> < ^ Date: Fri, 22 Sep 1995 14:15:00 +0000
> < ^ From: Dmitrii Pasechnik <d.pasechnik@twi.tudelft.nl >
> ^ Subject: Re: QUERY
```Reply-To: GAP Forum <GAP-Forum@Math.RWTH-Aachen.DE>
X-Miles:        GAP Forum article 669 accepted at 22 Sep 95 12:31 +0100
Date:           22 Sep 95 14:32 +0300
```

Dear Colleague,

Of course, the size of higher dihedral group must be larger.

```But :
gap> d2 := DihedralGroup(2); Size(d2);
Group( (1,2), (3,4) )
4

gap> d4 := DihedralGroup(4); Size(d4);
Group( (1,2) )
2
Is here a bug ?
```

Yours, R.M.

```Yes, there is a bug. (two bugs, to be more precisely).
gap> Print(DihedralPermGroup);
function ( n )
local  D, g, h;
if n = 2  then
g := (1,2);
h := (3,4);
D := Group( g, h ); # this should be just D:=Group(g);
else
g := PermList( Concatenation( [ 2 .. n / 2 ], [ 1 ] ) );
h := PermList( Concatenation( [ 1 ], Reversed( [ 2 .. n / 2 ] ) ) );
D := Group( g, h );
# this won't work for n=4, since D_4 cannot be (faithfully)
# represented on 2 points.
fi;
return D;
endgap>
```

Best wishes,
Dima

> < [top]