[GAP Forum] "(C4 x C2) : C2"

[Ken W Smith]

Hi Nilo,
	Both groups are semidirect products of a normal subgroup isomorphic to 
C4 x C2 with a subgroup of order 2.

	(More explicitly, according to some notes of mine, group [16,3] is 
generated by elements x, y, z where x has order 4, y and z have order 
2, x and y commute (thus <x,y> = C4 x C2), y and z commute and zxz=xy.  
Group [16,13] is generated by x, y, z with orders 4, 2, 2, respectively 
where xy=yx, xz=zx, zyz=x^2y.)

ken
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On Feb 10, 2006, at 4:11 AM, Nilo de Roock wrote:

> Hello GAP Forum,
>
> Could someone please explain why AllGroups(16)[3] and
> AllGroups(16)[13] both return "(C4 x C2) : C2" on the function
> StructureDescription?
>
> Thanks in advance,
> nilo
>
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---
Ken W. Smith, Professor of Mathematics, Central Michigan University
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