QuaternionGroup - Maple Help
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GroupTheory

  

QuaternionGroup

  

construct a generalized quaternion group

 

Calling Sequence

Parameters

Description

Examples

Compatibility

Calling Sequence

QuaternionGroup( n )

QuaternionGroup( f )

Parameters

n

-

(optional) an integer greater than or equal to 3.

f

-

(optional) equation of the form form = "permgroup" (default) or form = "fpgroup"

Description

• 

The QuaternionGroup( n ) calling sequence constructs a generalized quaternion group of order 2n, where 3≤n is an integer.

• 

The argument n is optional, and is taken to be equal to 3 by default, so the calling sequence QuaternionGroup() returns a quaternion group of order 8.

• 

The quaternion group is one of the two non-abelian groups of order 8, (the other being the dihedral group of degree 4). It is notable because it is an example of a Hamiltonian group - every one of its subgroups is normal - and it appears as a subgroup of every non-Abelian Hamiltonian group.

• 

The generalized quaternion group is constructed as a permutation group by default.

• 

But, you can pass the option 'form' = "fpgroup" or 'form' = "permgroup" to cause the QuaternionGroup command to return a group of the indicated class.

• 

In the Standard Worksheet interface, you can insert this group into a document or worksheet by using the Group Constructors palette.

Examples

> 

with⁡GroupTheory:

> 

QuaternionGroup⁡

Q

(1)
> 

QuaternionGroup⁡form=permgroup

Q

(2)
> 

QuaternionGroup⁡form=fpgroup

Q

(3)
> 

GroupOrder⁡QuaternionGroup⁡

8

(4)

There are only two non-Abelian groups of order eight.

> 

SearchSmallGroups⁡order=8,abelian=false

8,3,8,4

(5)

One of these is the Quaternion group.

> 

IdentifySmallGroup⁡QuaternionGroup⁡

8,4

(6)

The dihedral group of order 8 (and degree 4) is the other group of order 8. It is not isomorphic to the quaternion group.

> 

AreIsomorphic⁡QuaternionGroup⁡,DihedralGroup⁡4

false

(7)

However, the quaternion and dihedral groups of order eight do have the same character tables.

> 

ctQ≔CharacterTable⁡QuaternionGroup⁡

ctQ≔C1a2a4a4b4c|C|11222X111111X211−1−11X311−11−1X4111−1−1X52−2000

(8)
> 

ctD≔CharacterTable⁡DihedralGroup⁡4

ctD≔C1a2a2b2c4a|C|11222X111111X211−1−11X311−11−1X4111−1−1X52−2000

(9)
> 

EqualEntries⁡GetMatrix⁡ctQ,GetMatrix⁡ctD

true

(10)

(Notice, however, that the quaternion group has a single conjugacy class of involutions, while the dihedral group of order 8 has three conjugacy classes of involutions.)

> 

GraphTheory:-DrawGraph⁡CayleyGraph⁡QuaternionGroup⁡

> 

DrawCayleyTable⁡QuaternionGroup⁡

> 

DrawSubgroupLattice⁡QuaternionGroup⁡

The quaternion group is an example of a Hamiltonian group - every one of its subgroups is normal. This is evident from the subgroup lattice diagram above; alternatively, Hamiltonicity can be demonstrated, as follows.

> 

andmap⁡IsNormal,convert⁡SubgroupLattice⁡QuaternionGroup⁡,list,QuaternionGroup⁡

true

(11)

Like the dihedral group of order 8, the quaternion group is an extra-special 2-group.

> 

map⁡GroupOrder,Centre,DerivedSubgroup,FrattiniSubgroup⁡QuaternionGroup⁡

2,2,2

(12)
> 

map⁡op∘Generators,Centre,DerivedSubgroup,FrattiniSubgroup⁡QuaternionGroup⁡

1,32,45,86,7

(13)

The quaternion group of order 8 is Hamiltonian, but generalized quaternion groups of larger order are not.

> 

IsHamiltonian⁡QuaternionGroup⁡

true

(14)
> 

IsHamiltonian⁡QuaternionGroup⁡5

false

(15)

Quaternion groups do not have perfect order classes.

> 

IsPerfectOrderClassesGroup⁡QuaternionGroup⁡4

false

(16)

Compatibility

• 

The GroupTheory[QuaternionGroup] command was introduced in Maple 17.

• 

For more information on Maple 17 changes, see Updates in Maple 17.

See Also

GroupTheory[AreIsomorphic]

GroupTheory[DicyclicGroup]

GroupTheory[DihedralGroup]

GroupTheory[GroupOrder]

https://en.wikipedia.org/wiki/Quaternion_group