[r-t] Extension
Robin Woolley
robin at robinw.org.uk
Mon Mar 20 06:48:54 UTC 2017
Hi Al,
There are a couple of principles underlying Method Extension, and
everything flows from these.
i) There is a piece of work in the extension if and only if it is in the
parent
ii) Place notation is the way to find extensions.
The first, for example, ensures that a parent only having at most two
blows in any place has extensions with the same property (q.v. Beverley
S). At this point, someone will mention PB/Grandsire but that's an
historic mistake.
These principles lead on to a general set of formulae but these are
moderated by restrictions which are based upon how methods were extended
when the rules were originally formulated.
In short, if an 'extension' of Cambridge S6 did not have the Cambridge
'front-work', would that be Cambridge?
People seem to have got hung up on contractions. In fact, Yorkshire and
Pudsey define their own sequences starting only at eight. The danger
here is of not seeing the wood for the trees.
Some years ago, I opined that Yorkshire S8 was an alternative extension
of Cambridge S6. As usual, someone said I was wrong, but look at the
place notation. Comparing the two, it is as if the place notation has
been pulled apart and extra bits added in the middle. It reminds me of
one of those children's toys in the form of a pair of linked spiralled
wires which have to be pulled apart.
If someone had decided 150 years or so ago that Yorkshire S8 was the
extension of Cambridge S6, then we would accept it now. The restrictions
referred to above only encapsulate a value judgement!
Further, the Cambridge S6, Yorkshire S8 sequence continues with Albanian
S10 and Southwark S12. Pudsey S8 gives Prittlewell S10 and Gartree S12.
A similar sequence on 10 starts with Solihull, then Manitoba S12.
Saskatchewan S12 generates another sequence which starts on 12 bells.
Each new 'name' then extends via the 'Cambridge' idea.
Think, also, of the way York S6 extends all the way to S20
If you take time to write out the place notations, the above becomes
obvious. All these are valid but from a slightly different starting point.
I asked sometime ago for a reminder of why some believe that Ipswich S8
is an extension of Ipwsich S6. There is one, I know, but, when I last
looked, IS8 had four pull dodging on the front. I don't remember this
quality in IS6.
Method Extension is a very simple exercise - but, like most simple
things, is very difficult to write down.
By the way, has anyone a copy of Richard Smith's extension software? He
asked me if I had one at Hull in '15.
Best wishes
Robin
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