带双参数的a,b无限维李代数W(a,b)的性质

研究了带双参数的a,b的无限维W(a,b)型李代数,这类李代数是Virasoro李代数的推广.本文研究了这类李代数的两类子代数,一类子代数同构无中心的Virasoro李代数,另一类子代数是交换李子代数,并且是理想.研究了这类李代数同构和同态,证明了g不是单李代数.     

一类只有两个不同非零交换理想的无限维李代数

构造了一类无限维李代数,它是无中心的Virasoro李代数的推广,且只有两个不同的非零交换的理想.还研究了这类李代数的理想、中心和子代数.     

Virasoro李代数的子代数间的同构及生成元

证明了无中心Virasoro李代数的有限维子代数同构的充分必要条件,证明了两个元素di,dj作为生成元的充分必要条件,找出了几组互相同构的无限维真子代数,研究了他们的极大性,单性以及其它性质.     

一类W-代数的导子和自同构

讨论了一类W-代数,这类李代数包含无中心的广义Virasoro子代数.本文确定了这类李代数的导子和自同构.     

一些无限维完备李代数

本文讨论了无限维完备李代数的一些性质,由Virasoro代数,Kac-Moody代数构造了几类无限维完备李代数.同时给出了Kac-Moody代数及其广义抛物子代数的导子代数的刻划.证明了完备李代数的Loop扩张仍为完备李代数.     

一些无限维完备李代数

本文讨论了无限继完备李代数的一些性质,由Virasoro代数,Kac－Moody代数构造了几类无限维完备李代数．同时给出了Kac－Moody代数及其广义抛物子代数的导子代数的刻划．证明了完备李代数的Loop扩张仍为完备李代数。     

非阶化Virasoro代数和Virasoro超代数及其中间序列模

介绍非阶化Virasoro(超)代数的概念,给出非阶化Virasoro(超)代数的中间序列模,并对非阶化Virasoro代数的子代数(秩为1的非阶化Witt代数)的中间序列模进行分类．     

非有限阶化无中心Virasoro超代数的表示

介绍非有限阶化无中心Virasoro超代数的概念,并通过具体计算给出了非有限阶化无中心Virasoro超代数的一类中间序列模.     

Virasoro 代数的自同构和自同态

关于 Virasoro 代数的理论的研究,在许多数学和物理分支中起着重要的作用.例如,仿射李代数,统计力学和二维共形量子场理论等.本文研究了 Virasoro 代数的自同构和自同态以及它的三维单子代数.Virasoro 代数 Vir 是一个无限维复李代数,有基{c,d_n|n∈Z}以及交换关系     

李代数L(Z,f,δ)的特殊性质

研究一类特殊的无限维李代数．利用系数矩阵和极大项,证明了这类李代数是半单李代数且没有二维交换子代数．     

New algebraic structures from Hermitian one-matrix model

Virasoro constraint is the operator algebra version of one-loop equation for a Hermitian one-matrix model, and it plays an important role in solving the model. We construct the realization of the Virasoro constraint from the Conformal Field Theory (CFT) method. From multi-loop equations of the one-matrix model, we get a more general constraint. It can be expressed in terms of the operator algebras, which is the Virasoro subalgebra with extra parameters. In this sense, we named as generalized Virasoro constraint. We enlarge this algebra with central extension, this is a new kind of algebra, and the usual Virasoro algebra is its subalgebra. And we give a bosonic realization of its subalgebra.     

Classification of irreducible weight modules over higher rank Virasoro algebras

Let G be a rank n additive subgroup of C and Vir[G] the corresponding Virasoro algebra of rank n. In the present paper, irreducible weight modules with finite dimensional weight spaces over Vir[G] are completely determined. There are two different classes of them. One class consists of simple modules of intermediate series whose weight spaces are all 1-dimensional. The other is constructed by using intermediate series modules over a Virasoro subalgebra of rank n−1. The classification of such modules over the classical Virasoro algebra was obtained by O. Mathieu in 1992 using a completely different approach.     

Left-symmetric algebra structures on the twisted Heisenberg-Virasoro algebra

The compatible left-symmetric algebra structures on the twisted Heisenberg-Virasoro algebra with some natural grading conditions are completely determined. The results of the earlier work on left-symmetric algebra structures on the Virasoro algebra play an essential role in determining these compatible structures. As a corollary, any such left-symmetric algebra contains an infinite-dimensional nontrivial subalgebra that is also a submodule of the regular module.     

Left-symmetric algebra structures on the W-algebra W(2, 2)

We study the compatible left-symmetric algebra structures on the W-algebra W(2, 2) with some natural grading conditions. The results of earlier work on left-symmetric algebra structures on the Virasoro algebra play an essential role in determining these compatible structures. As a corollary, any such left-symmetric algebra contains an infinite-dimensional trivial subalgebra that is also a submodule of the regular module.     

Blocks and modules for Whittaker pairs

Inspired by recent activities on Whittaker modules over various (Lie) algebras, we describe a general framework for the study of Lie algebra modules locally finite over a subalgebra. As a special case, we obtain a very general set-up for the study of Whittaker modules, which includes, in particular, Lie algebras with triangular decomposition and simple Lie algebras of Cartan type. We describe some basic properties of Whittaker modules, including a block decomposition of the category of Whittaker modules and certain properties of simple Whittaker modules under some rather mild assumptions. We establish a connection between our general set-up and the general set-up of Harish-Chandra subalgebras in the sense of Drozd, Futorny and Ovsienko. For Lie algebras with triangular decomposition, we construct a family of simple Whittaker modules (roughly depending on the choice of a pair of weights in the dual of the Cartan subalgebra), describe their annihilators, and formulate several classification conjectures. In particular, we construct some new simple Whittaker modules for the Virasoro algebra. Finally, we construct a series of simple Whittaker modules for the Lie algebra of derivations of the polynomial algebra, and consider several finite-dimensional examples, where we study the category of Whittaker modules over solvable Lie algebras and their relation to Koszul algebras.     

ℤ/2ℤ Invariants of the free fermion algebra

By using quantum vertex operators we study the invariance of the rank n free-fermion vertex algebra under the action of the group ?∕2? and obtain its minimal generating set. When n = 1, it is well known that this subalgebra is isomorphic to the Virasoro vertex algebra with central charge 1∕2. In the n = 2 case we show that invariant subalgebra is isomorphic to a simple quotient of a certain W-algebra, which we explicitly construct. For n≥3, our approach leads to a rediscovery of the spinor representation of the a?ne vertex algebra associated to the Lie algebra 𝔰𝔬(n) of I. Frenkel.     

Search for high dimensional integrable models

The possible high dimensional integrable models are studied in three different aspects: (i) starting from a strong symmetry operator of a known (1+1) -dimensional integrable model, we can construct a type of (n+1)-dimensional integrable models, high dimensional breaking soliton equations; (ii) from every concrete realization of the generalized Virasoro algebra, we can get many high dimensional integrable models in the meaning that the models possess generalized Virasoro symmetry algebra; (iii) starting from the Schwartz equations which possess conformal invariance, we can also get various high dimensional integrable models in the meaning that they possess Painlevé property. Project supported by the National Natural Science Foundation of China and the Natural Science Foundation of Zhejiang Province.