# [r-t] Doubles 240s

Alexander Holroyd holroyd at math.ubc.ca
Fri Mar 20 15:37:24 UTC 2015

```Why on earth is any of this relevant?  If the same row is rung twice, then
the transformation from one to the other is the identity permutation.  In
the context of the recent discussions on this list, people have been
referring to this as "the identity change" and "the null change".  End of
story.

If John C, Richard J, Martin or anyone else does not like this term, they
are free do an automatic text replace on the archives, replacing "null
change" and "identity change" with "transition from one row to an
identical row" or whatever they please.

Then perhaps we could get back to productive discussion?

On Fri, 20 Mar 2015, Martin Bright wrote:

> On 20 March 2015 at 11:10, James White <jw_home at ntlworld.com> wrote:
>> Richard Johnston wrote:
>>
>>>> I agree with JEC that call changes don't involve the identity change,
>>>> and nor would full-pull method ringing (which I would support).
>>
>> What?  Am I missing something here?  When we repeat a row, we have rung the
>> identity change.
>> Every other change in full-pull method ringing is the identity change.
>
> I'm (perhaps surprisingly) with JEC on this one.  I think call changes
> consists of ringing the same row lots of times (no changes involved),
> followed by a change, followed by ringing a new row lots of times, and
> so on.  I reckon that, if you compare two performances of call changes
> which differ only in the number of times one of the rows was rung,
> then most people would say you're rung the same sequence of changes.
>
> Similarly I don't think whole-pull Stedman is a different method from
> normal Stedman.  It's the same method, with the same changes, but
> performed in a different way (i.e. with each row rung twice).
>
> A null change in a method, like a 123456 call in Minor, is a different
> beast, and I would count it as a change.  It's really a feature of the
> method or composition and not a feature of the way the method is
> performed.
>
> OK, back to lurking.
>
> Martin
>
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```