This file contains the replacement text for the consolidated
neighbour-theory section in docs/gate-1-distinct-phenomenon.adoc.
After applying, the consolidated doc points to the per-neighbour
adjacency directory rather than duplicating the analysis.
In docs/gate-1-distinct-phenomenon.adoc, the entire section
titled "Neighbouring theories that already do 'fibers of
non-injective maps'" — including all five sub-sections (Galois,
quotients, IFC, refinements, provenance). This section is
superseded by the per-neighbour adjacency directory.
== Neighbouring theories
Per-neighbour distinctness comparisons live in
`docs/adjacency/`. Each neighbour gets its own file with an
explicit (narrow) distinctness claim, which structural argument
(truncation, 2-cell, multiplicity) is load-bearing, formal
exhibit pointers, and explicit retraction conditions.
The two argument families that emerged from working through the
neighbours individually are framed in `docs/adjacency/README.adoc`.
Briefly:
* *Truncation arguments* (refinement, IFC, provenance, quotients):
echo wins by carrying type-data where the neighbour carries
propositional or single-witness content. Formal certificate is
the family of `echo-not-prop` lemmas in
`proofs/agda/examples/`.
* *2-cell arguments* (quotients, Galois): echo wins because the
natural 2-cell in the neighbour's framework is
Σ-over-preimages-shaped. Formal certificates are
`EchoVsQuotient.Sophisticated.equalizer→echo-pair` and
`EchoVsGalois.Sophisticated.meet→echo-intersection`.
Two neighbours not in the original five-neighbour list are now
also covered:
* *Modal type theories* (QTT, Reed-Pfenning, etc.) — co-extensive
with echo on bare echo in QTT-class systems; recipe-level
distinctness is an open question. See
`docs/adjacency/modal-type-theories.adoc`.
* *HoTT homotopy fibers* — echo IS the homotopy fiber; the win
is over the propositional truncation modality, not over fibers
themselves. See `docs/adjacency/hott-fibers.adoc`.
The files:
[cols="2,3", options="header"]
|===
| File | Neighbour
| `docs/adjacency/quotients.adoc` | Quotient types / setoid quotients
| `docs/adjacency/galois-connections.adoc` | Galois connections / abstract interpretation
| `docs/adjacency/refinement-types.adoc` | Refinement types
| `docs/adjacency/information-flow.adoc` | IFC (Goguen-Meseguer lineage)
| `docs/adjacency/provenance.adoc` | Provenance / data lineage
| `docs/adjacency/modal-type-theories.adoc` | QTT, Reed-Pfenning, adjoint modalities
| `docs/adjacency/hott-fibers.adoc` | HoTT homotopy fibers
|===
The honest summary: gate #1 has a strong consolidated argument
plus formalised obstructions against the two strongest neighbours
(quotients, Galois) plus formalised truncation wins on three
domains (tropical, epistemic, linear). The remaining neighbours
have framed but only-partially-formalised distinctness claims;
see each file for what's done and what's open.The consolidated section gave the impression of five symmetric comparisons, when in fact two neighbours had hundreds of lines of formalised obstruction work and three had a paragraph each. The per-neighbour split makes the gaps visible (refinement, IFC, provenance need their own dedicated formalisation work; modal type theories and HoTT fibers need to be acknowledged honestly).
The replacement also enforces the narrow claim discipline: the consolidated section’s framings of refinement types and HoTT fibers in particular were broader than the formal exhibits support. The per-neighbour notes state the narrow defensible claims and acknowledge the tied/coincident cases explicitly.
After the surgery:
-
roadmap-gates.adocalready specifiesdocs/adjacency/as the gate-1 artefact path; the directory now exists. Noroadmap-gates.adocchange required. -
next-questions.adocQC.1 (which proposed the split and asked whether to do it) is closed by the existence of this directory. The QC.1 entry should be updated innext-questions.adocto reflect closure. -
The
gate-1-handoff.adoccross-lane observations remain as evidence of how the split was reached; no edit needed.