# [r-t] Definitions so far

Don Morrison dfm at ringing.org
Tue Jan 20 21:36:46 UTC 2015

```Thanks for the prompt reply. Here are some easy re-replies; some
of the other points I'm going to have to digest more carefully

On Tue, Jan 20, 2015 at 4:00 PM, Richard Smith <richard at ex-parrot.com> wrote:

If you, who has ready opportunities to ring at St Edward King and
Martyr, are not worried about psychoacoustics, I'm sure not going to.

>>> For example, in Minimus the single change that swaps the bells
>>> in seconds and thirds place is denoted '14', as places are
>>> made in first and fourths place.  Bell symbols are used for
>>> places above ninths place.

Just noticed something I missed the first time around: would it not
be better to say "bell symbols" all the way around, rather than
thinking numbers for <= 9 and symbols for > 9?

> The place notation of a block needs separators, but here I'm defining the
> place notation of a change.

Oops, sorry, missed that nicety!

> Let me have a go at reformulating these two definitions.
>
> 1.  A /block/ is a finite sequence of one or more rows, listed
> in the order they are to rung, together optionally with a
> change referred to as its /block-end change/.

I think "to be rung"?

> 2.  A block may be divided into /sub-blocks/ whose rows are a
> sequence of contiguous rows from the parent block.

This seems to be saying we partition a block into sub-blocks, rather
than simply extracting a sub-block out of a block. It's not clear
that there's anything wrong with that, it's just a little surprising.

I think I might phrase it something more like "a sub-block of a block,
the parent block, is itself a block whose rows are a sequence of
contiguous rows from the parent block". Either that, or explicitly
state that the sub-block, too, must contain one or more rows. I
realize that immediately after the preceding sentence you do say "a
sub-block is a block" but that sounds more like it's being stated as a
consequence of the definition, rather than as another clause of the
definition.

> A
> sub-block is a block.  If the sub-block's rows do not include
> the last row of the parent block, then its block-end change is
> the change describing the progression from the last row of the
> sub-block to the first row not included in the block.
> Otherwise the sub-block's block-end change is the block-end
> change of the parent block, if it has one.
>
> 3.  A block without a block-end change is called a /terminal
> block/, and a block with one, a /non-terminal block/.

I think I'd exchange 2 and 3: that is, define all of block, terminal
block and non-terminal block before starting to worry about
sub-blocks.

--
Don Morrison <dfm at ringing.org>
"After all these years I have observed that beauty, like happiness,
is frequent. A day does not pass when we are not, for an instant,