[r-t] Plain Bob lead heads/ends (was ringing-theory Digest, Vol 89, Issue 9)

[Matthew Frye]

On 9 Feb 2012, at 22:12, edward martin wrote:

> On 9 February 2012 16:52, Matthew Frye <matthew at frye.org.uk> wrote:
>> 
>> On 9 Feb 2012, at 15:49, edward martin wrote:
>>> In even bell methods, if the lead block is symmetrical about the
>>> treble then the lead heads and lead ends must be in plain bob group
>> 
>> Not what you mean, surely? eg King Edward S Minor (Cambridge with 36 half lead) is perfectly symmetrical but first lead end is 156423. What you say is only true if the correct pairs of bells you then identify actually *do* swap, but this is certainly not required.
> 
> Perhaps you actually didn't read what I said: (It was poorly phrased
> but I DID say "because of the half-lead pivot bell  and its specific
> conjugate pairs " ie
> "In even bell methods, if the lead block is symmetrical about the
> treble then the lead heads and lead ends must be in plain bob group
> (ie the 2-3-4-5-6 etc will be in a plain hunt relationship because of
> the half-lead pivot bell  and its specific conjugate pairs )
> On 8 bells these are
> 2 ; 3x4 5x6 7x8
> 4 : 2x6 3x8 5x7  etc"

I very much did read what you said, did you?
I interpret what you wrote as saying that ALL palindromic methods give pb lead ends, BECAUSE they have the correct bells swapping at the half lead. This should be IF they have the correct bells swapping at the half lead THEN they will give pb lead ends.

I think there's a similar confusion RE your twin-hunt triples.

MF