[r-t] Undifferentials

[Alexander Holroyd]

On Thu, 7 Jul 2011, Graham John wrote:

>>> 34-16-16-36-16-16-16-16-16-14-16-16-

Thanks for this very clear explanation, Graham!

I think this method is a wonderful example, but sadly it looks as if it 
does not lend itself to an extent (with the usual caveat: at least not 
without massacring it to a point where it is barely recognizable). 
Although it divides neatly into whole courses and half courses of plain 
hunt, and the half-courses are compatible with each other, the plain 
course comprises precisely 6 of the 9 plain hunt courses obtained from the 
plain course of plain hunt by rotating 123 and rotating 456.  So far as I 
can see, there will not be a sensible way to include the other 3.

So, the obvious next challenge: can someone find a minor unprinciple that 
yields an extent?  (My earlier email contains a proof that unprinciples do 
not exist on prime stages: doubles,triples...).

Also very interesting would be a nice practical, interesting, major 
example, with a nice practical, interesting peal composition.

Btw, I find this one of the most interesting threads for quite a while - 
good job folks!

Ander