弱鞅的极大值不等式及其应用

本文建立了弱鞅的一些极大值不等式,这些不等式推广和改进了Christofides在Maximal inequalities for demimartingale and a strong law of large numbers. Statist Probab Left,50：357-363（2000）中的结果．利用得到的极大值不等式,可以得到其它一些结果,例如弱鞅的Doob型极大值不等式、弱鞅和PA序列的强大数定律和强收敛速度．最后,还给出了弱半鞅一致可积性的一个等价条件．     

弱Hardy鞅空间与鞅的弱原子分解

定义了一些弱Hardy鞅空间和3种类型的弱原子. 它们与经典的H_p鞅论中的Hardy鞅空间和原子形成对应. 然后证明了弱Hardy鞅空间上的3个弱原子分解定理. 利用鞅的弱原子分解, 给出了弱Hardy鞅空间上的次线性算子有界的一个充分条件. 利用这个条件, 得到关于鞅的一系列弱H_p范数不等式和弱(p,p)型不等式, 以及各个弱Hardy鞅空间的连续嵌入关系. 这些不等式是经典的H_p鞅论中基本不等式的弱型对应.     

弱Hardy正规鞅空间与原子分解

本文证明了弱Hardy正规鞅空间wHp和wH^sp上的原子分解定理.利用鞅的原子分解给出了弱Hardy正规鞅空间上的次线性算子有界的一个充分条件.利用这个条件得到了关于正规鞅的一些弱Lp范数不等式和弱（p,p）型不等式.这些结果是经典Hp鞅论中一些重要结果的弱型对应.     

弱Orlicz鞅空间的极大不等式

本文研究了弱Orlicz鞅空间的双Φ-不等式．利用鞅的极大算子理论和弱Orlicz范数的特点,得到了弱Orlicz鞅空间极大算子的Doob不等式和强弱(Φ1,Φ2)-型不等式．     

Hilbert-值半鞅序列的弱收敛

本文在条件UT下研究了Hilbert-值半鞅序列到连续Hilbert-值半鞅的收敛性,并在弱收敛的条件下研究了形如X^n=∫oa^n(X^n.,s)dY^ns ∫ob^n(X^n.,s)dA^ns,X^no=O,任意n≥1随机微分方程的稳定性,其中Y^n和A^n分别为Hilbert-值半鞅和分量为增过程的Hilbert-值有限变差过程。     

可积鞅测度的弱收敛

本文引入了可积鞅测度弱收敛的概念，并给出了可积鞅测弱收敛的一系列条件。     

两指标弱鞅的原子分解

建立了两指标弱鞅Hardy空间w∑p和w(H)p的原子分解定理,证明了这些空间上次线性算子有界的充分条件.由此建立的一系列鞅不等式,表明了两指标弱鞅Hardy空间之间的连续嵌入关系.     

H-值半鞅测度的弱收敛

本文引进了H-值半鞅测度，研究了其基本性质和与之相联系的随机积分，本文还引入了H-值半鞅测度序列依分布弱收敛的概念，建立了H-值半鞅测度的极限定理，给出了H-值半鞅测度弱收敛的条件。     

弱Lp空间上的基本鞅不等式

本文证明了鞅的关于弱Lp拟范数的Doob型不等式,Burkholder-Gundy-Davis型不等式和Rosenthal型不等式.     

弱Orlicz鞅空间的原子分解

本文对于几种类型的弱Orlicz 鞅空间建立了强型和弱型的原子分解定理, 证明了这些空间上的次线性算子的有界性以及这些空间彼此的连续嵌入关系. 弱Orlicz 空间是一类拟Banach 空间, 有关结论扩展了现有的关于Orlicz 空间和弱型Lorentz 空间的相关结论.     

A historical note on the 3/2-approximation algorithm for the metric traveling salesman problem

One of the most fundamental results in combinatorial optimization is the polynomial-time 3/2-approximation algorithm for the metric traveling salesman problem. It was presented by Christofides in 1976 and is well known as “the Christofides algorithm”. Recently, some authors started calling it “Christofides-Serdyukov algorithm”, pointing out that it was published independently in the USSR in 1978. We provide some historic background on Serdyukov's findings and a translation of his article from Russian into English.     

Correction to “Properties of pseudoholomorphic curves in symplectisations I: Asymptotics”

In our paper [1] we derived the proposition 2.1 from Lemma 2.2 which is clearly false and our aim is to give a proof of the proposition. We take the opportunity to remove also a flaw in the proof of Lemma 3.3. The results of [1] remain unaffected.     

On the extent of the (non) quasi-analytic classes

The authors thank the referee for giving them a reference for Lemma 2.1.     

On consistency of bounding operations in deterministic global optimization

This technical comment refers to the discussion of strong consistency of several bounding procedures in Lemma 2.1 and Proposition 2.1 of Ref. 1. A necessary clarification is given of the notion of convergence _q in Lemma 2.1, and a derivation of Proposition 2.1 is presented that includes a new and simple consistency proof of the classical bounding by convex envelopes used in many branch-and-bound procedures.     

Erratum to: “Subnormal, permutable, and embedded subgroups in finite groups”

The original version of the article was published in Central European Journal of Mathematics, 2011, 9(4), 915–921, DOI: 10.2478/s11533-011-0029-8. Unfortunately, the original version of this article contains a mistake: Lemma 2.1 (2) is not true. We correct Lemma 2.2 (2) and Theorem 1.1 in our paper where this lemma was used.     

α混合序列下的核密度估计量的相合性

本文在α-混合序列下,讨论了核密度估计量的强相合性与一致强相合性,并给出其收敛速度.这些结论改进了Bosq(1998)中引理2.1和定理2.1所获得的相应结论.     

Maximal inequalities for demimartingales and their applications

In this paper, we establish some maximal inequalities for demimartingales which generalize and improve the results of Christofides. The maximal inequalities for demimartingales are used as key inequalities to establish other results including Doob’s type maximal inequality for demimartingales, strong laws of large numbers and growth rate for demimartingales and associated random variables. At last, we give an equivalent condition of uniform integrability for demisubmartingales.     

On a square haystack game

A haystack game is a hider-seeker zero-sum game of locating a needle in a haystack. Baston and Bostock have obtained partial solutions to this game for the case of a square haystack. This paper supplements their results, thus confirming their belief that a complete solution is difficult.The author would like to thank a referee for his helpful comments, in particular for suggesting Lemma 2.1 which has led to a more concise and transparent treatment of Section 2.     

On a contact 3-structure

A contact 3-structure consists of three contact metric structures which satisfy the relation (2.1). On a product manifold of the real line and a manifold with a contact 3-structure, we can construct three almost Hermitian structures satisfying the quaternionic identities. From this view point we discuss a contact 3-structure. Owing to Hitchin's well known Lemma concerning to hyperk?hler structure (Lemma H), we show that a contact 3-structure is necessarily a Sasakian 3-structure. Received: 26 August 1999; in final form: 2 May 2000 / Published online: 4 May 2001     

Barely Transitive Locally Nilpotent p-Groups

My paper [2], which appeared in the special issue dedicatedto the late Professor Brian Hartley, contained an error in Lemma2.2 as a result of overlooking the case that the exponents k_ion p. 359 may be divisible by arbitrary powers of p, which waspointed out by Professor H. Smith. In order to overcome thissituation all of Section 2, except Lemma 2.1, has been rewritten.However this does not cause any change in the rest of the paper.In particular the original assertions remain correct.