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User:Tomruen/Point group symmetries

From Wikipedia, the free encyclopedia

Point group symmetries can be defined as discrete Coxeter groups and continuous orthogonal groups that leave one point unchanged. Both include rotations and reflections, while chiral half groups exist with only rotations. Symmetries with reflections are called full symmetry, while without reflections are called rotational or proper symmetry.

Introduction

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Orthogonal groups

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All point groups of n-dimensions can be seen as subgroups of orthogonal groups O(n) or special orthogonal groups SO(n) = O(n)/O(1), disallowing reflections. Orientation in space is represented by n orthonormal basis vectors u1, u2... un. Put into a matrix, this basis determinant can be +1 or -1 representing direct and mirrored transformations.

Many subgroups can be represented as Cartesian products of lower dimensional symmetries. For example O(a)×O(b) is a subgroup of O(a+b).

A point in n-dimensions has O(n) symmetry. A segment in n-dimensions has O(n-1) symmetry. A k-dimensional object in n dimension will have O(n-k) symmetry beyond its own symmetry in k-dimension.

Coxeter groups and notation

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Coxeter notation is a system of classifying symmetry groups, describing the angles between fundamental reflections of a Coxeter group in a bracketed notation expressing the structure of a Coxeter-Dynkin diagram, with modifiers to indicate certain subgroups. The notation is named after H. S. M. Coxeter, and has been more comprehensively defined by Norman Johnson.

There is a direct correspondence between Coxeter (bracket) notation and Coxeter-Dynkin diagram. The numbers in the bracket notation represent the mirror reflection orders in the branches of the Coxeter diagram. It uses the same simplification, suppressing 2s between orthogonal mirrors.

The Coxeter notation is simplified with exponents to represent the number of branches in a row for linear diagram. So the An group is represented by [3n−1], to imply n nodes connected by n−1 order-3 branches. Example A2 = [3,3] = [32] represents diagrams .

Chiral subgroups are represented with a + symbol. [3] is the dihedral group, Dih3, order 6, while [3]+ is the cyclic group order 3.

Chiral subgroups can be applied to portions of a Coxeter diagram that are isolated by all even-order branches. [3+,4], is the pyritohedral group, order 24, while [3+,4,1+], , becomes chiral tetrahedral group [3,3]+, , order 12.

Coxeter graphs that are unconnected can be expressed as direct products, while connected rotational groups can be expressed as semidirect products.

Objects defined by composite

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Johnson defined product, sum, and join operators for constructing higher dimensional polytopes from lower. Johnson defines ( ) as a point (0-polytope), { } is a line segment defined between two points (1-polytope). Many vertex figures for uniform polytopes can be expressed with these operators.

A product operator, ×, defines rectangles and prisms with independent proportions. dim(A×B) = dim(A)+dim(B).

For instance { }×{ } is a rectangle, symmetry [2], (a lower symmetry form of a square), and {4}×{ } is a square prism, symmetry [4,2] (a lower symmetry form of a cube), and {4}×{4} is called a duoprism in 4-dimensions, symmetry [4,2,4] (a lower symmetry form of a tesseract).

A sum operator, +, makes duals to the prisms. dim(A+B) = dim(A)+dim(B).

For instance, { }+{ } is a rhombus or fusil in general, symmetry [2], {4}+{ } is a square bipyramid, symmetry [4,2] (lower symmetry form of a regular octahedron), and {4}+{4} is called a duopyramid in 4-dimensions, symmetry [4,2,4] (a lower symmetry form of the 16-cell).

The product and sum operators are related by duality: !(A×B)=!A+!B and !(A+B)=!A×!B, where !A is dual polytope of A.

A join operator, ∨, makes pyramidal composites, orthogonal orientations with an offset direction as well, with edges between all pairs of vertices across the two. dim(A∨B) = dim(A)+dim(B)+1.

The isosceles triangle can be seen as ( )∨{ }, symmetry [ ], and tetragonal disphenoid is { }∨{ }, symmetry [2]. A square pyramid is {4}∨( ), symmetry [4,1]. A 1 branch is symbolic, representing [4,2,1+], or , having an orthogonal mirror inactivated by an alternation.

The join operator is self-related by duality: !(A∨B)=!A∨!B. More generally any expression of these operators can be dualed by replacing polytopes by dual, and swapping product and sum operators.

Polytopes constructed by:

  1. Products are orthotopes (prisms)
  2. Sums are orthoplexes (bipyramids or fusils)
  3. Products and sums are Hanner polytopes
  4. Join are simplexes (pyramids)

Continuous symmetry objects are constructed by:

  1. Products are cylinders: circle×segment (3D), circle×circle (4D), sphere×segment (4D), sphere×circle (5D), etc.
  2. Sums are bicones: circle+segment (3D), circle+circle (4D), sphere+segment (4D), sphere+circle (5D), etc.
  3. Joins are cones: circle∨point (3D), circle∨segment (4D), sphere∨point (5D), circle∨circle (5D), sphere∨segment (5D), sphere∨circle (6D), etc.

Example coordinates with operators:

  • { }×{ } = (±1; ±1) = rectangle or square in 2D, symmetry [2], , order 4
    • {4}×{ } = (±1, ±1; ±1) = rectangular parallelepiped or cube in 3D, symmetry [4,2], , order 16
    • {4}×{4} = (±1, ±1; ±1, ±1) = 4-4 duoprism or tesseract in 4D, symmetry [4,2,4], , order 64
  • { }+{ } = (±1, 0), (0, ±1) = rhombus or square in 2D, , order 4
    • {4}+{ } = (±1, ±1; 0), (0, 0; ±1) = square-segment duopyramid = octahedron in 3D, symmetry [4,2], , order 16
    • {4}+{4} = (±1, ±1; 0, 0), (0, 0; ±1, ±1) = square-square duopyramid = 16-cell in 4D, symmetry [4,2,4], , order 64
  • { }∨{ } = (±1; -1; 0), (0; +1; ±1) = segment-segment pyramid = tetragonal disphenoid in 3D, symmetry [2,1,2],
    • ( )∨( ) = { } = (±1) = segment in 1D, symmetry [1], , order 2
    • { }∨( ) = (±1; -1), (0; +1) = isosceles triangle in 2D, symmetry [1], , order 2
    • {4}∨( ) = (±1, ±1; -1), (0, 0; +1) = square pyramid in 3D, symmetry [4,1], , order 16
    • {4}∨{ } = (±1, ±1; -1; 0), (0, 0; +1; ±1) = square-segment pyramid in 4D, symmetry [4,2,1], , order 16
    • {4}∨{4} = (±1, ±1; -1; 0, 0), (0, 0; +1; ±1, ±1) = square-square pyramid in 5D, symmetry [4,2,4,1], , order 64

1D

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O(1) is a single orthogonal reflection, dihedral symmetry order 2, Dih1. SO(1) is just the identity.

# Rank 1 groups Order Other names Example geometry Example finite subgroups
1 O(1) 2 Dih1 Full symmetry a line segment, point [ ] =
1b SO(1) 1 C1 Direct symmetry, ray [ ]+ =

2D

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Continuous symmetries in 2-space can be classified as products of orthogonal groups O(2) or special orthogonal groups SO(2) = O(2)/O(1).

# Rank 2 groups Other names Example geometry Example finite subgroup
Bracket Graph Order
1 O(2) Dih Full symmetry a circle, , point [p] 2p
1b SO(2) C Circle group, Direct [p]+ p
1c Dih(6) ⊂ O(2) Dih6 Hexagon, {6} [[3]] = [6] 12
1d C(6) ⊂ SO(2) C6 [[3]]+ = [6]+ 6
1e Dih(5) ⊂ O(2) Dih5 Pentagon, {5} [5] 10
1f C(5) ⊂ SO(2) C5 [5]+ 5
1g Dih(3) ⊂ O(2) Dih3 Equilateral triangle, {3}
reuleaux triangle
[3] 6
1h C(3) ⊂ SO(2) C3 [3]+ 3
2 O(1)×O(1)×2! Dih4 Square, {4} [[2]] = [4] 8
2b (O(1)×O(1)×2!)/O(1) C4 [[2]]+ = [4]+ 4
2c O(1)×O(1) Dih1×Dih1=Dih2 Rectangle, { }2, rhombus
ellipse, stadium, lens
[ ]×[ ] = [2] 4
2d (O(1)×O(1))/O(1) C2 Half turn Parallelogram, zonogons [2]+ 2
3 O(1)×SO(1) Dih1 Isosceles triangle, { }∨( )
kite, isosceles trapezoids
oval, crescent, parabola, circular segment
[1] 2
3b SO(1)×SO(1) C1 Scalene triangle, ( )∨( )∨( )
irregular quadrilateral, arbelos
[1]+ 1

3D

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Continuous symmetries in 3-space can be classified as products of orthogonal groups O(n) or special orthogonal groups SO(n) = O(n)/O(1), along with semidirect products with half turns, C2.

# Rank 3 groups Other names Example geometry Example finite subgroup
Bracket Product Graph Order
1 O(3) Full symmetry of the sphere, , point [4,3] 48
1b SO(3) Sphere group Rotational symmetry [4,3]+ 24
2 O(2)×O(1)
O(2)⋊C2
Dih×Dih1
Dih⋊C2
Full symmetry of a circle , segment, { }
spheroid, torus, cylinder, bicone, hyperboloid, capsule, lemon
Full circular symmetry with half turn

[p,2] [p]×[ ] 4p
2b SO(2)×O(1) C×Dih1 Rotational symmetry with reflection [p+,2] [p]+×[ ] 2p
2c SO(2)⋊C2 C⋊C2 Rotational symmetry with half turn [p,2]+ ([p]+×[ ])+ 2p
3 O(2)×SO(1) Dih
Circular symmetry
Full symmetry of a hemisphere, spherical segment
cone, paraboloid or any surface of revolution
, , [p,1] [p]×[ ]+ 2p
3b SO(2)×SO(1) C
Circle group
Rotational symmetry [p,1]+ ([p]×[ ]+)+ p
4 O(1)×O(1)×O(1)×3! [4,3] Full of symmetry of cube, {4,3} [3[2,2]] = [4,3] 48
4b (O(1)×O(1)×2!)×O(1) [4,2] Full symmetry of square prism, {4}×{ } [[2],2] = [4,2] [4]×[ ]+ 16
4c O(1)×O(1)×O(1) Dih3
1
Full of symmetry of rectangular cuboid, { }3 [2,2] [ ]×[ ]×[ ] 8
4d (O(1)×O(1)×O(1))/O(1) Direct rectangular cuboid
Rhombic disphenoid
[2,2]+ ([ ]×[ ]×[ ])+ 4
5 (O(1)×O(1)×2!)×SO(1) Dih4 Full symmetry of square pyramid, {4}∨( ) [[2],1] = [4,1] [4]×[ ]+ 8
5b O(1)×O(1)×SO(1) Dih2
1
= Dih2
Full symmetry of rectangle pyramid, { }2∨( ) [2,1] [ ]×[ ]×[ ]+ 4
5c (O(1)×O(1)×SO(1))/O(1) C2 Direct rectangular pyramid [2,1]+ ([2]×[ ])+ 2
6 (O(1)×(SO(1)×SO(1)×2!))×2! Full symmetry of tetragonal disphenoid, Aut({ }∨{ }) [4,2+] 8
6b O(1)×(SO(1)×SO(1)×2!) Dih1×Dih1 = Dih2 Full symmetry of tetragonal disphenoid, { }∨{ } [2,1] [ ]×[ ]×[ ]+ 4
6c O(1)×SO(1)×SO(1) Dih1 Full symmetry of mirrored sphenoid, { }∨( )∨( ) [1,1] [ ]×[ ]+×[ ]+ 2
6d SO(1)×SO(1)×SO(1) C1 Scalene tetrahedron, ( )∨( )∨( )∨( ) [1,1]+ [ ]+×[ ]+×[ ]+ 1

4D

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Continuous symmetries in 4-space can be classified as products of orthogonal groups O(4) or special orthogonal groups SO(4) = O(4)/O(1), along with semidirect products with half turns, C2.

# Rank 4 groups Other names Example geometry Example finite subgroup
Bracket Product Graph Order
1 O(4) Full symmetry of the 3-sphere, , point [4,3,3] 384
1b SO(4) Direct 3-sphere [4,3,3]+ 192
2 O(3)×O(1) Full symmetry of spherinder, ×{ }, segment, { } [4,3,2] [4,3]×[ ] 96
2b SO(3)×O(1) [(4,3)+,2] [4,3]+×[ ] 48
2c SO(3)⋊C2 Direct spherinder [4,3,2]+ ([4,3]×[ ])+ 48
3 O(3)×SO(1) O(3) Full symmetry of hypercone, ∨( ) [4,3,1] [4,3]×[ ]+ 48
3b SO(3)×SO(1) SO(3) Direct hypercone [4,3,1]+ [4,3]+×[ ]+ 24
4 O(2)×O(2)×2! Extended full symmetry of duocylinder, aut(×) [[p,2,p]] 8p2
4b O(2)×O(2) Dih2
Full symmetry of duocylinder, × [p,2,q] [p]×[q] 4pq
4c O(2)×SO(2) Dih×C [p,2,q+] [p]×[q]+ 2pq
4d SO(2)×SO(2) C×C Direct duocylinder [p+,2,q+] [p]+×[q]+ pq
4e O(2)×Dihn Dih×Dihn Full symmetry of circle-n-gon duoprism, ×{n} [p,2,q] [p]×[q] 4pq
4f (O(2)×O(2))/O(1) Dih2
/Dih1
Direct duocylinder [p,2,q]+ ([p]×[q])+ 2pq
4g (O(2)×Dihn)/O(1) C⋊Cn Direct symmetry of circle-n-gon duoprism
4h O(2)×(O(1)×O(1)×2!) Dih×Dih4 Full symmetry of circle-square duoprism, ×{4} [p,2,4] [p]×[4] 16p
4i O(2)×O(1)×O(1) Dih××Dih2 Full symmetry of circle-rectangle duoprism, ×{ }2 [p,2,2] [p]×[ ]×[ ] 8p
4j (O(2)×O(1)×O(1))/O(1) (Dih×Dih2
1
)/O(1)
Direct [p,2,2]+ ([p]×[ ]×[ ])+ 4p
4h SO(2)×O(1)×O(1) C×Dih2
1
[p+,2,2] [p]+×[ ]×[ ] 4p
4i SO(2)×(O(1)×O(1))/O(1) C×C2 Direct [p+,2,2+] [p]+×[2]+ 2p
5 O(2)×O(1)×SO(1) Dih×Dih1 Full symmetry of cylinder pyramid, (×{ })∨( ) [p,2,1] [p]×[ ]×[ ]+ 4p
5b SO(2)×O(1)×SO(1) C×Dih1 [p+,2,1] [p]+×[ ]×[ ]+ 2p
5c (SO(2)⋊C2)×SO(1) C⋊C2 Direct cylinder pyramid [p,2,1]+ [p,2]+×[ ]+ 4p
6 O(2)×(SO(1)×SO(1)×2!) Dih×Dih1 Extended full symmetry of circle-segment pyramid, ∨{ } [p,[1,1]] [p]×[ ]+×[ ]+ 4p
6b O(2)×SO(1)×SO(1) Dih Full symmetry of circle-segment pyramid, ∨( )∨( ) [p,1,1] [p]×[ ]+×[ ]+ 2p
6c SO(2)×SO(1)×SO(1) C Direct [p,1,1]+ [p]+×[ ]+×[ ]+ p
7 (O(1)×O(1)×O(1)×O(1))×4! 4-cube, {4,3,3} [4,3,3] 384
7b O(1)×O(1)×(O(1)×O(1)×2!) Cubic prism, {4,3}×{ } [4,3,2] [4,3]×[ ] 96
7c (O(1)×O(1)×2!)×(O(1)×O(1)×2!) Dih4
2
Duoprism, {4}×{4} [4,2,4] [4]×[4] 64
7d O(1)×O(1)×O(1)×O(1) Dih4
1
4-orthotope, { }4 [2,2,2] [ ]×[ ]×[ ]×[ ] 16
7e (O(1)×O(1)×O(1)×O(1))/O(1) Dih4
1
/Dih1
Direct [2,2,2]+ ([ ]×[ ]×[ ]×[ ])+ 8
8 (O(1)×O(1)×O(1)×3!)×SO(1) cube pyramid, {4,3}∨( ) [4,3,1] [4,3]×[ ]+ 48
8b O(1)×O(1)×O(1)×SO(1) Dih3
1
cuboid pyramid, { }3∨( ) [2,2,1] [ ]×[ ]×[ ]×[ ]+ 8
8c (O(1)×O(1)×O(1)×SO(1))/O(1) Dih3
1
/Dih1
Direct [2,2,1]+ ([ ]×[ ]×[ ])+×[ ]+ 4
9 (O(1)×O(1)×2!)×(SO(1)×SO(1)×2!)) Dih4×Dih1 square-segment pyramid, {4}∨{ } [[2],[1,1]] [4]×[ ]×[ ]+ 16
9b (O(1)×O(1)×2!)×SO(1)×SO(1) Dih4 square-segment pyramid, {4}∨( )∨( ) [[2],1,1] [4]×[ ]+×[ ]+ 8
9c O(1)×O(1)×SO(1)×SO(1) Dih2 rectangle-segment pyramid, { }2∨( )∨( ) [2,1,1] [ ]×[ ]×[ ]+×[ ]+ 4
9d (O(1)×O(1)×SO(1)×SO(1))/O(1) C2 Direct, rectangle-segment pyramid [2,1,1]+ ([ ]×[ ])+×[ ]+×[ ]+ 2
10 O(1)×SO(1)×SO(1)×SO(1) Dih1 bilateral symmetry, { } [1,1,1] [ ]×[ ]+×[ ]+×[ ]+ 2
10b SO(1)×SO(1)×SO(1)×SO(1) C1 No symmetry [1,1,1]+ [ ]+×[ ]+×[ ]+×[ ]+ 1

5D

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Continuous symmetries in 5-space can be classified as products of orthogonal groups O(5) or special orthogonal groups SO(5) = O(5)/O(1).

# Rank 5 groups Other names Example geometry Example finite subgroup
Bracket Product Graph Order
1 O(5) Full symmetry of the 4-sphere, , point [4,3,3,3] 3840
1b SO(5) Direct 4-sphere [4,3,3,3]+ 1920
2 O(4)×O(1) Full symmetry of 3-sphere-segment prism, ×{ }, segment, { } [4,3,3,2] [4,3,3]×[ ] 768
2b SO(4)×O(1) [(4,3,3)+,2] [4,3,3]+×[ ] 384
2c SO(4)⋊C2 Direct 3-sphere-segment prism [4,3,3,2]+ ([4,3,3]×[ ])+ 384
3 O(4)×SO(1) O(4) Full symmetry of 3-sphere cone, ∨( ) [4,3,3,1] [4,3,3]×[ ]+ 384
3b SO(4)×SO(1) SO(4) Direct 3-sphere cone [4,3,3,1]+ [4,3,3]+×[ ]+ 192
4 O(3)×O(1)×SO(1) sphere-segment pyramid, ∨{ } [4,3,2,1] [4,3]×[ ]×[ ]+ 96
4b (O(3)×O(1)×SO(1))/O(1) direct sphere-segment pyramid [4,3,2,1]+ [4,3,2]+×[ ]+ 48
4c O(3)×SO(1)×SO(1) sphere-segment pyramid [4,3,1,1] [4,3]×[ ]+×[ ]+ 48
4d (O(3)×SO(1)×SO(1))/O(1) sphere-segment pyramid [4,3,1,1]+ [4,3]+×[ ]+×[ ]+ 24
5 O(3)×O(2) sphere-circle prism, × [4,3,2,p] [4,3]×[p] 96p
5b (O(3)×O(2))/O(1) Direct sphere-circle prism [4,3,2,p]+ ([4,3]×[p])+ 48p
6 O(3)×(O(1)×O(1)×2!) sphere-square prism, ×{4} [4,3,2,4] [4,3]×[4] 384
6b O(3)×O(1)×O(1) sphere-segment-segment prism, ×{ }×{ } [4,3,2,2] [4,3]×[ ]×[ ] 192
6c O(3)×O(1)×SO(1) (sphere-segment prism) pyramid, ×{ }∨( ) [4,3,2,1] [4,3]×[ ]×[ ]+ 96
6d O(3)×(SO(1)×SO(1)×2!) sphere-segment pyramid, ∨{ } [4,3,1,2] [4,3]×[ ]+×[ ] 96
6e O(3)×SO(1)×SO(1) sphere-point-point pyramid, ∨( )∨( ) [4,3,1,1] [4,3]×[ ]+×[ ]+ 48
7 O(2)×O(2)×O(1) circle-circle-segment prism, aut(×)×{ } [[p,2,p],2] [p]×[p]×[ ] 16p2
7b (O(2)×O(2)×2!)×O(1) circle-circle-segment prism, ××{ } [p,2,q,2] [p]×[q]×[ ] 8pq
7c ((O(2)×O(2)×2!)×O(1))/O(1) Direct circle-circle-segment prism [p,2,q,2]+ ([p]×[q]×[ ])+ 4pq
8 (O(2)×O(2)×2!)×SO(1) circle-circle pyramid, aut() [[p,2,p],1] [p]×[p]×[ ]+ 8p2
8b O(2)×O(2)×SO(1) circle-circle pyramid, [p,2,q,1] [p]×[q]×[ ]+ 4pq
9c (O(2)×O(2)×SO(1))/O(1) Direct circle-circle pyramid [p,2,q,1]+ ([p]×[q])+×[ ]+ 2pq
9 O(2)×O(1)×O(1)×SO(1) (circle-segment prism)-segment pyramid, (×{ })∨{ } [p,2,2,1] [p]×[ ]×[ ]×[ ]+ 8p
9b (O(2)×O(1)×O(1)×SO(1))/O(1) direct (circle-segment prism)-segment pyramid [p,2,2,1]+ ([p]×[ ]×[ ])+×[ ]+ 8p
9c O(2)×O(1)×SO(1)×SO(1) (circle-segment prism)-point-point pyramid, (×{ })∨( )∨( ) [p,2,1,1] [p]×[ ]×[ ]+×[ ]+ 4p
9d (O(2)×O(1)×SO(1)×SO(1))/O(1) Direct (circle-segment prism)-point-point pyramid [p,2,1,1]+ [p,2]+×[ ]+×[ ]+ 2p
9e O(2)×SO(1)×SO(1)×SO(1) circle-point-point-point pyramid, ∨( )∨( )∨( ) [p,1,1,1] [p]×[ ]+×[ ]+×[ ]+ 2p
9f (O(2)×SO(1)×SO(1)×SO(1))/O(1) circle-point-point-point pyramid [p,1,1,1]+ [p]+×[ ]+×[ ]+×[ ]+ p
10 (O(1)×O(1)×O(1)×O(1)×O(1))×5! 5-cube, {4,3,3,3} [4,3,3,3] 3840
10b O(1)×O(1)×O(1)×O(1)×O(1) Tesseract prism, {4,3,3}×{ } [4,3,3,2] [4,3,3]×[ ] 768
10c O(1)×O(1)×O(1)×O(1)×O(1) cubic prism prism, {4,3}×{4} [4,3,2,4] [4,3]×[4] 384
10d O(1)×O(1)×O(1)×O(1)×O(1) cubic prism prism, {4,3}×{ }×{ } [4,3,2,2] [4,3]×[ ]×[ ] 192
10e (O(1)×O(1)×2!)×(O(1)×O(1)×2!)×O(1) Dih4
2
Duoprism, {4}×{4}×{ } [4,2,4,2] [4]×[4]×[ ] 128
10f (O(1)×O(1)×2!)×(O(1)×O(1)×2!)×O(1) Dih4
2
Duoprism, {4}×{4}∨{ } [4,2,4,1] [4]×[4]×[ ]+ 64
10g O(1)×O(1)×O(1)×O(1)×O(1) Dih5
1
5-orthotope, { }5 [2,2,2,2] [ ]×[ ]×[ ]×[ ]×[ ] 32
10h (O(1)×O(1)×O(1)×O(1)×O(1))/O(1) Dih5
1
/Dih1
Direct [2,2,2,2]+ ([ ]×[ ]×[ ]×[ ]×[ ])+ 8
11 (O(1)×O(1)×O(1)×O(1)×4!)×SO(1) tesseract pyramid, {4,3,3}∨( ) [4,3,3,1] [4,3,3]×[ ]+ 384
11b O(1)×O(1)×O(1)×O(1)×SO(1) Dih4
1
4-orthotope pyramid, { }4∨( ) [2,2,2,1] [ ]× ]×[ ]×[ ]×[ ]+ 16
11c (O(1)×O(1)×O(1)×O(1)×SO(1))/O(1) Dih4
1
/Dih1
Direct [2,2,2,1]+ ([ ]×[ ]×[ ]×[ ])+×[ ]+ 8
12 O(1)×O(1)×O(1)×SO(1)×SO(1) Dih3 box-segment pyramid, { }3∨( )∨( ) [2,2,1,1] [ ]×[ ]×[ ]×[ ]+×[ ]+ 8
12b (O(1)×(O(1)×O(1)×SO(1)×SO(1))/O(1) C3 Direct, box-segment pyramid [2,2,1,1]+ ([ ]×[ ]×[ ])+×[ ]+×[ ]+ 4
13 O(1)×O(1)×SO(1)×SO(1)×SO(1) Dih2 {2} [1,1,1,1] [ ]×[ ]×[ ]+×[ ]+×[ ]+ 4
13b SO(1)×SO(1)×SO(1)×SO(1)×SO(1) C1 No symmetry [1,1,1,1]+ [ ]+×[ ]+×[ ]+×[ ]+×[ ]+ 1

See also

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