[r-t] Method classification question

Andrew Johnson andrew_johnson at uk.ibm.com
Fri Jun 2 12:34:43 UTC 2017

> From: Ben 
> >Andrew Johnson wrote:
> >34.45,4
> >Lead-end 3124685079
> >6 leads, 24 change round block
> >>From a construction point of view:
> >Front 3 bells plain hunt
> >4 is fixed
> >Back 6 treble bob
> I don't understand this. How do the front 3 bells plain hunt? Surely
> both 45 and 4 in the place notation imply both 145 and 14 
> respectively, which cause nothing like a plain hunt? To my mind, 
> there are two leads at every (even) stage and the back bells do not 
> treble bob either.
> Ben Newsam_______________________________________________
The comma in the place notation is significant
expands to
See http://www.ringing.org/methods/
"More generally the comma operator is an unfolding operation for notating 
palindromes: the changes before the comma, save the last, are repeated in 
reverse order; and similarly those after the comma, the results of the two 
unfolding operations being concatenated. The place notation may contain at 
most one comma."

There are some other conventions:
"Compound place notation is a series of pieces of place notation separated 
by commas. Each piece may start with an ampersand (&), in which case it 
represents a symmetrical sequence of changes: for example, the two strings 
&-2-3-4,5 and -2-3-4-3-2-5 are equivalent."

"In a method where the place notation is symmetrical around the half way 
point only half of the lead and the lead end is recorded. So Shipway Place le 125 may be expanded to le 125 As it 
is symmetrical about last '5'. To expand it you omit the last term and 
work backwards through the notation and add the lead end. Methods 
symmetrical in this way are known as 'Palindromic'."

"If you prefer, you can show the reflecting portion using the ‘&' 
character, and separate out the lead end place notation using the ‘+' 
Abel also accepts Central Council method groups, which allows you to 
specify Plain Bob Minor as:
    a &x1x1x1

"Reversal statements:
Many (most) methods and principles have place notation symmetry about the 
middle of a block of changes. A shorthand way of representing a block that 
is the reverse of another block of place notation is to use the reversal 
operator '~. Note this is not the same as the reversal operator of the 
MicroSiril method libraries, where the last place (at the half lead) is 
not repeated in the reversal, and the whole expansion includes the forward 
as well as the reversed sequence or places. Eril just provides the 
reversal of another block via the reversal operator. Example:

HalfLeadOfKent = 34-34.16-12-16-12-;

LeadOfKent = HalfLeadOfKent + 16 + ~HalfLeadOfKent + 16;

Andrew Johnson


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