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Well, let's find out what Don actually thinks with a direct
question.<br>
<br>
Marple D6 is &x34x4x2x1.34x34.1,1.<br>
<br>
It has four decision compliant extensions (RAS):<br>
<br>
2DE/2FG -34-4-2-1.34-34.1.56-56.1,2 (8 [2] 60)<br>
2DE/5FG -34-4-2-1.34-34.1.34-34.1,2 (8 [2] 60)<br>
2BC/2FG -34-4-256-6.34-34.1.56-56.1,2 (8 [2] 60)<br>
2BC/5FG -34-4-256-6.34-34.1.34-34.1,2 (8 [2] 60)<br>
<br>
Don said he preferred the 56x56 extension of Kent to, inter alia,
the 34x34.1.56x56 or the 56x56.1.56x56. These, on symmetry grounds,
are exactly the extensions below the treble in these four versions.<br>
<br>
[The extensions above are the Kent/York and Cambridge versions)<br>
<br>
In order to fully understand your position, can you 'criticise' - in
the sense of 'To evaluate (something), and judge its merits and
faults' rather than 'find fault with' these extensions?<br>
<br>
The first question which arises to me is, given these are the only
compliant extensions, would you say that Marple is inextensible?
(Yes or no would do very well here!) Why?<br>
<br>
b.t.w., when you mention the 4-colour problem, what was the context
of this? As I recall, a computer was used to check a large number of
situations but this had already been reduced to c2000 from infinity
by using mathematics.<br>
<br>
There are some hard problems. Some are theoretically hard like
Quantum Theory. Others, like extension, are easy conceptually but it
is the size of the problem which makes them hard.<br>
<br>
On another point, aren't we being sidetracked by difficult cases
such as Bristol. If we haven't sorted the easy ones, then it makes
no sense to tackle the odd-ball ones. We must walk before we can
run.<br>
<br>
I seem to remember something from 40-odd years ago, and it has been
repeated since, that Bristol 4n is a different sequence to Bristol
(4n+2) Perhaps it's true!<br>
<br>
R.<br>
<br>
<br>
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