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Chongying Dong - One of the best experts on this subject based on the ideXlab platform.

Cuipo Jiang - One of the best experts on this subject based on the ideXlab platform.

Zongzhu Lin - One of the best experts on this subject based on the ideXlab platform.

Ching Hung Lam - One of the best experts on this subject based on the ideXlab platform.

  • sigma involutions associated with parafermion vertex Operator Algebra k mathfrak sl _2 k
    arXiv: Quantum Algebra, 2020
    Co-Authors: Ching Hung Lam, Hiromichi Yamada
    Abstract:

    An irreducible module for the parafermion vertex Operator Algebra $K(\mathfrak{sl}_2,k)$ is said to be of $\sigma$-type if an automorphism of the fusion Algebra of $K(\mathfrak{sl}_2,k)$ of order $k$ is trivial on it. For any integer $k \ge 3$, we show that there exists an automorphism of order $2$ of the subAlgebra of the fusion Algebra of $K(\mathfrak{sl}_2,k)^{\langle \theta \rangle}$ spanned by the irreducible direct summands of $\sigma$-type irreducible $K(\mathfrak{sl}_2,k)$-modules, where $\theta$ is an involution of $K(\mathfrak{sl}_2,k)$. We discuss some examples of such an automorphism as well.

  • retracted article modular framed vertex Operator Algebras
    European Journal of Mathematics, 2018
    Co-Authors: Chongying Dong, Ching Hung Lam, Li Ren
    Abstract:

    Framed vertex Operator Algebras over any Algebraically closed field whose characteristic is different from 2 and 7 are studied. In particular, the rationality of framed vertex Operator Algebras is established. For a code vertex Operator Algebra, the irreducible modules are constructed and classified. Moreover, a Z[\frac{1}{2}]-form for any framed vertex Operator Algebra over C is constructed. As a result, one can obtain a modular framed vertex Operator Algebra from any framed vertex Operator Algebra over C.

  • Modular framed vertex Operator Algebras
    arXiv: Quantum Algebra, 2017
    Co-Authors: Chongying Dong, Ching Hung Lam, Li Ren
    Abstract:

    Framed vertex Operator Algebras over any Algebraically closed field whose characteristic is different from 2 and 7 are studied. In particular, the rationality of framed vertex Operator Algebras is established. For a code vertex Operator Algebra, the irreducible modules are constructed and classified. Moreover, a Z[\frac{1}{2}]-form for any framed vertex Operator Algebra over C is constructed. As a result, one can obtain a modular framed vertex Operator Algebra from any framed vertex Operator Algebra over C.

  • on orbifold constructions associated with the leech lattice vertex Operator Algebra
    arXiv: Quantum Algebra, 2017
    Co-Authors: Ching Hung Lam, Hiroki Shimakura
    Abstract:

    In this article, we study orbifold constructions associated with the Leech lattice vertex Operator Algebra. As an application, we prove that the structure of a strongly regular holomorphic vertex Operator Algebra of central charge $24$ is uniquely determined by its weight one Lie Algebra if the Lie Algebra has the type $A_{3,4}^3A_{1,2}$, $A_{4,5}^2$, $D_{4,12}A_{2,6}$, $A_{6,7}$, $A_{7,4}A_{1,1}^3$, $D_{5,8}A_{1,2}$ or $D_{6,5}A_{1,1}^2$ by using the reverse orbifold construction. Our result also provides alternative constructions of these vertex Operator Algebras (except for the case $A_{6,7}$) from the Leech lattice vertex Operator Algebra.

  • the structure of parafermion vertex Operator Algebras
    arXiv: Quantum Algebra, 2009
    Co-Authors: Qing Wang, Chongying Dong, Ching Hung Lam, Hiromichi Yamada
    Abstract:

    It is proved that the parafermion vertex Operator Algebra associated to the irreducible highest weight module for the affine Kac-Moody Algebra A_1^{(1)} of level k coincides with a certain W-Algebra. In particular, a set of generators for the parafermion vertex Operator Algebra is determined.

Geoffrey Mason - One of the best experts on this subject based on the ideXlab platform.

  • Regularity of Rational Vertex Operator Algebras
    Advances in Mathematics, 1997
    Co-Authors: Chongying Dong, Geoffrey Mason
    Abstract:

    Rational vertex Operator Algebras, which play a fundamental role in rational conformal field theory (see [BPZ] and [MS]), single out an important class of vertex Operator Algebras. Most vertex Operator Algebras which have been studied so far are rational vertex Operator Algebras. Familiar examples include the moonshine module V ♮ ([B], [FLM], [D2]), the vertex Operator Algebras VL associated with positive definite even lattices L ([B], [FLM], [D1]), the vertex Operator Algebras L(l, 0) associated with integrable representations of affine Lie Algebras [FZ] and the vertex Operator Algebras L(cp,q, 0) associated with irreducible highest weight representations for the discrete series of the Virasoro Algebra ([DMZ] and [W]). A rational vertex Operator Algebra as studied in this paper is a vertex Operator Algebra such that any admissible module is a direct sum of simple ordinary modules (see Section 2). It is natural to ask if such complete reducibility holds for an arbitrary weak module (defined in Section 2). A rational vertex Operator Algebra with this property is called a regular vertex Operator Algebra. One motivation for studying such vertex Operator Algebras arises in trying to understand the appearance of negative fusion rules (which are computed by the Verlinde formula) for vertex Operator Algebras L(l, 0) for certain rational l (cf. [KS] and [MW]). In this paper we give several sufficient conditions under which a rational vertex Operator Algebra is regular. We prove that the rational vertex Operator Algebras V , L(l, 0) for positive integers l, L(cp,q, 0) and VL for positive definite even lattices L are regular. Our result for L(l, 0) implies that any restricted integrable module of level l for the corresponding affine Lie Algebra is a direct sum of irreducible highest weight integrable modules. This result is expected to be useful in comparing the construction of tensor product of modules for L(l, 0) in [F] based on Kazhdan-Lusztig’s approach [KL] with the construction of tensor product of modules [HL] in this special case. We should remark that VL in general is a vertex Algebra in the sense of [DL] if L is not positive definite. In this case we establish the complete reducibility of any weak module. Since the definition of vertex Operator Algebra is by now well-known, we do not define vertex Operator Algebra in this paper. We refer the reader to [FLM] and [FHL] for their elementary properties. The reader can find the details of the constructions of V ♮ and VL in [FLM], and L(l, 0) and L(cp,q, 0) in [DMZ], [DL], [FLM], [FZ], [L1] and [W].

  • simple currents and extensions of vertex Operator Algebras
    Communications in Mathematical Physics, 1996
    Co-Authors: Chongying Dong, Geoffrey Mason
    Abstract:

    We consider how a vertex Operator Algebra can be extended to an abelian interwining Algebra by a family of weak twisted modules which aresimple currents associated with semisimple weight one primary vectors. In the case that the extension is again a vertex Operator Algebra, the rationality of the extended Algebra is discussed. These results are applied to affine Kac-Moody Algebras in order to construct all the simple currents explicitly (except forE 8) and to get various extensions of the vertex Operator Algebras associated with integrable representations.

  • certain associative Algebras similar to u sl_ 2 and zhu s Algebra a v_ l
    arXiv: Quantum Algebra, 1996
    Co-Authors: Chongying Dong, Geoffrey Mason
    Abstract:

    It is proved that Zhu's Algebra for vertex Operator Algebra associated to a positive-definite even lattice of rank one is a finite-dimensional semiprimitive quotient Algebra of certain associative Algebra introduced by Smith. Zhu's Algebra for vertex Operator Algebra associated to any positive-definite even lattice is also calculated and is related to a generalization of Smith's Algebra.

  • Simple currents and extensions of vertex Operator Algebras
    Communications in Mathematical Physics, 1996
    Co-Authors: Chongying Dong, Geoffrey Mason
    Abstract:

    We consider how a vertex Operator Algebra can be extended to an abelian intertwining Algebra by a family of weak twisted modules which are {\em simple currents} associated with semisimple weight one primary vectors. In the case that the extension is again a vertex Operator Algebra, the rationality of the extended Algebra is discussed. These results are applied to affine Kac-Moody Algebras in order to construct all the simple currents explicitly (except for $E_8$) and to get various extensions of the vertex Operator Algebras associated with integrable representations.

  • Regularity of rational vertex Operator Algebras
    arXiv: Quantum Algebra, 1995
    Co-Authors: Chongying Dong, Geoffrey Mason
    Abstract:

    A regular vertex Operator Algebra is a vertex Operator Algebra such that any weak module (without grading) is a direct sum of ordinary irreducible modules. In this paper we give several sufficient conditions under which a rational vertex Operator Algebra is regular. We prove that the moonshine module vertex Operator Algebra $V^{\natural},$ the vertex Operator Algebras $L(l,0)$ associated with the integrable representations of affine Algebras of level $l,$ the vertex Operator Algebras $L(c_{p,q},0)$ associated with irreducible highest weight representations for the discrete series of the Virasoro Algebra and the vertex Operator Algebras $V_L$ associated with positive definite even lattices $L$ are regular. Our result for $L(l,0)$ implies that any restricted integrable module of level $l$ for the corresponding affine Lie Algebra is a direct sum of irreducible highest weight integrable modules. The space $V_L$ in general is a vertex Algebra if $L$ is not positive definite. In this case we establish the complete reducibility of any weak module.