Group of prime power order: Difference between revisions

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* [[Group whose order has at most two prime factors]]
* [[Group whose order has at most two prime factors]]


==Classification==
==Distribution of orders==
 
{{further|[[Classification of groups of prime power order]]}}


===Groups of prime order===
===Groups of prime order===
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For the order a cube of a prime, there are three Abelian possibilities (corresponding to the three possible unordered partitions of 3). There are two non-Abelian possibilities, the [[group of prime-cubed order:U3p|group of unipotent matrices of order 3 over the prime field]] and the semidirect product of the cyclic group of order <math>p^2</math> by a cyclic group of order <math>p</math>.
For the order a cube of a prime, there are three Abelian possibilities (corresponding to the three possible unordered partitions of 3). There are two non-Abelian possibilities, the [[group of prime-cubed order:U3p|group of unipotent matrices of order 3 over the prime field]] and the semidirect product of the cyclic group of order <math>p^2</math> by a cyclic group of order <math>p</math>.
===For higher orders===
The number of groups of order <math>16 = 2^4</math> is 14. For an odd prime <math>p</math>, the number of groups of order <math>p^4</math> is 15.
For higher powers of the prime, the number of groups of prime power order depends on the prime (in general, the larger the prime, the greater the number of groups).

Revision as of 16:58, 28 March 2008

The article defines a property of groups, where the definition may be in terms of a particular prime that serves as parameter
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This article defines a property that can be evaluated for finite groups (and hence, a particular kind of group property)
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Definition

A group of prime power order is defined as a finite group whose order is a power of a prime.

Relation with other properties

Weaker properties

Distribution of orders

Groups of prime order

For every prime p, there is only one group of order p, viz the cyclic group of p elements.

Groups of prime-squared order

Any group whose order is the square of a prime must be Abelian. For full proof, refer: Prime squared is Abelianness-forcing

Hence there are two possibilities for such a group: the cyclic group of order p2 and the elementary Abelian group of order p2.

Groups of prime-cubed order

For the order a cube of a prime, there are three Abelian possibilities (corresponding to the three possible unordered partitions of 3). There are two non-Abelian possibilities, the group of unipotent matrices of order 3 over the prime field and the semidirect product of the cyclic group of order p2 by a cyclic group of order p.

For higher orders

The number of groups of order 16=24 is 14. For an odd prime p, the number of groups of order p4 is 15.

For higher powers of the prime, the number of groups of prime power order depends on the prime (in general, the larger the prime, the greater the number of groups).