[r-t] Complexity of extents

Alexander Holroyd holroyd at math.ubc.ca
Fri Jun 28 13:24:06 UTC 2013

I vaguely remember that PABS had an extent of the principle with calls 3 and 5 that exploited an unusual kind of 
symmetry.  (Perhaps he would care to remind us).

On Mon, 24 Jun 2013, Richard Smith wrote:

> Andrew Johnson wrote:
>>> From: Richard Smith <richard at ex-parrot.com>
>>> But when I try to get an extent with rotational symmetry, it
>>> feels like I'm fighting against the symmetry rather than
>>> utilising it.
>> It's not an extent, but for rotational symmetry were
>> you thinking of compositions such as Ander's 5024 Bristol S.
>> Major?
> Not really.  I think the difference between an extent an eighth-extent (a 
> peal of major) is significant.  I was thinking more of extents on four, five 
> or six.  I can't say I've ever tried to produce a rotationally symmetric 
> peal of major.
> Naïvely you wouldn't necessarily expect a rotationally symmetric extent to 
> be any harder to produce than a palindromic one.  Both symmetries constrain 
> half of the rows.  But, at least in my experience, a rotationally symmetric 
> extent (that's not also palindromic) feels a much tougher proposition than a 
> palindromic one.
> _______________________________________________
> ringing-theory mailing list
> ringing-theory at bellringers.net
> http://bellringers.net/mailman/listinfo/ringing-theory_bellringers.net

More information about the ringing-theory mailing list