Nontrivial semidirect product of Z5 and Q8

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Definition

This group of order 40 is a semidirect product Z5⋊Q8, defined by means of the following presentation:

⟨a,i,j∣a5=i4=j4=e,iji−1=j−1,ia=ai,jaj−1=a−1,⟩

GAP implementation

Group ID

This finite group has order 40 and has ID 4 among the groups of order 40 in GAP's SmallGroup library. For context, there are groups of order 40. It can thus be defined using GAP's SmallGroup function as:

SmallGroup(40,4)

For instance, we can use the following assignment in GAP to create the group and name it G:

gap> G := SmallGroup(40,4);

Conversely, to check whether a given group G is in fact the group we want, we can use GAP's IdGroup function:

IdGroup(G) = [40,4]

or just do:

IdGroup(G)

to have GAP output the group ID, that we can then compare to what we want.