Weyl denominator
E503517
The Weyl denominator is a key product expression in Lie theory that appears in the Weyl character formula, encoding the alternating sum over the Weyl group and playing a central role in describing characters of irreducible representations of semisimple Lie algebras.
Statements (50)
| Predicate | Object |
|---|---|
| instanceOf |
invariant under root lattice translations up to sign
ⓘ
mathematical concept ⓘ object in Lie theory ⓘ |
| appearsIn |
Weyl character formula
NERFINISHED
ⓘ
theory of Macdonald identities and affine root systems ⓘ |
| context |
compact connected Lie groups
ⓘ
reductive algebraic groups ⓘ semisimple Lie algebras ⓘ |
| coreDefinition |
alternating sum over the Weyl group of exponentials of the Weyl vector
ⓘ
product over positive roots of (e^{α/2} − e^{−α/2}) ⓘ |
| definedOn |
Cartan subalgebra of a semisimple Lie algebra
ⓘ
maximal torus of a compact Lie group ⓘ |
| dependsOn | choice of positive root system ⓘ |
| encodes | alternating sum over the Weyl group ⓘ |
| expressedAs |
determinant of a matrix of exponentials in type A
ⓘ
product over positive roots of 2 sinh(α/2) ⓘ |
| field |
Lie theory
NERFINISHED
ⓘ
algebra ⓘ mathematical physics ⓘ representation theory ⓘ |
| generalizationOf | classical trigonometric product identities for SU(2) and SU(n) ⓘ |
| historicalOrigin | work of Hermann Weyl on representation theory of compact Lie groups ⓘ |
| invariantUnder | Weyl group up to sign ⓘ |
| property |
Weyl anti-invariant
ⓘ
changes sign under simple reflections ⓘ holomorphic on the complexified torus away from root hyperplanes ⓘ vanishes on root hyperplanes ⓘ |
| relatedTo |
Weyl character formula
NERFINISHED
ⓘ
Weyl integration formula NERFINISHED ⓘ Weyl numerator NERFINISHED ⓘ Weyl vector NERFINISHED ⓘ discriminant of a root system ⓘ |
| roleIn |
Harish-Chandra’s formulae for characters
NERFINISHED
ⓘ
Plancherel formula for compact Lie groups NERFINISHED ⓘ denominator of the Weyl character formula ⓘ description of characters of irreducible highest-weight representations ⓘ harmonic analysis on compact Lie groups ⓘ |
| specialCase |
Vandermonde determinant for type A root systems
ⓘ
sin-product formula for SU(2) ⓘ |
| symbol |
Δ
ⓘ
δ (in some conventions) ⓘ |
| usedFor |
computing characters of finite-dimensional irreducible representations
ⓘ
computing weight multiplicities via Weyl character formula ⓘ expressing partition functions in some conformal field theories ⓘ formulating Kac–Weyl character formula in affine Kac–Moody theory ⓘ formulating Weyl’s dimension formula ⓘ |
| uses |
Weyl group
NERFINISHED
ⓘ
half-sum of positive roots ⓘ root system ⓘ set of positive roots ⓘ |
Referenced by (1)
Full triples — surface form annotated when it differs from this entity's canonical label.