orthogonal group O(n+1,2)

E581259

The orthogonal group O(n+1,2) is the Lie group of linear transformations preserving a nondegenerate quadratic form of signature (n+1,2), playing a central role in conformal and Lie sphere geometry.

Jump to: Statements Referenced by

Statements (50)

Predicate Object
instanceOf Lie group
matrix group
orthogonal group
real algebraic group
actsConformallyOn n-dimensional sphere Sⁿ
actsOn Möbius space of Sⁿ
real vector space of dimension n+3
actsTransitivelyOn space of null lines in ℝ^{n+3}
contains reflections in nonisotropic vectors
hasCartanDecomposition 𝔰𝔬(n+1,2)=𝔨⊕𝔭
hasCartanInvolution conjugation by diag(I_{n+1},−I₂)
hasCenter {±I} for n+3 ≠ 2
hasConnectedComponent special orthogonal group SO(n+1,2) NERFINISHED
hasDimension (n+3)(n+2)/2
hasDoubleCover Spin(n+1,2)→SO(n+1,2)
hasFundamentalGroup ℤ for n+3 ≥ 3 (via SO⁰(n+1,2))
hasIdentityComponent SO⁰(n+1,2)
hasIwasawaDecomposition KAN with K ≅ O(n+1)×O(2)
hasLieAlgebra 𝔰𝔬(n+1,2)
hasMaximalCompactSubgroup O(n+1)×O(2) NERFINISHED
hasMaximalTorusDimension ⌊(n+3)/2⌋
hasParabolicSubgroupsCorrespondingTo conformal stabilizers of points on Sⁿ
hasRankOverℂ ⌊(n+3)/2⌋
hasRealRank 2
hasRootSystem type B₂ or D₂ as real rank 2 form
hasSignature (n+1,2)
hasSpecialSubgroup SO(n+1,2) NERFINISHED
hasSpinCover Spin(n+1,2) NERFINISHED
hasTwoComponents true
hasType indefinite orthogonal group NERFINISHED
hasWeylGroup finite reflection group of type B₂ or D₂ depending on n
identifiesWith group of Möbius transformations of Sⁿ up to finite kernel
isConformalGroupOf round conformal structure on Sⁿ
isDefinedOver
isGeneratedBy orthogonal reflections
isIsogenousTo PO(n+1,2) NERFINISHED
isIsometryGroupOf quadratic space of signature (n+1,2)
isNoncompact true
isRealFormOf complex Lie group SO(n+3,ℂ)
isReductive true
isSemisimple true
isSimpleModCenter true for n+3 ≥ 5
isSubgroupOf general linear group GL(n+3,ℝ) NERFINISHED
isUsedIn AdS/CFT-related models via conformal symmetry
Lie sphere geometry NERFINISHED
conformal geometry
representation theory of real reductive groups
theory of automorphic forms
preserves bilinear form of signature (n+1,2)
nondegenerate quadratic form of signature (n+1,2)

Referenced by (1)

Full triples — surface form annotated when it differs from this entity's canonical label.

Lie sphere geometry usesGroup orthogonal group O(n+1,2)