[GAP Forum] Documentation understanding of unary `Subgroup`

[Gaurav Dhingra]

Hi GAP forum members,

For the unary version of `Subgroup`, i am using it like this:
```
gap> g:=Group((1,2,3,4),(1,2));;
gap> f:=Subgroup(g)
<group>
```

Reading in the documentation it says:
 > The  unary  version of Subgroup creates a (shell) subgroup that does 
not even know generators but can be used to collect information about a 
particular subgroup over time.

I don't understand what this means, can someone explain this? In 
particular the statement "collect information over time", sounds very 
unknown to me from GAP user perspective.


Thanks
Gaurav