[r-t] Poll on consecutive blows in the same position

[Matthew Frye]

On 29 Dec 2014, at 00:25, Alexander Holroyd <holroyd at math.ubc.ca> wrote:

> On Mon, 29 Dec 2014, Matthew Frye wrote:
> 
>>> how is a dixonoid not a finite sequence of place notations?
>> 
>> If differs in conception and (usual) description. Dixon's Bob would usually be described by a set of rules, not a sequence of place notation.
> 
> I really don't understand the distinction.  A sequence of place notations can be described in many different ways, but it is still the same sequence.
> 
> Perhaps the related concept of composition would be illuminating here. The standard 3-part extent of Cmabridge minor can be described in many different ways, among them: Wrong Home Wrong ; 3 5 3 ; pp-p-pp-pp. Perhaps the first is "observation-based", etc.  But they are all the same composition, surely?  A band whose conductor who thinks of it in the observation-based way is surely not ringing a different extent from the others?

Counter-example: You can ring a touch of Single Court Minor, you can also ring a touch of Original with appropriate (standard 4ths place) bobs so you ring exactly the same rows. Have two bands who ring those things rung the same method? Of course they haven't. This isn't even a contrived example, I once rang the Original version of this touch before I had learnt Single Court as its own method (we as a band weren't very good at branching out into such methods at that time, but we could do Original. We have since learnt and rung touches of Single Court).

The description sets the two things apart, even if you have rung the same changes.

>> I would define lead as a set sequence of place notation (possibly limited by certain criteria currently under discussion), a lead-based method would be a method obtained by ringing a certain lead (repeatedly) until a suitable end-point, or until there is some form of call/change of method.
> 
> Again, it seems that under that description either includes everything of does not include lots of standard things, depending on how the ambiguities are resolved.  If "(repetaedly)" allows ringing a lead only once, then dixonoids are included.  If not, then compositions of spliced in which only one lead of a method appears are no lead-based.

We decided previously that single-lead methods should be allowed, so "(repeatedly)" definitely does allow ringing a lead once (I was trying to convey as much by putting it in brackets). I see no problem in *allowing* a plain course of Dixon's to be defined by its static place notation, I just think that's a crap way to describe it.

As I see it you have three problems with defining it that way:
A) You've only defined one course, the other courses generally will have different place notations.
B) You've described the method in a way other than how the band are (probably) thinking about it.
C) You've described the method in a way that is not the simplest way to describe it.

None of those three things are or should be prohibited (indeed B & C are often at odds with each other), but they are probably all best avoided, especially when you have a much better description so easily available to you. Actually A) is quite a big problem - are the different courses different methods? Do they need different names and to be defined separately? If not, do you apply the rules (whatever they may be) on just the course you have defined or on all the courses you could define?

In summary:

> Why not just define a method to be a finite sequence of place notations?


Because that's just not how I would like Dixon's to be defined!


If what you are actually worried about is two bits of ringing having two separate, and sometimes quite different, descriptions, I would suggest you revisit much of the earlier correspondence (particularly on divisible leads) where we discussed at length when and whether we could limit this ambiguity/degeneracy of description. As I recall, it was not in the least bit successful and I think we now *must* accept multiple descriptions for the same set of changes.

There is, of course, still the tricky problem of whether (and how) the rules can or should be harmonised across different descriptions...

MF