Holomorph of D8: Difference between revisions
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==Definition== | ==Definition== | ||
This group is defined | This group is defined in the following eqiuvalent ways: | ||
* It is the [[defining ingredient::holomorph of a group|holomorph]] of the [[defining ingredient::dihedral group:D8|dihedral group of order eight]], i.e., the [[semidirect product]] of the dihedral group of order eight and its [[automorphism group]] (which is also isomorphic to the dihedral group of order eight). | |||
* It is the <math>2</math>-[[Sylow subgroup]] of the [[holomorph of a group|holomorph]] of the [[quaternion group]]. | |||
==GAP implementation== | ==GAP implementation== | ||
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<math>S</math> is the group we need. | <math>S</math> is the group we need. | ||
It can also be constructed using a hand-coded GAP function: [[GAP:Holomorph|Holomorph]] | It can also be constructed using a hand-coded GAP function: [[GAP:Holomorph|Holomorph]], with which it becomes: | ||
<tt>Holomorph(DihedralGroup(8))</tt> | |||
Latest revision as of 00:48, 10 February 2010
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
This group is defined in the following eqiuvalent ways:
- It is the holomorph of the dihedral group of order eight, i.e., the semidirect product of the dihedral group of order eight and its automorphism group (which is also isomorphic to the dihedral group of order eight).
- It is the -Sylow subgroup of the holomorph of the quaternion group.
GAP implementation
Group ID
This finite group has order 64 and has ID 134 among the groups of order 64 in GAP's SmallGroup library. For context, there are groups of order 64. It can thus be defined using GAP's SmallGroup function as:
SmallGroup(64,134)
For instance, we can use the following assignment in GAP to create the group and name it :
gap> G := SmallGroup(64,134);
Conversely, to check whether a given group is in fact the group we want, we can use GAP's IdGroup function:
IdGroup(G) = [64,134]
or just do:
IdGroup(G)
to have GAP output the group ID, that we can then compare to what we want.
Alternative descriptions
The group can be constructed using the GAP commands DihedralGroup, AutomorphismGroup, and SemidirectProduct:
gap> G := DihedralGroup(8); <pc group of size 8 with 3 generators> gap> A := AutomorphismGroup(G); <group of size 8 with 3 generators> gap> S := SemidirectProduct(A,G); <pc group with 6 generators>
is the group we need.
It can also be constructed using a hand-coded GAP function: Holomorph, with which it becomes:
Holomorph(DihedralGroup(8))