A Characterization of The Twisted Heisenberg-Virasoro Vertex Operator Algebra

The twisted Heisenberg-Virasoro algebra is the universal central extension of the Lie algebra of differential operators on a circle of order at most one.In this paper,we first study the variety of semi-conformal vectors of the twisted Heisenberg-Virasoro vertex operator algebra,which is a finite set consisting of two nontrivial elements.Based on this property,we also show that the twisted Heisenberg-Virasoro vertex operator algebra is a tensor product of two vertex operator algebras.Moreover,associating to properties of semi-conformal vectors of the twisted Heisenberg-Virasoro vertex operator algebra,we charaterized twisted Heisenberg-Virasoro vertex operator algebras.This will be used to understand the classification problems of vertex operator algebras whose varieties of semi-conformal vectors are finite sets.

Realization of Vertex Operators of 7-Twisted Affine Lie Algebra ■[θ]

In this paper, we construct a new algebra structure 7-twisted atone Lie algebra sl（3,C）[θ] and study its vertex operator representations.

Higher Genus Characters for Vertex Operator Superalgebras on Sewn Riemann Surfaces

We review our recent results on computation of the higher genus characters for vertex operator superalgebras modules. The vertex operator formal parameters are associated to local parameters on Riemann surfaces formed in one of two schemes of (self- or tori- ) sewing of lower genus Riemann surfaces. For the free fermion vertex operator superalgebra we present a closed formula for the genus two continuous orbifold partition functions (in either sewings) in terms of an infinite dimensional determinant with entries arising from the original torus Szeg? kernel. This partition function is holomorphic in the sewing parameters on a given suitable domain and possesses natural modular properties. Several higher genus generalizations of classical (including Fay’s and Jacobi triple product) identities show up in a natural way in the vertex operator algebra approach.

A general mirror equivalence theorem for coset vertex operator algebras

We prove a general mirror duality theorem for a subalgebra U of a simple conformal vertex algebra A and its commutant V=ComA(U).Specifically,we assume that A≌■_(i∈I)U_(i)■V_(i) as a U■V-module,where the U-modules Uiare simple and distinct and are objects of a semisimple braided ribbon category of Umodules,and the V-modules Viare semisimple and contained in a(not necessarily rigid) braided tensor category of V-modules.We also assume U=ComA(V).Under these conditions,we construct a braid-reversed tensor equivalence τ:u_(A)→v_(A),where u_(A)is the semisimple category of U-modules with simple objects Ui,i∈I,and v_(A)is the category of V-modules whose objects are finite direct sums of Vi.In particular,the V-modules Viare simple and distinct,and v_(A)is a rigid tensor category.As an application,we find a rigid semisimple tensor subcategory of modules for the Virasoro algebra at central charge 13+6p+6p^(-1),p∈Z_(≥2), which is braided tensor equivalent to an abelian 3-cocycle twist of the category of finite-dimensional sl2-modules.Consequently,the Virasoro vertex operator algebra at central charge 13+6p+6p^(-1)is the PSL_(2)(C)-fixed-point subalgebra of a simple conformal vertex algebra w(-p),analogous to the realization of the Virasoro vertex operator algebra at central charge 13-6p-6p^(-1)as the PSL_(2)(C)-fixed-point subalgebra of the triplet algebra W(p).

Operator Product Formula for a Special Macdonald Function

In this paper, we construct two sets of vertex operators S+ and S? from a direct sum of two sets of Heisenberg algebras. Then by calculating the vacuum expectation value of some products of vertex operators, we get Macdonald function in special variables xi = t i-1 ( i = 0,1, 2,). Hence we obtain the operator product formula for a special Macdonald function Pλ (1,t,,tn-1;q,t ) when n is finite as well as when n goes to infinity.

Constructing tensor products of modules for C2-cofinite vertex operator superalgebras

For any C2-cofinite vertex product and the P（z）-tensor product finite length are proved to exist, which operator superalgebra V, the tensor of any two admissible V-modules of are shown to be isomorphic, and their constructions are given explicitly in this paper.

P-twisted affine Lie algebra and its realizations by twisted vertex operators

In this paper, we define a P-twisted affine Lie algebra, and construct its realizations by twisted vertex operators.

Extension of Vertex Operator Algebra VH4（e, 0）

We classify the irreducible restricted modules for the affine Nappi-Witten Lie algebra H4 with some natural conditions. It turns out that the representation theory of H4 is quite different from the theory of representations of Heisenberg algebras. We also study the extension of the vertex operator algebra VH4 （e, 0） by the even lattice L. We give the structure of the extension VH4 （e, 0） [L] and its irreducible modules via irreducible representations of VH4（e, 0） viewed as a vertex algebra.

The varieties of Heisenberg vertex operator algebras

For a vertex operator algebra V with conformal vector w, we consider a class of vertex operator subalgebras and their conformal vectors. They are called semi-conformal vertex operator subalgebras and semi- conformal vectors of （V, w）, respectively, and were used to study duality theory of vertex operator algebras via coset constructions. Using these objects attached to （V,w）, we shall understand the structure of the vertex operator algebra （V,w）. At first, we define the set Sc（V,w） of semi-conformal vectors of V, then we prove that Sc（V,w） is an aiYine algebraic variety with a partial ordering and an involution map. Corresponding to each semi-conformal vector, there is a unique maximal semi-conformal vertex operator subalgebra containing it. The properties of these subalgebras are invariants of vertex operator algebras. As an example, we describe the corresponding varieties of semi-conformal vectors for Heisenberg vertex operator algebras. As an application, we give two characterizations of Heisenberg vertex operator algebras using the properties of these varieties.

Bimodules associated to vertex operator superalgebras

Let V be a vertex operator superalgebra and m, n ∈ 1/2 ?+. We construct an A n (V)-A m (V)-bimodule A n,m (V) which characterizes the action of V from the level m subspace to level n subspace of an admissible V-module. We also construct the Verma type admissible V-module from an A m (V)-module by using bimodules

Coset vertex operator algebras and W-algebras of A-type

We give an explicit description for a weight three generator of the coset vertex operator algebra C_L_(sln)(l,0)L_(sln)(1,0)(L_(sln)(l+1,0),for n≥2, l≥1. Furthermore, we prove that the nommutant C_L_(sl3)(l,0)L_(sl3)(1,0)(L_(sl3)(l+1,0)) is isomorphic to the W-algebra W_(-3+(l+3)/(l+4))(sl_3), which confirms the conjecture for the sl_3 case that C_L_g(l,0)L_g(1,0)(L_g(l + 1,0)) is isomorphic to W_(-h+(l+h)/(l+h+1))(g) for simaly-laced Lie algebras g with its Coxeter number h for a positive integer l.

Representations of Code Vertex Operator Superalgebras

We study the representations of code vertex operator superalgebras resulting from a binary linear code which contains codewords of odd weight. We also show that there exists only one set of seven mutually orthogonal conformal vectors with central charge 1/2 in the Hamming code vertex operator superalgebra MH7. Phrthermore, we classify all the irreducible weak MH7-modules.

Bimodule and twisted representation of vertex operator algebras

In this paper, for a vertex operator algebra V with an automorphism g of order T, an admissible V-module M and a fixed nonnegative rational number n ∈1/T Z_+, we construct an A_(g,n)(V)-bimodule Ag,n(M) and study its properties, discuss the connections between bimodule A_(g,n)(M) and intertwining operators. Especially, bimodule A _(g,n)-1T(M) is a natural quotient of A_(g,n)(M) and there is a linear isomorphism between the space IM^k M Mjof intertwining operators and the space of homomorphisms HomA_(g,n)(V)(A_(g,n)(M) A_(g,n)(V)M^j(s), M^k(t)) for s, t ≤ n, M^j, M^k are g-twisted V modules, if V is g-rational.

Representations and Fusion Rules for the Orbifold Vertex Operator Algebras L_(sl_(2))(k,0)^(Z_(3))

For the cyclic group Z_(3)and a positive integer k,we study the representations of the orbifold vertex operator algebra L_(sl_(2))(k,0)^(Z_(3)).All the irreducible modules for L_(sl_(2))(k,0)^(Z_(3))are classified and constructed explicitly.Quantum dimensions and fusion rules for L_(sl_(2))(k,0)^(Z_(3))are completely determined.

Generalized twistors of nonlocal vertex algebras

We introduce and study the concept of （weak） pseudotwistor for a nonlocal vertex algebra, as a generalization of the notion of twistor. We give the relations between pseudotwistors and twisting operators. Furthermore, we study the inverse of an invertible weak pseudotwistor and the composition of two weak pseudotwistors.

仿射李代数■的顶点算子表示V_Q上的顶点代数结构(英文)

根据李代数的表示理论,研究了仿射李代数■的顶点算子表示VQ的顶点算子结构,通过形式级数的计算方法,证明了VQ是一个顶点算子代数.

算子李代数g(G,M)[σ]

构造了由算子构成的李代数g(G,M)[σ],然后讨论了算子李代数g(G,M)[σ]的代数结构。

TKK代数的一类表示

研究对应于欧氏空间中最小半格S的Tits-Kantor-Koecher李代数G(T(S))的泛中心扩张G^(T(S))的表示,这里T(S)为关于半格S的Jordan代数.首先将该李代数的结构等式表示为一系列形式幂级数等式,然后利用关于量子环面上gln型李代数的顶点表示及由群代数与对称代数组成的Fock空间,构造了一组作用于Fock空间的顶点算子.最后通过验证所定义的顶点算子满足该无穷维李代数的所有幂级数等式,证明了这些顶点算子在这一Fock空间上给出了TKK李代数G^(T(S))的一个Boson场顶点表示.

扭量子环面李代数的算子表示

主要给出了扭量子环面李代数gA[σ]的算子表示,证明了扭量子环面李代数gA[σ]同构于算子李代数g(G,M)[σ]。

广义TKK代数的一类Boson表示

研究对应于欧式空间中非格半格S的Tits-Kantor-Koecher(TKK)李代数g(T(S))的泛中心扩张广义TKK代数g(T(S))的一类Boson场表示.首先将广义TKK代数g(T)的结构等式表示为一系列形式幂级数等式,然后利用关于量子环面上gln型李代数的顶点表示及由群代数与对称代数组成的Fock空间,构造一组作用于Fock空间的顶点算子.最后,证明这些顶点算子在这Fock空间上给出了广义TKK代数g(T)的一个Boson场顶点表示.