Completes the all/no/some square. `some` is read for the first time:
"All mammals are vertebrates. Some whales are mammals. Therefore some
whales are vertebrates." is decided entailed; "All unicorns are horned.
Therefore some unicorns are horned." is decided unsettled, with the
no-existential-import reading disclosed in the surface.
Mechanism (generate/proof_chain/exist.py): v5-VP's per-individual
lowering over a domain widened by one Skolem witness per existential
premise and — the load-bearing part — one ARBITRARY element per
existential conclusion, at which every universal still instantiates and
about which no premise asserts anything. Refuting an existential means
deriving a universal, and the arbitrary element is what makes that
derivation genuine instead of an assumption of domain closure: without
it "Rex is a wolf. Rex is not tame. Therefore some wolves are tame."
reads as REFUTED from a domain of one wolf. With it, UNKNOWN.
Four `en_exist_*` bands earned SERVE at 720x wrong=0 on the first arena
seal (25-band ledger); the 32-case hand-authored v2_exist split passed
32/32 first run; full lane 166/166 wrong=0 across six splits.
Also fixes a wrong-answer path this work uncovered in Band v1b
(ADR-0261 §5.1): `to_syllogism` FILTERED premises it could not express
out of the projection and answered from the remainder, so "Aristotle is
a philosopher. All philosophers are scholars. Therefore some scholars
are philosophers." lost its only witness and was served "that doesn't
follow". It now refuses — matching its propositional sibling
`to_deductive_logic`, which always has — and the argument falls through
to the bands that can hold a singular fact. The categorical band
re-earned SERVE 720/720 after the change; both examples are pinned as
regression cases.
Promotion: `ds-mem-0020` declined -> unknown (ADR-0258's existential
scope-out, now read; an anonymous witness never transfers to a named
individual, so UNKNOWN is its honest verdict, not entailed).
[Verification]: core test --suite deductive 232 passed; reader tests
33/33; register+surface tests 52 passed; arena 25 bands x 720 wrong=0
(all SERVE); lane 166/166 wrong=0; lane SHAs 9/10 match (public_demo
drift is pre-existing on the base commit and unrelated — evidence in
the Tier-S brief).
Generalization arc Phase 1.1 (Tier F, docs/plans/generalization-arc-2026-07-24.md):
"All philosophers teach. Socrates is a philosopher. Therefore Socrates
teaches." now reads and decides — the ADR-0258 §6.3 verb-predicate
scope-out, and the reading gate for Phase 2's subject serving.
generate/proof_chain/verb.py extends v3-MEM's per-individual lowering with
a second atom family in one shared space: membership atoms (v3-MEM's own
parsers reused verbatim) + verb atoms (individual, verb-lemma-group,
object-term). Verb universals instantiate as mem(i,C) -> [~]verb(i), so a
copula-minted membership fact discharges a verb rule. The ONE new semantic
identification is closed 3sg agreement (verb-specific irregular table +
the three regular suffix rules — deliberately NOT the noun table, which
would misroute "lives"/"leaves"). Scope-tight segmentation: single-token
name/class/verb/object shapes only; everything longer refuses typed
(tense_out_of_band joins the closed reason vocabulary). Rendered by
render_entailment_verb (member surface, UNKNOWN scoping extended to the
verb reading). Rides deduction_serving_enabled (default off); pure
widening — every previously-served argument byte-identical, no existing
lane case changed outcome.
Earned: 4 en_verb_* bands x 720 arena wrong=0 (first seal), ledger resealed
at 21 bands; corpus soundness asserted against the independent truth-table
oracle over each template's intended lowering (15,120 cases, INV-25).
Lane: v2_verb 28 hand-authored real cases 28/28 first run; full lane
134/134 wrong=0 across five splits. Surgical single-line pin update +
CLAIMS regen.
Stacked on feat/generalization-phase0 (merge that first — shared
verify_lane_shas.py / CLAIMS.md / generate_claims.py lane-ADR mapping).
[Verification]: verb reader tests 34/34; deduction battery 86/86
(surface +5, e2e +1, lane +1) in-worktree; arena seal + oracle
cross-check green; smoke + warmed_session via pre-push gate.
Composes v2-EN's connective grammar (if/then, or, and, either) with
v3-MEM's singular-membership sentence reading over one shared
per-individual atom space, so "If Socrates is a man then Socrates is
mortal. Socrates is a man. Therefore Socrates is mortal." decides — the
exact gap ADR-0258 §6.1 reserved. Genuinely fuses the two mechanisms: a
bare universal's instantiated atom can unify (via the same closed
morphology relation) with a connective leaf's atom, deciding arguments
neither band alone could.
- generate/proof_chain/cond_member.py: new reader. A sentence is checked
for a connective token BEFORE the universal-lead check (so a stray
connective can never leak into an opaque name/class run); reuses v3-MEM's
own _parse_singular/_parse_universal verbatim (already negation-aware,
so no separate negation layer is needed, unlike v2-EN's opaque minter).
Four new shape-bands (fused/disjunctive/chain/conditional), each earning
its own SERVE license.
- chat/deduction_surface.py: new fallback tier tried strictly after v3-MEM
— pure widening, every previously-served argument stays byte-identical.
- evals/deduction_serve/practice/gold.py: 4 new synthetic template groups
(20 templates), reusing the v3-MEM case generator; intended formulas
cross-checked against the independent oracle (INV-25).
- evals/deduction_serve/v2_condmem/: 26 hand-authored real-English cases,
content-disjoint from the synthetic corpus.
- ds-mem-0024 promoted declined -> unknown (not entailed — the antecedent
is never asserted in that text; this is the first promotion in the
corpus that doesn't land on entailed).
- Ledger re-sealed to 17 bands; deduction_serve_v1 lane SHA re-pinned
(surgical single-line edit, not a blanket --update).
Verification: core test --suite deductive 160 passed (31 new reader
tests); practice arena 17 bands x 720 wrong=0, all SERVE-licensed; lane
splits v1 28/28, v2_en 26/26, v2_member 26/26, v2_condmem 26/26; smoke 180
passed; warmed_session 10 passed. Flag deduction_serving_enabled stays
default-off.
New evals/deduction_serve/ lane scores the PRODUCTION serving decider
(the exact comprehend -> to_deductive_logic -> evaluate_entailment_with_trace
pipeline chat/deduction_surface.py runs) end-to-end from raw text --
distinct from evals/deductive_logic (bare engine vs formula strings) and
evals/comprehension/propositional_runner.py (reader fidelity vs the
independent oracle, not the production engine). This is the only lane
proving the capability core chat actually serves.
27 hand-authored cases (gold computed by independent logical reasoning,
not copied from a first engine run), 4 classes: entailed/refuted/unknown/
declined. 27/27 correct, wrong=0. Wired into core test --suite deductive
(tests/test_deduction_serve_lane.py) and SHA-pinned in
scripts/verify_lane_shas.py (deduction_serve_v1).
Honesty check during authoring: a case intended as 'entailed'
(contraposition, 'Therefore if not q then not p') actually declined --
tracing why found a genuine reader-grammar boundary (negation cannot
nest inside an if/then clause; generate/meaning_graph/reader.py's _chunk
rejects it). Reclassified to declined/out_of_band_nested_negation
(documented in contract.md) rather than forcing an artificial pass, and
added a replacement entailed case (three-hop chain) to keep coverage.
Out-of-scope finding (documented, not fixed here): running
scripts/verify_lane_shas.py --update to compute this lane's pin also
re-executed every OTHER registered lane and surfaced two pre-existing,
unrelated problems on main -- miner_loop_closure/curriculum_loop_closure/
demo_composition regenerate non-deterministic content IDs (their
committed pins don't reproduce even on a clean checkout), and public_demo
errors outright (matches the known env-timeout flake in project memory).
Reverted all four lanes' results/*.json and PINNED_SHAS entries to their
original committed values -- this PR's only PINNED_SHAS change is the new
deduction_serve_v1 entry.
[Verification]: smoke 180 passed; cognition 122 passed/1 skipped;
core test --suite deductive 25 passed; evals.deduction_serve.runner
27/27 wrong=0; pinned SHA independently re-verified against the
committed report.json bytes.
