[r-t] Terminology question

Joe Norton super.joey.norton at gmail.com
Tue Aug 25 10:42:56 BST 2020

Ah ha! Thank you, very useful.

On Mon, 24 Aug 2020 at 21:11, Andrew Johnson <andrew_johnson at uk.ibm.com>
wrote:

> > From: Joe Norton
> > I may be about to ask a stupid question or two, but please humour me...
> >
> > Given some block, A. A is some method or block or other ordered set
> > of changes on a given number of bells. It could be anything.
> >
> > If we reflect A about its midpoint (front to back) then the block
> > produced is called "Reverse A". I think I'm still on firm ground.
> >
> > First question:
> > If we make "Backwards A", as in last change first and first change
> > last etc, what is that called as an operation? I'm assuming it's not
> > called reversal, since that is the process of producing "Reverse A" as
> above.
> >
> > Second question:
> > In terms of naming, should A and "Backwards A" be related in any
> > way? This does not usually become an issue seeing as the vast
> > majority of common methods are palindromic. Methods like Polebrook
> > Bob Doubles (5.1.5.3.125.3.125.1.5.125) and Cotterstock Bob Doubles
> > (5.1.125.3.125.3.5.1.5.125) would suggest not but I wondered if
> > there have been any naming rules since then.
> >
> > Thank you and sorry for asking daft questions!
> >
> > Joe._____
> See Martin Bright's paper about symmetries:
> http://www.boojum.org.uk/ringing/symmetry.pdf
> using 'vertical reflection' and
>
> https://cccbr.github.io/method_ringing_framework/classification.html#methodsymmetry
>
> Sometimes 'reverse' is used to mean going backwards, but perhaps for
> compositions where it is clear that the method is staying the same,
> but the order of the calls is reversed.
>
> Perhaps 'retrograde' could also be considered as a term.
>
> Andrew Johnson
>
>
>
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>
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