Difference between revisions of "Quasicyclic group"

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{{prime-parametrized particular group}}
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==Definition==
 
==Definition==
  

Revision as of 00:32, 15 January 2012

This article is about a family of groups with a parameter that is prime. For any fixed value of the prime, we get a particular group.
View other such prime-parametrized groups

Definition

Let p be a prime number. The p-quasicyclic group is defined in the following equivalent ways:

  • It is the group, under multiplication, of all complex (p^n)^{th} roots of unity for all n.
  • It is the quotient L/\mathbb{Z} where L is the group of all rational numbers that can be expressed with denominator a power of p.
  • It is the direct limit of the chain of groups:

\mathbb{Z}/p\mathbb{Z} \to \mathbb{Z}/p^2\mathbb{Z} \to \dots \to \mathbb{Z}/p^n\mathbb{Z} \to .

where the maps are multiplication by p maps.

The quasicyclic group is Abelian, locally finite, and locally cyclic, any two subgroups of it are comparable, and every subgroup is characteristic.