[r-t] Extension Processes

[Graham John]

On Fri, 26 Jun 2026 at 19:33, Patrick Deakin <PDeakin1998 at hotmail.co.uk> wrote:
> The CCCBR's Framework for Method Ringing details 3 extension processes, found here:
> https://framework.cccbr.org.uk/version2/extensionprocesses.html
> I had heard that Bristol didn't conform to these processes and, sure enough, I can see on CompLib that the accepted extension path is "EP4-2/6:4:1/6:4:1"
> Is there any documentation for this 4th extension process? Are there other as yet unrecognised extension processes?

EP4 represents the next stage in the evolution of Extension Processes.
I developed it to accommodate many existing extension paths that are
clearly valid but are not addressed by EP1–EP3. It is implemented in
Complib both to validate the approach and to provide a visualiser for
all extension paths. However, its formal adoption by the Technical &
Taxonomy Workgroup, and its incorporation into the Framework for
Method Ringing, is still pending. Until then, Complib’s treatment of
EP4 extensions as Accepted Extension Paths remains provisional.

EP4 subsumes all extensions currently handled by EP1 (principles and
little methods) and EP3 (hunters), but does not replace EP2 (extension
by addition of a hunt bell). Its adoption would therefore simplify the
Framework by allowing EP1 and EP3 to be retired.

The core idea of keeping places fixed below a “mode” line and
expanding them above—established in EP1 and EP3—is also fundamental to
EP4. However, instead of dividing the place notation into discrete
segments, EP4 divides it into two overlapping strips which are then
pulled apart and rejoined to form the extension. This provides greater
flexibility while preserving the principle of repeating sections of
place notation. EP4 is also inherently bidirectional, supporting both
stage expansion and contraction.

EP4 can be applied in Single Mode, its simplest form, where places
below a single mode line remain static and those above are expanded.
When the strips do not overlap, this behaves identically to EP1. With
overlapping strips, however, Single Mode can extend large numbers of
hunters using a simpler mechanism than EP3—for example, the extensions
from Glasgow S Major through Clyde to Strathclyde [the band that first
rang Clyde wanted to name it Glasgow S Royal]. Methods currently
extended by EP3 are handled by EP4 in Dual Mode, where the above and
below work are extended independently around their respective mode
lines. A small number of edge cases require Triple Mode, in which the
hunt bell is also extended around its own mode line.

Complib provides a report
(https://complib.org/report?name=extensionreport) listing Accepted
Methods under EP1–EP4, together with non‑conforming paths. The
statistical summary shows that EP1 and EP3 together relate 600 methods
by extension, whereas EP4 (Single, Dual, and Triple Mode) relates 659.
Once EP4 is adopted, I expect that all remaining non‑conforming
methods will be genuinely unrelated.

Examples of extension paths supported by EP4 that are currently
non‑conforming include:
- Bristol S Major to Royal and up
- Extension by a single stage (e.g. Plain Bob, Double Bob, Reverse
Bob, Grandsire, Original, Stedman, Erin)
- Expansion of lead‑little methods (e.g. Penultimus Little)
- Non‑reextendable contractions (e.g. Kent TB Minimus)
- Extensions of Jump methods (complete but not yet live in Complib)

Complib’s visualiser displays grids of all methods related by an
extension process, with flags indicating any former or current rules
broken by any relation. It also shows how the next extension stage is
derived from the place notation via the Show [derivation] button. You
can access the visualiser by clicking the extension notation for a
method, either in the Accepted Extension Path section or in the
Related Methods tab on the method view page. I apologise for the
current bug that causes the visualiser to crash for certain
single‑stage extensions.

I am not aware of any other yet-to-be documented extension processes.

Graham