A class of irreducible modules for the extended affne Lie algebra ■

We construct a class of modules for extended affine Lie algebra gl l（Cq） by using the free fields. A necessary and sufficient condition is given for those modules being irreducible.

GF(2)-modules for Sz (q) wrC_t

In this note the authors investigates the property of the GF(2)-modules for the wreath products Sz(q)wrCt,and establish some sufficient condition for a Sz(q)wrCt, GF(2)-module to be natural.

Irreducible Weight Modules over the Twisted SchrSdinger-Virasoro Algebra

It is shown that the support of an irreducible weight module over the SchrSdinger-Virasoro Lie algebra with an infinite-dimensional weight space coincides with the weight lattice, and all nontrivial weight spaces of such a module are infinite-dimensional. As a by-product, it is obtained that every simple weight module over Lie algebra of this type with a nontrivial finite-dimensional weight space is a Harish-Chandra module.

Strongly Irreducible Submodules of Modules

Strongly irreducible submodules of modules are defined as follows： A submodule N of an Rmodule M is said to be strongly irreducible if for submodules L and K of M, the inclusion L ∩ K ∈ N implies that either L ∈ N or K ∈ N. The relationship among the families of irreducible, strongly irreducible, prime and primary submodules of an R-module M is considered, and a characterization of Noetherian modules which contain a non-prime strongly irreducible submodule is given.

Irreducible A1（1）-modules from modules over two-dimensional non-abelian Lie algebra

For any module V over the two-dimensional non-abelian Lie algebra b and scalar a ∈C, we define a class of weight modules Fα（V） with zero central charge over the affine Lie algebra A（1）. These weight modules have infinite- dimensional weight spaces if and only if V is infinite dimensional. In this paper, we will determine necessary and sufficient conditions for these modules Fα（V） to be irreducible. In this way, we obtain a lot of irreducible weight A1（1）-modules with infinite-dimensional weight spaces.

Some Results on the Problems of Block Theory

In this paper, we obtain two results on Brauers k(B) problem about finite groups under some conditions. Furthermore, we obtain that Olssons conjecture holds under the same conditions on the finite groups.

IRREDUCIBLE REPRESENTATIONS FOR THE AFFINE-VIRASORO LIE ALGEBRA OF TYPE B_l

An explicit construction of irreducible representations for the affine-Virasoro Lie algebra of type Bl, through the use of vertex operators and certain oscillator representations of the Virasoro algebra, is given.

Non-weight modules over the mirror Heisenberg-Virasoro algebra

In this paper,we study irreducible non-weight modules over the mirror Heisenberg-Virasoro algebra D,including Whittaker modules,U(Cd_(0))-free modules and their tensor products.More precisely,we give the necessary and sufficient conditions for the Whittaker modules to be irreducible.We determine all the D-module structures on U(Cd_(0)),and find the necessary and sufficient conditions for these modules to be irreducible.At last,we determine the necessary and sufficient conditions for the tensor products of Whittaker modules and U(Cd_(0))-free modules to be irreducible,and obtain that any two such tensor products are isomorphic if and only if the corresponding Whittaker modules and U(Cd_(0))-free modules are isomorphic.These lead to many new irreducible non-weight modules over D.

On Nonsingular Modules over Infinite-Dimensional Simple Novikov Algebra of Characteristic 0

In this paper we show that an A-module is a direct sum of a trivial module and a nosingular module,and we also give the structure of nonsingular module over infinite dimensional simple Novikov algebras of types (Ⅱ) and (Ⅲ) over a field F of Characteristic 0.

A New Multiplicity Formula for the Weyl Modules of Type B and C

A monomial basis and a filtration of subalgebras for the universal enveloping algebra U（gl） of a complex simple Lie algebra gl of type Bl and Cl are given, and the decomposition of the Weyl module V （λ） as a U（gl）-module into a direct sum of Weyl modules V （μ）’s as U（gl-1）modules is described. In particular, a new multiplicity formula for the Weyl module V （λ） is obtained in this note.

Singular Conformal Oscillator Representations of Orthosymplectic Lie Superalgebras

In our earlier paper,we generalize the one-parameter(c)family of inhomogeneous firstorder differential operator representations of the orthogonal Lie algebras arising from conformal transformations to those of orthosymplectic Lie super algebras,and determine the irreducible condition.This paper deals with the cases when the irreducible condition fails.We prove that if n-m-1>0 and c is an integer satisfying 1≤c≤n-m-1,the representation of osp(2n+2|2m)has a composition series of length 2,and when n-m-1≥0 and c∈-N,the representation of osp(2n+2|2m)has a composition series of length 3,where N is the set of nonnegative integers.Moreover,we show that if c∈(max{n-m,0}-1/2-N)∪(-N),the representation of osp(2n+3|2m)has a composition series of length 2.In particular,we obtain an explicit presentation of the irreducible module with highest weight lλ2-λ1,where l is any positive integer and it is not a generalized Verma module.

Conformal oscillator representations of orthogonal Lie algebras

The conformal transformations with respect to the metric defining the orthogonal Lie algebra o（n, C） give rise to a one-parameter （c） family of inhomogeneous first-order differential operator representations of the orthogonal Lie algebra o（n ＋ 2, C）. Letting these operators act on the space of exponential-polynomial functions that depend on a parametric vector a^→∈ C^n, we prove that the space forms an irreducible o（n ＋ 2, C）-module for any c ∈ C if a^→ is not on a certain hypersurface. By partially swapping differential operators and multiplication operators, we obtain more general differential operator representations of o（n＋2, C） on the polynomial algebra in n variables. Moreover, we prove that l forms an infinite-dimensional irreducible weight o（n ＋2, C）-module with finite-dimensional weight subspaces if c Z/2.

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.

Partial Differential Equation Approach to E_7

By solving certain partial differential equations, we find the explicit decomposition of the polynomial algebra over the 56-dimensional basic irreducible module of the simple Lie algebra E7 into a sum of irreducible submodules. This essentially gives a partial differential equation proof of a combinatorial identity on the dimensions of certain irreducible modules of E7. We also determine two three-parameter families of irreducible submodules in the solution space of Cartan＇s well-known fourth-order Ez-invariant partial differential equation.

On Polynomial Representations of Strange Lie Superalgebras of Q-Type

In this paper, both canonical and noncanonical polynomial representations of Lie super- algebara of Q-type are investigated. It turns out that not all these representations are completely reducible. Moreover, the representation spaces has only two proper submodules when it is completely reducible, and has a unique composition series when it is not completely reducible.

Grothendieck rings of a class of Hopf algebras of Kac-Paljutkin type

We construct the Grothendieck rings of a class of 2n^(2)dimensional semisimple Hopf Algebras H_(2n)^(2),which can be viewed as a generalization of the 8 dimensional Kac-Paljutkin Hopf algebra H8.All irreducible H_(2n)^(2)-modules are classified.Furthermore,we describe the Grothendieck rings r(H_(2n)^(2))by generators and relations explicitly.

Representations of Four-Derivation Lie Algebras of Block Type

Block introduced certain analogues of the Zassenhaus algebras over a field of characteristic 0. The nongraded infinite-dimensional simple Lie algebras of Block type constructed by Xu can be viewed as generalizations of the Block algebras. In this paper, we construct a family of irreducible modules in terms of multiplication and differentiation operators on ＂polynomials＂ for four-devivation nongraded Lie algebras of Block type based on the finite-dimensional irreducible weight modules with multiplicity one of general linear Lie algebras. We also find a new series of submodules from which some irreducible quotient modules are obtained.

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.