Free group:F2: Difference between revisions

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The free group of rank two is a [[SQ-universal group]]. In particular, it has subgroups that are free of every finite rank as well as a free subgroup of countable rank.
The free group of rank two is a [[SQ-universal group]]. In particular, it has subgroups that are free of every finite rank as well as a free subgroup of countable rank.
==Arithmetic functions==
{| class="wikitable" border="1"
! Function !! Value !! Explanation
|-
| [[order of a group|order]] || infinite (countable) ||
|-
| [[exponent of a group|exponent]] || infinite (countable) ||
|-
| [[Fitting length]] || not defined || There is a nontrivial [[nilpotent normal subgroup]].
|}
==Group properties==
{| class="wikitable" border="1"
! Property !! Satisfied !! Explanation !! Comment
|-
| [[dissatisfies property::cyclic group]] || No || ||
|-
| [[dissatisfies property::abelian group]] || No || ||
|-
| [[dissatisfies property::nilpotent group]] || No || ||
|-
| [[dissatisfies property::solvable group]] || No || ||
|-
| [[satisfies property::free group]] || Yes || ||
|-
| [[satisfies property::hypocentral group]] || Yes || ||
|-
| [[satisfies property::hypoabelian group]] || Yes || ||
|-
| [[satisfies property::imperfect group]] || Yes || ||
|}


==GAP implementation==
==GAP implementation==

Revision as of 00:13, 10 September 2009

This article is about a particular group, i.e., a group unique upto isomorphism. View specific information (such as linear representation theory, subgroup structure) about this group
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Definition

The free group of rank two, also written as F2, is defined as the free group on a generating set of size two. 2 is the smallest possible rank for a free non-abelian group (the free groups of rank 0 and 1 are respectively the trivial group and the group of integers).

The free group of rank two is a SQ-universal group. In particular, it has subgroups that are free of every finite rank as well as a free subgroup of countable rank.

Arithmetic functions

Function Value Explanation
order infinite (countable)
exponent infinite (countable)
Fitting length not defined There is a nontrivial nilpotent normal subgroup.

Group properties

Property Satisfied Explanation Comment
cyclic group No
abelian group No
nilpotent group No
solvable group No
free group Yes
hypocentral group Yes
hypoabelian group Yes
imperfect group Yes

GAP implementation

The free group of rank two can be constructed using GAP with the GAP:FreeGroup command:

FreeGroup(2);

Further, the generators can also be referred to. For instance, if we use:

F := FreeGroup(2);

Then the two generators can be referred to as F.1 and F.2.