scholarly journals When is the $q$-Multiplicity of a Weight a Power of $q$?

10.37236/8758 ◽  
2019 ◽  
Vol 26 (4) ◽  
Author(s):  
Pamela E. Harris ◽  
Margaret Rahmoeller ◽  
Lisa Schneider ◽  
Anthony Simpson
Keyword(s):  
Lie Algebras ◽  
Dynkin Diagram ◽  
Fibonacci Numbers ◽  
Simple Lie Algebras ◽  
Weight Multiplicity ◽  
Highest Weight ◽  
Multiplicity Formula ◽  
Exhaustive List

Berenshtein and Zelevinskii provided an exhaustive list of pairs of weights $(\lambda,\mu)$ of simple Lie algebras $\mathfrak{g}$ (up to Dynkin diagram isomorphism) for which the multiplicity of the weight $\mu$ in the representation of $\mathfrak{g}$ with highest weight $\lambda$ is equal to one. Using Kostant's weight multiplicity formula we describe and enumerate the contributing terms to the multiplicity for subsets of these pairs of weights and show that, in these cases, the cardinality of these contributing sets is enumerated by (multiples of) Fibonacci numbers. We conclude by using these results to compute the associated $q$-multiplicity for the pairs of weights considered, and conjecture that in all cases the $q$-multiplicity of such pairs of weights is given by a power of $q$.

scholarly journals ISOMORPHIC INDUCED MODULES AND DYNKIN DIAGRAM AUTOMORPHISMS OF SEMISIMPLE LIE ALGEBRAS

2015 ◽  
Vol 58 (1) ◽  
pp. 187-203
Author(s):  
JÉRÉMIE GUILHOT ◽  
CÉDRIC LECOUVEY
Keyword(s):  
Tensor Product ◽  
Weyl Group ◽  
Lie Algebras ◽  
Dynkin Diagram ◽  
Root Systems ◽  
The Other ◽  
Converse Problem ◽  
Highest Weight ◽  
Diagram Automorphisms ◽  
Levi Subalgebra

AbstractConsider a simple Lie algebra $\mathfrak{g}$ and $\overline{\mathfrak{g}}$ ⊂ $\mathfrak{g}$ a Levi subalgebra. Two irreducible $\overline{\mathfrak{g}}$-modules yield isomorphic inductions to $\mathfrak{g}$ when their highest weights coincide up to conjugation by an element of the Weyl group W of $\mathfrak{g}$ which is also a Dynkin diagram automorphism of $\overline{\mathfrak{g}}$. In this paper, we study the converse problem: given two irreducible $\overline{\mathfrak{g}}$-modules of highest weight μ and ν whose inductions to $\mathfrak{g}$ are isomorphic, can we conclude that μ and ν are conjugate under the action of an element of W which is also a Dynkin diagram automorphism of $\overline{\mathfrak{g}}$? We conjecture this is true in general. We prove this conjecture in type A and, for the other root systems, in various situations providing μ and ν satisfy additional hypotheses. Our result can be interpreted as an analogue for branching coefficients of the main result of Rajan [6] on tensor product multiplicities.

scholarly journals PURELY AFFINE ELEMENTARY su(N) FUSIONS

2002 ◽  
Vol 17 (19) ◽  
pp. 1249-1258 ◽  
Author(s):  
JØRGEN RASMUSSEN ◽  
MARK A. WALTON
Keyword(s):  
Linear Combination ◽  
Lie Algebras ◽  
Tensor Products ◽  
Field Theories ◽  
Conformal Field Theories ◽  
Simple Lie Algebras ◽  
Conformal Field ◽  
Highest Weight ◽  
Highest Weight Representations

We consider three-point couplings in simple Lie algebras — singlets in triple tensor products of their integrable highest weight representations. A coupling can be expressed as a linear combination of products of finitely many elementary couplings. This carries over to affine fusion, the fusion of Wess–Zumino–Witten conformal field theories, where the expressions are in terms of elementary fusions. In the case of su(4) it has been observed that there is a purely affine elementary fusion, i.e. an elementary fusion that is not an elementary coupling. In this paper we show by construction that there is at least one purely affine elementary fusion associated to every su (N > 3).

On factorization of the normalization SU(3) Clebsch–Gordan coefficients

1994 ◽  
Vol 72 (7-8) ◽  
pp. 511-518
Author(s):  
Yu. F. Smirnov
Keyword(s):  
Lie Algebras ◽  
Projection Operator ◽  
Simple Lie Algebras ◽  
Highest Weight ◽  
Multiplicity Free

The use of the factorized form of the extremal projection operator for the U(3) algebra allows one to prove the factorization of normalization Clebsch–Gordan coefficients [Formula: see text] (H is the highest weight) into the product of three simple SU(2) normalization Clebsch–Gordan coefficients in multiplicity free cases. A similar conclusion is conjectured to be valid for arbitrary simple Lie algebras (superalgebras) and their q analogs.

scholarly journals CODES, S-STRUCTURES, AND EXCEPTIONAL LIE ALGEBRAS

2019 ◽  
Vol 62 (S1) ◽  
pp. S14-S27 ◽  
Author(s):  
ISABEL CUNHA ◽  
ALBERTO ELDUQUE
Keyword(s):  
Lie Algebras ◽  
Simple Lie Algebras ◽  
Nonassociative Algebras ◽  
Exceptional Lie Algebras

AbstractThe exceptional simple Lie algebras of types E7 and E8 are endowed with optimal $\mathsf{SL}_2^n$ -structures, and are thus described in terms of the corresponding coordinate algebras. These are nonassociative algebras which much resemble the so-called code algebras.

Models of isotropic simple lie algebras

1979 ◽  
Vol 7 (17) ◽  
pp. 1835-1875 ◽  
Author(s):  
B.N. Allison
Keyword(s):  
Lie Algebras ◽  
Simple Lie Algebras

Nilpotent Orbits in Simple Lie Algebras and their Transverse Poisson Structures

2008 ◽  
Author(s):  
P. A. Damianou ◽  
H. Sabourin ◽  
P. Vanhaecke ◽  
Rui Loja Fernandes ◽  
Roger Picken
Keyword(s):  
Lie Algebras ◽  
Poisson Structures ◽  
Nilpotent Orbits ◽  
Simple Lie Algebras

scholarly journals On the construction of simple lie algebras

1973 ◽  
Vol 27 (1) ◽  
pp. 158-183 ◽  
Author(s):  
S Berman
Keyword(s):  
Lie Algebras ◽  
Simple Lie Algebras
Sign in / Sign up

Export Citation Format

Share Document