[r-t] Definitions so far

[Richard Smith]

I think I'm now happy with the next section of my 
definitions.  These remove the definition of /change 
ringing/ from my last email.  I think the only controversial 
point is my decision to allow a 5001 of Triples as a peal 
length performance.  (This does not necessarily mean it is
allowed as a peal; in fact I don't propose to address that 
point fully.  Hopefully this will become clearer when I move 
on to truth which will be the next section.)

RAS


D.  Definitions concerning change ringing

1.  A /block/ is a sequence of rows where the progression
between rows is defined by changes.  A /sub-block/ of some
block is a sequence of contiguous rows from that block.  It
too is a block.

2.  When a block is a sub-block of some larger block and does
not include the last row of the larger block, it additionally
has a /block-end change/.  This is the change describing the
progression from the last row of the block to the first row
not in the block.  A block without a block-end change is
called a /terminal block/, and a block with one, a
/non-terminal block/.

4.  /Change ringing/ is the practice of ringing without
break a block of rows known as a /performance/.

5.  A performance consists of up to three parts which in order
are:

   (a) optionally an /opening block/ containing rows
   incidental to the main performance;

   (b) the /primary block/ containing the main part of the
   performance; and

   (c) optionally a /closing block/ containing further rows
   that are incidental to the main performance.

Usually the opening block and closing block constists of just
rounds, and referred to as the /opening rounds/ and /closing
rounds/, respectively.  When discussing a performance, it is
normal to ignore the opening and closing blocks and refer just
to the properties of the primary block.

6.  The /length/ of a block is the number of rows it contains.
A non-terminal block of length n will have n changes,
including the block-end change; a terminal block will only
have n-1 changes.  The length of a performance is deemed to be
the length of its primary block.

7.  A performance of length 5000 or more may be described as a
/peal length performance/.  A performance of length 10,000 or
more may be described as a /long length performance/.  A
performance of length 1250 or more may be described as a
/quarter peal length performance/.  Other fractional peal
lengths are defined in a similar manner but are less commonly
used.

8.  A /round block/ is a non-terminal block whose first row is
the same as the row produced by applying the block-end change
to the last row.  Usually the primary block of a performance
will be a round block whose first row is rounds.