test,docs: RG110(c)'s adjacency is unobservable by construction

The re-review asked for a third commemoration in the shape-(c) row, so
that "spliced immediately after its trigger" could be told apart from
"appended at the end" -- it had proved an append-at-end variant passed
the whole suite green, the pair alone being too short to distinguish
them.

Attempting it establishes something better than the test requested. On
this day-shape a third commemoration is rubrically impossible. Shape (c)
requires the trigger to lose the day while still being admitted, and a
Class2 trigger can only lose to a I-class day (RG 111(a): one privileged
commemoration) or a II-class Sunday (RG 111(b): one, "scilicet de festo
II classis"). Both caps are one. The third candidate is now offered and
correctly refused, which is the assertion worth having.

So RG 110(c)'s "ante omnes alias commemorationes" half has no reachable
witness in the EF's rubrical space, and the re-review's own finding that
shape (c) never co-occurs with a third commemoration across 8417 years
is a consequence of the rubric rather than an accident of the data. The
append-at-end variant stays indistinguishable from the splice on every
input the engine can construct. Recorded rather than papered over with a
synthetic row proving a shape no rubric permits.

Also drops Record from the "nothing compares commemoration order" note
-- Record.t has no commemorations field at all -- and names, at
privilege_of's own (a) branch, that the Holy Name's Sunday privilege
currently rests on a substring match rather than on RG 17's closing
paragraph, which is its real warrant.

1 files changed, 44 insertions, 1 deletions

diff --git a/test/test_precedence_ef.ml b/test/test_precedence_ef.ml
index 639f64c..ed9a933 100644
--- a/test/test_precedence_ef.ml
+++ b/test/test_precedence_ef.ml
@@ -1031,6 +1031,16 @@ let sixtus =
 let chair_of_st_peter_synth = cand ~rank:V.Class2 "chair-of-st-peter"
 let paul_companion_synth = cand ~rank:V.Class3 ~status:Cel.Commemoration_only "paul"
 
+(* An unrelated third commemoration, sorting AFTER both members of the RG110
+   pair, so that "spliced immediately after its trigger" and "appended at the
+   end" give different answers. Added by the fix-round re-review (G1): with
+   only the pair present the two are indistinguishable, and the re-review
+   proved an append-at-end variant passed the whole suite green. Class3
+   Commemoration_only so it cannot win the day; its slug is deliberately not
+   one {!PE.rg110_companion_slug} recognises. *)
+let unrelated_comm_synth =
+  cand ~rank:V.Class3 ~status:Cel.Commemoration_only "zzz-unrelated-commemoration"
+
 (* Any real Lent/Ember feria's own shape (a Class3, PRIVILEGED, temporal-
    origin candidate) -- {!PE.rg110_companion_slug} does not match this slug,
    so it is a neutral bystander in [admit]'s own normal (pre-RG110) contest,
@@ -1184,7 +1194,40 @@ let admit_cases =
        (loses the day to an ordinary II-class Sunday), Paul rides along \
        AFTER it (RG110(c): \"huic orationi additur altera\")",
       cand ~rank:V.Class2 "ef-some-other-sunday", cand ~rank:V.Class2 "ef-some-other-sunday",
-      [ po chair_of_st_peter_synth P.Ordinary; (paul_companion_synth, P.Ordinary, 999) ],
+      (* A third, unrelated candidate is OFFERED here deliberately, and is
+         correctly NOT admitted -- which is itself the point.
+
+         The fix-round re-review asked for a third commemoration so that
+         "spliced IMMEDIATELY after its own trigger" (RG110(c)'s own word)
+         could be told apart from "appended at the end of the list": with a
+         single-member result the two coincide, and it proved an
+         append-at-end variant passed the whole suite green.
+
+         Attempting it establishes something better than the test it asked
+         for: on this day-shape a third commemoration is RUBRICALLY
+         IMPOSSIBLE, so the distinction is unobservable BY CONSTRUCTION, not
+         merely unobserved. Shape (c) requires the trigger to LOSE the day
+         while still being admitted -- and a Class2 trigger can only lose to
+         a I-class day (RG 111(a): one privileged commemoration) or a
+         II-class Sunday (RG 111(b): one, and "scilicet de festo II
+         classis"). Both caps are ONE. Anything a third candidate could be
+         is either outranked by the trigger or excluded by the rank floor;
+         here [zzz-unrelated-commemoration] is Class3 and RG 111(b) drops
+         it, leaving the pair alone.
+         That is why the re-review's own domain sweep found shape (c) never
+         co-occurring with a third commemoration in 8 417 years: not an
+         accident of the data, a consequence of the rubric.
+
+         So RG110(c)'s "ante omnes alias commemorationes" half has no
+         reachable witness in the EF's real rubrical space, and the
+         adjacency this row asserts is exercised only against the pair
+         itself. The append-at-end variant therefore remains
+         indistinguishable from the splice on any input the engine can
+         actually construct -- recorded in the register rather than papered
+         over with a synthetic row that proves a shape no rubric permits. *)
+      [ po chair_of_st_peter_synth P.Ordinary;
+        (paul_companion_synth, P.Ordinary, 999);
+        po unrelated_comm_synth P.Ordinary ],
       [ "chair-of-st-peter"; "paul" ] );
     (* Defensive: a trigger slug is [observed], but its companion is simply
        not present among [comms] at all (a data gap, or -- as this exact