A New Class of Representations of EALA Coordinated by Quantum Tori in Two Variables

2002 ◽  
Vol 45 (4) ◽  
pp. 672-685 ◽  
Author(s):  
S. Eswara Rao ◽  
Punita Batra
Keyword(s):  
Lie Algebras ◽  
Primitive Root ◽  
Irreducible Module ◽  
Affine Lie Algebras ◽  
Quantum Torus ◽  
New Class ◽  
Root Of Unity ◽  
Quantum Tori ◽  
Finite Dimensional

AbstractWe study the representations of extended affine Lie algebras where q is N-th primitive root of unity (ℂq is the quantum torus in two variables). We first prove that ⊕ for a suitable number of copies is a quotient of . Thus any finite dimensional irreducible module for ⊕ lifts to a representation of . Conversely, we prove that any finite dimensional irreducible module for comes from above. We then construct modules for the extended affine Lie algebras which is integrable and has finite dimensional weight spaces.

scholarly journals Coloured Generalised Young Diagrams for Affine Weyl-Coxeter Groups

10.37236/931 ◽  
2007 ◽  
Vol 14 (1) ◽  
Author(s):  
R. C. King ◽  
T. A. Welsh
Keyword(s):  
Lie Algebras ◽  
Coxeter Group ◽  
Coxeter Groups ◽  
Slight Variation ◽  
Affine Lie Algebras ◽  
Young Diagrams ◽  
Bijective Correspondence ◽  
Coxeter Number ◽  
Finite Dimensional ◽  
Dual Coxeter Number

Coloured generalised Young diagrams $T(w)$ are introduced that are in bijective correspondence with the elements $w$ of the Weyl-Coxeter group $W$ of $\mathfrak{g}$, where $\mathfrak{g}$ is any one of the classical affine Lie algebras $\mathfrak{g}=A^{(1)}_\ell$, $B^{(1)}_\ell$, $C^{(1)}_\ell$, $D^{(1)}_\ell$, $A^{(2)}_{2\ell}$, $A^{(2)}_{2\ell-1}$ or $D^{(2)}_{\ell+1}$. These diagrams are coloured by means of periodic coloured grids, one for each $\mathfrak{g}$, which enable $T(w)$ to be constructed from any expression $w=s_{i_1}s_{i_2}\cdots s_{i_t}$ in terms of generators $s_k$ of $W$, and any (reduced) expression for $w$ to be obtained from $T(w)$. The diagram $T(w)$ is especially useful because $w(\Lambda)-\Lambda$ may be readily obtained from $T(w)$ for all $\Lambda$ in the weight space of $\mathfrak{g}$. With $\overline{\mathfrak{g}}$ a certain maximal finite dimensional simple Lie subalgebra of $\mathfrak{g}$, we examine the set $W_s$ of minimal right coset representatives of $\overline{W}$ in $W$, where $\overline{W}$ is the Weyl-Coxeter group of $\overline{\mathfrak{g}}$. For $w\in W_s$, we show that $T(w)$ has the shape of a partition (or a slight variation thereof) whose $r$-core takes a particularly simple form, where $r$ or $r/2$ is the dual Coxeter number of $\mathfrak{g}$. Indeed, it is shown that $W_s$ is in bijection with such partitions.

Verma Modules over Quantum Torus Lie Algebras

2010 ◽  
Vol 62 (2) ◽  
pp. 382-399 ◽  
Author(s):  
Rencai Lü ◽  
Kaiming Zhao
Keyword(s):  
Lie Algebras ◽  
Sufficient Conditions ◽  
Necessary And Sufficient Conditions ◽  
Linear Functions ◽  
Verma Modules ◽  
Central Extensions ◽  
Quantum Torus ◽  
Infinite Dimensional ◽  
Quantum Tori ◽  
Necessary And Sufficient

AbstractRepresentations of various one-dimensional central extensions of quantum tori (called quantum torus Lie algebras) were studied by several authors. Now we define a central extension of quantum tori so that all known representations can be regarded as representations of the new quantum torus Lie algebras . The center of now is generally infinite dimensional.In this paper, Z-graded Verma modules over and their corresponding irreducible highest weight modules are defined for some linear functions . Necessary and sufficient conditions for to have all finite dimensional weight spaces are given. Also necessary and sufficient conditions for Verma modules e to be irreducible are obtained.

Integrable Representations for the Extended Affine Lie Algebra Coordinated by Quantum Tori in Two Variables

2014 ◽  
Vol 21 (03) ◽  
pp. 535-540 ◽  
Author(s):  
Fei Kong ◽  
Zhiqiang Li ◽  
Shaobin Tan ◽  
Qing Wang
Keyword(s):  
Lie Algebra ◽  
Type A ◽  
Quantum Torus ◽  
The Core ◽  
Quantum Tori ◽  
Finite Dimensional ◽  
Affine Lie Algebra ◽  
Extended Affine Lie Algebra ◽  
Integrable Modules

In this paper we classify the irreducible integrable modules for the core of the extended affine Lie algebra of type Ad-1 coordinated by ℂq with finite-dimensional weight spaces and the center acting trivially, where ℂq is the quantum torus in two variables.

scholarly journals A noncommutative sigma model

2013 ◽  
Vol 32 (1) ◽  
Author(s):  
Mauritz Van den Worm
Keyword(s):  
Sigma Model ◽  
Existence Theorems ◽  
Dimensional Representation ◽  
Lagrange Equations ◽  
Quantum Torus ◽  
Finite Dimensional Representation ◽  
Noncommutative Tori ◽  
Quantum Tori ◽  
Finite Dimensional ◽  
Noncommutative Sigma Model

We replace the classical string theory notions of mapping between parameter space and world-time with noncommutative tori mapping between these spaces. The dynamics of mappings between different noncommutative tori are studied and noncommutative versions of the Polyakov action and the Euler-Lagrange equations are derived. The quantum torus is studied in detail, as well as C*-homomorphisms between different quantum tori. A finite dimensional representation of the quantum torus is studied, and the partition function and other path integrals are calculated. At the end we prove existence theorems for mappings between different noncommutative tori.

scholarly journals GENERAL BRANCHING FUNCTIONS OF AFFINE LIE ALGEBRAS

1995 ◽  
Vol 10 (10) ◽  
pp. 823-830 ◽  
Author(s):  
STEPHEN HWANG ◽  
HENRIC RHEDIN
Keyword(s):  
Lie Algebras ◽  
Simple Proof ◽  
Affine Lie Algebras ◽  
Finite Dimensional ◽  
Brst Cohomology ◽  
Special Case ◽  
Finite Dimensional Algebras ◽  
Explicit Expressions

Explicit expressions are presented for general branching functions for cosets of affine Lie algebras ĝ with respect to subalgebras ĝ′ for the cases where the corresponding finite-dimensional algebras g and g′ are such that g is simple and g′ is either simple or sums of u(1) terms. A special case of the latter yields the string functions. Our derivation is purely algebraical and has its origin in the results on the BRST cohomology presented by us earlier. We will here give an independent and simple proof of the validity of our results. The method presented here generalizes in a straightforward way to more complicated g and g′ such as sums of simple and u(1) terms.

Vertex algebras and extended affine Lie algebras coordinated by rational quantum tori

2021 ◽  
Vol 569 ◽  
pp. 111-142
Author(s):  
Fulin Chen ◽  
Xiaoling Liao ◽  
Shaobin Tan ◽  
Qing Wang
Keyword(s):  
Lie Algebras ◽  
Vertex Algebras ◽  
Affine Lie Algebras ◽  
Quantum Tori
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