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Dear Gap Forum,

Stefan Kohl wrote

In this example, the character table can be fetched from the

library viagap> tbl:= CharTable( "3.Suz.2" ); CharTable( "3.Suz.2" )I just want to make a small, rather technical remark here :

The function `CharTable' is only defined in GAP 3,

in GAP 4 it is called `CharacterTable' (and is, by the

way, not yet documented in GAP 4 beta 5).

Changes of variable names such as this one are listed in Section

``Changed Variable Names'' of Chapter ``Migrating to GAP 4'' in

the GAP 4 Tutorial.

Concerning the examples for semidirect product

constructions also given by Thomas Breuer :

There is no function `PermGroup' to convert

a given group to a permutation group in GAP 4,

this also works only in GAP 3 up to now.

Section ``Isomorphisms vs. Isomorphic Structures'' of the same

chapter in the GAP 4 Tutorial describes how to get different

representations of groups.

For example `IsomorphismPermGroup' can be used to construct an

isomorphism to a permutation group, and this permutation group

can then be accessed with `Image'.

In GAP 4, there is also no method for

`ExtraspecialGroup(IsPermGroup, ...)',

as far as I have seen, this works only for the

default category `IsPcGroup'.

Also GAP 3 did not provide the possibility to get a permutation

group as result of a call to `ExtraspecialGroup'.

As in the situation above, one can use `PermGroup' (in GAP 3)

or `IsomorphismPermGroup' and `Image' (in GAP 4)

--although it is probably not a good idea to use a permutation

representation when dealing with an extraspecial group.

Kind regards,

Thomas Breuer

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