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.

All labels observed (3)

How this entity was disambiguated

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)
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)
linked to: O(n)
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)
hasSpinCover Spin(n+1,2)
hasTwoComponents true
hasType indefinite orthogonal group
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)
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)
isUsedIn AdS/CFT-related models via conformal symmetry
Lie sphere geometry
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)

How these facts were elicited

Referenced by (4)

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

Lie sphere geometry usesGroup orthogonal group O(n+1,2)
Lie sphere group relatedTo orthogonal group O(n+1,2)
orthogonal group O(n+1,2) hasConnectedComponent special orthogonal group SO(n+1,2)
linked to: orthogonal group O(n+1,2)
orthogonal group O(n+1,2) hasType indefinite orthogonal group
linked to: orthogonal group O(n+1,2)