Notes on 2-parameter quantum groupsⅠ

A simpler definition for a class of 2-parameter quantum groups associated to semisimple Lie algebras is given in terms of Euler form.Their positive parts turn out to be 2-cocycle deformations of each other under some conditions.An operator realization of the positive part is given.     

Notes on 2-parameter quantum groups I

A simpler definition for a class of 2-parameter quantum groups associated to semisimple Lie algebras is given in terms of Euler form. Their positive parts turn out to be 2-cocycle deformations of each other under some conditions. An operator realization of the positive part is given. This work was partially supported by the National Natural Science Foundation of China (Grant Nos. 10431040, 10728102), the TRAPOYT, the FUDP and the Priority Academic Discipline from the MOE of China, the SRSTP from the STCSM, the Shanghai Priority Academic Discipline from the SMEC     

半次覆盖远离子群和有限群的可解性

本文定义了有限群的半次覆盖远离子群概念,研究了半次覆盖远离子群和有限群的可解性问题.利用某些半次覆盖远离子群刻划了有限群的可解性,得到了若所有的sylow子群(或极大子群)半次覆盖远离则群可解,推广了文献[6]中的结果.     

The Uniqueness of the Actions of Certain Branch Groups on Rooted Trees

It is proved that in many cases of interest the actions of groups on rooted trees can be recovered from the structure of the groups. The results apply to most of the groups introduced by the first author and to the Gupta–Sidki groups; they are proved in the wider context of branch groups satisfying two natural conditions.     

The order of elements in Sylow p-subgroups of the symmetric group

Define a random variable ξ_n by choosing a conjugacy class C of the Sylow p-subgroup of S_pn by random, and let ξ_n be the logarithm of the order of an element in C. We show that ξ_n has bounded variance and mean order log n /log p +O(1), which differs greatly from the average order of elements chosen with equal probability. This revised version was published online in June 2006 with corrections to the Cover Date.     

9中心化子群的结构

记#Cent（G）为群G的所有互不相同的元素的中心化子个数．如果#Cent（G）=礼,则称G为n中心化子群．本文给出了9中心化子群的结构．     

弱次正规子群和有限群的可解性

如果群G有次正规子群K使HK⊿⊿G且H∩K⊿⊿G,那么子群H被称做群G的弱次正规子群.利用极大子群Sylow子群或Sylow子群正规化子的子群的弱次正规性得到了一些关于有限群的可解性结论.     

On the normality of the rings of Schubert varieties

We prove that the cone over a Schubert variety inG/P (P being a maximal parabolic subgroup of classical type) is normal by exhibiting a 2-regular sequence inR(w) (the homogeneous coordinate ring of the Schubert varietyX(w) inG/P under the canonical protective embeddingG/P ⊂→ (p (H° G/P,L)),L being the ample generator of (PicG/P), which vanishes on the singular locus ofX(w). We also prove the surjectivity ofH° (G/Q, L) H° (X(w), L), whereQ is a classical parabolic subgroup (not necessarily maximal) ofG andL is an ample line bundle onG/Q.     

有限群的$Phi$-$tau$-可补子群

假设$tau$是一个子群算子, $H$是有限群$G$的一个$p$-子群. 令 $bar{G}=G/H_{G}$且$bar{H}=H/H_{G}$, 如果$bar{G}$有一个次正规子群$bar{T}$ 和一个包含于$bar{H}$ 的$tau$-子群$bar{S}$满足$bar{G}=bar{H}bar{T}$且$bar{H}capbar{T}leq bar{S}Phi(bar{H})$, 就称$H$是$G$的一个$Phi$-$tau$- 可补子群. 文章通过讨论群$G$的准素数子群的$Phi$-$tau$-可补性给出了超循环嵌入和$p$-幂零性的一些新的特征.     

Kaehler流形上的Hamilton力学

利用力学原理、现在微分几何理论和高等微积分把Hamihon力学推广至Kaehler流形上，建立Kaehler流形上Hamihon力学，并得到Hamilton向量场、Hamihon方程等复的数学形式．     

Solitary Solvable Groups

A subgroup H of a group G is a solitary subgroup of G if G does not contain another isomorphic copy of H. Combining together the concepts of solitary subgroups and solvable groups, we define (normal) solitary solvable groups and (normal) strongly solitary solvable groups. We derive several results that hold for these groups and we discuss classes of groups that, under certain hypotheses, are (normal) solitary solvable and (normal) strongly solitary solvable. We also derive several results about p-groups that are solitary solvable.