finite rotation group




By a finite rotation group one means a finite subgroup of a rotation group, hence of a special orthogonal group SO(n)SO(n) or spin group Spin(n)Spin(n) or similar.

The finite subgroups of SO(3) and SU(2) follow an ADE classification (theorem below).


Finite subgroups of O(3)O(3), SO(3)SO(3) and Spin(3)Spin(3)


(ADE classification of finite subgroups of SO(3) and Spin(3)\simeq SU(2))

The finite subgroups of the special orthogonal group SO(3)SO(3) as well as the finite subgroups of the special unitary group SU(2) are, up to conjugation, given by the following classification:

ADE classification and McKay correspondence

Dynkin diagram/
Dynkin quiver
Platonic solidfinite subgroups of SO(3)finite subgroups of SU(2)simple Lie group
A n1A_{n \geq 1}cyclic group
cyclic group
special unitary group
D4Klein four-group
D 4 2× 2D_4 \simeq \mathbb{Z}_2 \times \mathbb{Z}_2
quaternion group
2D 42 D_4 \simeq Q8
D n4D_{n \geq 4}dihedron,
dihedral group
D 2(n2)D_{2(n-2)}
binary dihedral group
2D 2(n2)2 D_{2(n-2)}
special orthogonal group
E 6E_6tetrahedrontetrahedral group
binary tetrahedral group
E 7E_7cube,
octahedral group
binary octahedral group
E 8E_8dodecahedron,
icosahedral group
binary icosahedral group

Here under the double cover projection (using the exceptional isomorphism SU(2)Spin(3)SU(2) \simeq Spin(3))

SU(2)Spin(3)πSO(3) SU(2) \simeq Spin(3) \overset{\pi}{\longrightarrow} SO(3)

all the finite subgroups of SU(2)SU(2) except the odd-order cyclic groups are the preimages of the corresponding finite subgroups of SO(3)SO(3), in that we have pullback diagrams

exp(πi1n) = /(2n) AA Spin(2) AA Spin(3) (pb) (pb) π Ad exp(πi1n) = /n AA SO(2) AA SO(3) \array{ \left\langle \exp \left( \pi \mathrm{i} \tfrac{1}{n} \right) \right\rangle & = & \mathbb{Z}/(2n) &\overset{\phantom{AA}}{\hookrightarrow}& Spin(2) &\overset{\phantom{AA}}{\hookrightarrow}& Spin(3) \\ && \big\downarrow &{}^{(pb)}& \big\downarrow &{}^{(pb)}& \big\downarrow^{ \mathrlap{\pi} } \\ \left\langle Ad_{ \exp \left( \pi \mathrm{i} \tfrac{1}{n} \right) } \right\rangle & = & \mathbb{Z}/n &\overset{\phantom{AA}}{\hookrightarrow}& SO(2) &\overset{\phantom{AA}}{\hookrightarrow}& SO(3) }

exhibiting the even order cyclic groups as subgroups of Spin(2), including the the minimal case of the group of order 2

exp(πi)=1 = /2 AA Spin(2) AA Spin(3) (pb) (pb) π Ad exp(πi)=e = 1 AA SO(2) AA SO(3) \array{ \left\langle \exp \left( \pi \mathrm{i} \right) = -1 \right\rangle & = & \mathbb{Z}/2 &\overset{\phantom{AA}}{\hookrightarrow}& Spin(2) &\overset{\phantom{AA}}{\hookrightarrow}& Spin(3) \\ && \big\downarrow &{}^{(pb)}& \big\downarrow &{}^{(pb)}& \big\downarrow^{ \mathrlap{\pi} } \\ \left\langle Ad_{ \exp \left( \pi \mathrm{i} \right) } = e \right\rangle & = & 1 &\overset{\phantom{AA}}{\hookrightarrow}& SO(2) &\overset{\phantom{AA}}{\hookrightarrow}& SO(3) }

as well as

exp(πi1n),j = 2D 2n AA Pin (2) AA Spin(3) (pb) (pb) π Ad exp(πi1n),Ad j D 2n AA O(2) AA SO(3) \array{ \left\langle \exp\left( \pi \mathrm{i} \tfrac{1}{n} \right), \, \mathrm{j} \right\rangle &=& 2 D_{2n} &\overset{\phantom{AA}}{\hookrightarrow}& Pin_-(2) &\overset{\phantom{AA}}{\hookrightarrow}& Spin(3) \\ && \big\downarrow &{}^{(pb)}& \big\downarrow &{}^{(pb)}& \big\downarrow^{ \mathrlap{\pi} } \\ \left\langle Ad_{\exp\left( \pi \mathrm{i} \tfrac{1}{n} \right) }, \, Ad_{\mathrm{j}} \right\rangle && D_{2n} &\overset{\phantom{AA}}{\hookrightarrow}& O(2) &\overset{\phantom{AA}}{\hookrightarrow}& SO(3) }

exhibiting the binary dihedral groups as sitting inside the Pin(2)-subgroup of Spin(3),

but only commuting diagrams

exp(2πi12n+1) = /(2n+1) AA Spin(3) π Ad exp(2πi12n+1) = /(2n+1) AA SO(2) AA SO(3) \array{ \left\langle \exp \left( 2 \pi \mathrm{i} \tfrac{1}{{2n+1}} \right) \right\rangle & = & \mathbb{Z}/(2n+1) &&\overset{\phantom{AA}}{\hookrightarrow}&& Spin(3) \\ && \big\downarrow && && \big\downarrow^{ \mathrlap{\pi} } \\ \left\langle Ad_{ \exp \left( 2 \pi \mathrm{i} \tfrac{1}{2n+1} \right) } \right\rangle & = & \mathbb{Z}/(2n+1) &\overset{\phantom{AA}}{\hookrightarrow}& SO(2) &\overset{\phantom{AA}}{\hookrightarrow}& SO(3) }

for the odd order cyclic subgroups.

This goes back to (Klein 1884, chapter I). Full proof for SO(3)SO(3) is spelled out for instance in (Rees 05, theorem 11, De Visscher 11). The proof for the case of SL(2,)SL(2,\mathbb{C}) is spelled out in (Miller-Blichfeldt-Dickson 16) reviewed in (Serrano 14, section 2). The proof of the case for SU(2)SU(2) given the result for SO(3)SO(3) is spelled out in Keenan 03, theorem 4.

Finite subgroups of O(4)O(4), SO(4) and Spin(4)

For classification of the finite subgroups of O(4)O(4) see (duVal 65, Conway-Smith 03)

For finite subgroups of Spin(4): MFF 12, appendix B.

In this classification, the symmetry group of the 120-cell and hence that of the 600-cell is the quotient group (2I×2I)/ 2(2 I \times 2 I)/\mathbb{Z}_2 by the cyclic group of order 2 of the direct product group of two copies of the binary icosahedral group (SadocMosseri 89, p. 172, see MFF 12, table 16).

Finite subgroups of O(5)O(5)

For classification of the finite subgroups of O(5)O(5) see Mecchia-Zimmermann 10


Subgroup lattice

The subgroup lattice of SU(2) under the three exceptional finite subgroups 2T, 2O, 2I (from Theorem ) looks as follows:

This is obtained from the subgroup lattice as shown on GroupNames for 2I2I \simeq SL(2,5) and 2O2O \simeq CSU(2,3)

See also Goncalves-Guaschi 11, appendix.

Group cohomology


(group cohomology of finite subgroups of SU(2))

Let G ADEG_{ADE} be a finite subgroup of SU(2). Then its group cohomology with integer coefficients is as follows:

H grp n(G ADE,){ | n=0 G ADE ab | n=2mod4 /|G ADE| | npositive multiple of4 0 | otherwise H^n_{grp}(G_{ADE}, \mathbb{Z}) \;\simeq\; \left\{ \array{ \mathbb{Z} &\vert& n = 0 \\ G_{ADE}^{ab} &\vert& n = 2 \, mod \, 4 \\ \mathbb{Z}/{\vert G_{ADE}\vert} &\vert& n \, \text{positive multiple of} \, 4 \\ 0 &\vert& \text{otherwise} } \right.

Here G ADE abG_{ADE}^{ab} denotes the abelianization of G ADEG_{ADE} and |G ADE|\vert G_{ADE}\vert its cardinality, hence /|G ADE|\mathbb{Z}/{\vert G_{ADE}\vert} the cyclic group whose order is the cardinality of G ADEG_{ADE}.

The group homology with integer coefficients is

H n grp(G ADE,){ | n=0 G ADE ab | n=1mod4 /|G ADE| | n=3mod4 0 | otherwise H_n^{grp}(G_{ADE}, \mathbb{Z}) \;\simeq\; \left\{ \array{ \mathbb{Z} &\vert& n = 0 \\ G^{ab}_{ADE} &\vert& n = 1 \, mod \, 4 \\ \mathbb{Z}/{\vert G_{ADE}\vert} &\vert& n= 3 \,mod\, 4 \\ 0 &\vert& \text{otherwise} } \right.

For pointers to proofs see for instance Epa-Ganter 16, section 4.


In discussion of 11-dimensional supergravity on spacetimes with ADE-singularities, the special case

H grp 4(G ADE,)H 3( 4G ADE,U(1))/|G ADE| \underset{ \simeq H^3( \mathbb{C}^4 \sslash G_{ADE}, U(1)) }{ \underbrace{ H^4_{grp}(G_{ADE}, \mathbb{Z}) }} \;\simeq\; \mathbb{Z}/{\vert G_{ADE} \vert }

of Prop. , regarded as expressing orbifold cohomology of an ADE singularity, as shown under the brace, witnesses the possible torsion supergravity C-field flux of M5-branes wrapped on torsion homology 3-cycles (“discrete torsion”, see Aharony-Bergman-Jafferis 08, p. 8 and BDHKMMS 01, section 4.6.2).


Finite subgroups of SO(3)SO(3) and Spin(3)Spin(3)

The classification in Theorem goes back to

  • Felix Klein, chapter I of Vorlesungen über das Ikosaeder und die Auflösung der Gleichungen vom fünften Grade, 1884, translated as Lectures on the Icosahedron and the Resolution of Equations of Degree Five by George Morrice 1888, online version

Textbook accounts include

  • G. A. Miller, H. F. Blichfeldt, L. E. Dickson, Theory and applications of finite groups, Dover, New York, 1916

  • Klaus Lamotke, Regular Solids and Isolated Singularities, Vieweg 1986

  • Elmer Rees, Notes on Geometry, Springer 2005

see also

  • Javier Carrasco Serrano, Finite subgroups of SL(2,)SL(2,\mathbb{C}) and SL(3,)SL(3,\mathbb{C}), Warwick 2014 (pdf)

Complete proof of the classification of the finite subgroups of SO(3)SO(3) is also spelled out in

Based on the classification of the finite subgroups of SO(3)SO(3), full proof of that of the finite subgroups of SU(2)SU(2) is spelled out in

  • Adam Keenan, Which finite groups act freely on spheres?, 2003 (pdf)

See also

Discussion of the lattice of subgroups of the three exceptional subgroups is in

  • Daciberg Lima Gonçalves, John Guaschi, The Subgroups of the Binary Polyhedral Groups, Appendix of The classification of the virtually cyclic subgroups of the sphere braid groups, Springer (Ed.) (2013) 112 (arXiv:1110.6628, pdf)

The universal higher central extension of finite subgroups of SU(2)SU(2) (“Platonic 2-groups”) are discussed in

Finite subgroups of O(4)O(4)

  • Patrick du Val, Homographies, Quaternions and Rotations, Oxford Mathematical Monographs, Clarendon Press (1964)

    also(?): Journal of the London Mathematical Society, Volume s1-40, Issue 1 (1965) (doi:10.1112/jlms/s1-40.1.569b)

  • John Conway, D. A. Smith, On quaternions and octonions: their geometry, arithmetic and

    symmetry_ A K Peters Ltd., Natick, MA, 2003

  • Paul de Medeiros, José Figueroa-O'Farrill, appendix B of Half-BPS M2-brane orbifolds, Adv. Theor. Math. Phys. Volume 16, Number 5 (2012), 1349-1408. (arXiv:1007.4761, Euclid)

  • J. F. Sadoc, R. Mosseri, Icosahedral order, curved space and quasicrystals, in Jaric, Gratias (eds.) Extended icosahedral structures, 1989 (GoogleBooks)

Finite subgroups of O(5)O(5)

  • Mattia Mecchia, Bruno Zimmermann, On finite groups acting on homology 4-spheres and finite subgroups of SO(5)SO(5), Topology and its Applications 158.6 (2011): 741-747 (arXiv:1001.3976)

Last revised on March 22, 2019 at 09:23:18. See the history of this page for a list of all contributions to it.