence $ H\left( y \right): = \mathop {\lim }\limits_{n \to \infty } n^{{3 \mathord{\left/ {\vphantom {3 2}} \right. \kern-\nulldelimiterspace} 2}} \mathbb{P}\left( {\eta _y = n} \right) $ H\left( y \right): = \mathop {\lim }\limits_{n \to \infty } n^{{3 \mathord{\left/ {\vphantom {3 2}} \right. \kern-\nulldelimiterspace} 2}} \mathbb{P}\left( {\eta _y = n} \right) for every fixed y ≥ 0, and there was found a representation for H(y). The present paper was motivated by the following reason. In [8], the authors unfortunately did not cite papers [1, 5] where the above-mentioned relations were obtained under weaker restrictions. Namely, it was proved in [5] the existence of the limit $ \mathop {\lim }\limits_{n \to \infty } n^{{3 \mathord{\left/ {\vphantom {3 2}} \right. \kern-\nulldelimiterspace} 2}} \mathbb{P}\left( {\eta _y = n} \right) $ \mathop {\lim }\limits_{n \to \infty } n^{{3 \mathord{\left/ {\vphantom {3 2}} \right. \kern-\nulldelimiterspace} 2}} \mathbb{P}\left( {\eta _y = n} \right) for every fixed y ≥ 0 under the condition $ \mathbb{E} $ \mathbb{E} X ² < ∞ only; In [1], an explicit form of the limit $ \mathop {\lim }\limits_{n \to \infty } n^{{3 \mathord{\left/ {\vphantom {3 2}} \right. \kern-\nulldelimiterspace} 2}} \mathbb{P}\left( {\eta _0 = n} \right) $ \mathop {\lim }\limits_{n \to \infty } n^{{3 \mathord{\left/ {\vphantom {3 2}} \right. \kern-\nulldelimiterspace} 2}} \mathbb{P}\left( {\eta _0 = n} \right) was found under the same condition $ \mathbb{E} $ \mathbb{E} X ² < ∞ in the case when the summand X has an arithmetic distribution. In the present paper, we prove that the main assertion in [5] fails and we correct the original proof. It worth noting that this corrected version was formulated in [8] as a conjecture.     

Exponents for three-dimensional simultaneous Diophantine approximations

Let Θ = (θ ₁,θ ₂,θ ₃) ∈ ℝ³. Suppose that 1, θ ₁, θ ₂, θ ₃ are linearly independent over ℤ. For Diophantine exponents