[r-t] Ben Constant's Yorkshire Royal

[Don Morrison]

On Wed, Jan 14, 2009 at 10:12 AM, Mark Davies <mark at snowtiger.net> wrote:
>> How do you handle the case of the amusing 5,090 of Cambridge that was the
>> subject of extended discussion in the RW some years ago
>
> Remind me of that one again?
>
> With compositions round at the snap you can argue that there is no symmetry,
> at the level of the lead anyway. However in practice such compositions can
> often be viewed as false round-blocks, where the first incidence of
> falseness is rounds at the snap, and hence rotation and reflections can be
> applied. Is that what happened here?

Yes. Though possibly not the first instance of falseness being at the
snap -- it may be that there was a single added or substituted to
bring it round before the falseness occurred.

In any case, it would seem difficult to extend the invariant under
rotations and reversals case to this unambiguously, when no one has
actually written down the entire block that is being rotated or
reversed. Perhaps as a worst case, I can imagine instances existing
where the false, parent block is more than twice as long as the peal,
and the two competing compositions don't even share any of the bits of
calling that are preserved.



-- 
Don Morrison <dfm at ringing.org>
"Practice doesn't make perfect, nor is it supposed to.  Practice is
about increasing your repertoire of ways to recover from your
mistakes."                                          -- Joann C Gutin