IsRegular - Maple Help
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GroupTheory

  

IsRegular

  

determine whether a permutation group is regular

  

IsSemiRegular

  

determine whether a permutation group is semi-regular

 

Calling Sequence

Parameters

Description

Examples

Calling Sequence

IsRegular( G, dom )

IsSemiRegular( G, dom )

Parameters

G

-

: PermutationGroup : a permutation group

dom

-

: {set,list}(posint) : (optional) a domain on which G acts

Description

• 

A permutation group  (acting on the set is semi-regular if the stabilizer of any point is trivial. If, in addition,  acts transitively, then it is said to be regular. This means that the action of  is permutation isomorphic  to the action of  on itself by (right) translation.

• 

Every Abelian transitive permutation group is regular.

• 

The IsRegular( G ) command returns true if the permutation group G is regular, and returns false otherwise. The IsSemiRegular( G ) command returns true if the permutation group G is semi-regular, and returns false otherwise. The group G must be an instance of a permutation group.

• 

The dom option can be used to specify the domain on which G acts.

• 

For regularity in the sense of P. Hall, for groups of prime power order, see GroupTheory[IsRegularPGroup].

Examples

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The symmetric group in its natural permutation representation is not regular.

(19)

But there is a regular permutation representation of degree  (the order of the group).

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The quaternion group of order  has a regular representation of degree .

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We construct a diagonal embedding into the direct square.

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This is the diagonal subgroup.

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Frobenius groups are never regular.

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Let's find all the regular groups of degree . First, we create an iterator for all the transitive groups of that degree.

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Create an Array in which to store the transitive group IDs of those that are found to be regular.

Now iterate over the groups and check for regularity.  Since we already know that the groups are transitive, we avoid the redundant transitivity check and test only for semi-regularity.

(31)

See Also

GroupTheory

GroupTheory[CyclicGroup]

GroupTheory[FrobeniusGroup]

GroupTheory[Group]

GroupTheory[IsRegularPGroup]

GroupTheory[IsTransitive]

GroupTheory[Stabilizer]

GroupTheory[SymmetricGroup]

GroupTheory[TransitiveGroup]

Perm

 


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