[r-t] Extension question
Mark Davies
mark at snowtiger.net
Tue Jun 28 22:44:46 UTC 2016
Ted writes,
> I am not familiar with all the rules of extension but know only that I
> have often thought they seem very illogical.
The rules codified in "Decision G", which I suppose you are referring
to, are not the only way of imagining how you might extend (and
contract) methods. However they do have some logic to them, for sure.
They express basic ideas about the structure of a method that perhaps
ought to be preserved through extension - for example, its symmetry, the
type of its treble path, and the pattern of place-making in the lead.
However, whenever you have some nice clear logical ideas about
something, and then sit down to try and codify them, mostly you find the
detail all turns out to be disappointingly more complicated than you
expected. "Decision G" is no different. The original drafters of these
rules had some good ideas, I think, but chose to express them very
concisely without much in the way of explanation. The result is
something that's very obtuse, and hard to work with by hand.
We've debated before whether there is indeed any need for a set of
method extension rules, or whether a free-for-all should be given for
bands ringing and naming methods which they consider to be extensions.
My view is that, for a method to be an extension, you ought to be able
to demonstrate a rational algorithm which can construct it from its
parent (or vice versa), and which also produces nice extensions for a
range of other methods. In this milieu, "Decision G" is almost certainly
not the only such algorithm. In fact someone on this list (was it RAS or
Ander?) came up with another promising one a few months back.
> If an extension of a place
> method is not allowed because it introduces dodges then perhaps the
> answer is to consider the extension as the base stage; the dodges will
> be maintained in further extension but lost, due to lack of dodging
> positions, in the contraction. Does that then become acceptable?
Well it's not acceptable under the current "rules" but I have a lot of
sympathy for that viewpoint. A base stage having zero of something, with
the next stages 1, 2, 3 etc of it, seems perfectly reasonable. We have a
good example already in Bristol Surprise - the Major method has no wrong
dodges, the Royal one, Maximus two, etc.
Perhaps this tells us that the Place and Bob classifications aren't
actually terribly useful. I'm not sure anyone would be too sorry to see
them quietly fade away, would they? (But maybe this is only because
plain methods aren't sexy any more - I can imagine an uproar if TB,
Delight and Surprise were similarly merged, and there would be serious
naming conflicts there too).
> Stedman singles has no dodges but they appear nicely at doubles and
> above; does this mean Stedman Doubles is not a legitimate extension
> of Stedman Singles?
Robin Woolley has sent me this response:
"The singles is unrelated decisionwise to all higher stages. Suppose the
p.n. of the Singles (whole 12s) to be 3.3.1.3.1.3.3.1.3.1.3.1. At all
higher stages, 3rds place becomes the back place so this would be
5.5.1.5.1.5.5.1.5.1.5.1 on five bells, etc.
"[These methods are] very false in the plain course and given that it
seems the word 'method' [was] used to mean 'way of generating the
extent', it seems unlikely Fabian would have bothered about it."
One thing he is pointing out here is that the current extension rules
view lead/lie places as different to internal places, so the 3 place
notation in Stedman Singles must be treated as a lie in all extensions.
But on the other hand if you start from Stedman Doubles as the base
method (which as he says is true, so also classified differently under
current regulations) then the 3 pn is an internal place - it must stay
internal, but doesn't have to (say) move up to 5 at Triples.
Again, you can see a bit of logic in this idea that lead/lie is special.
But you can always think of special cases that test what initially
appears to be "globally-sensible" logic.
MBD
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