What we learned from the (reverted) step-2.2 attempt, stated as a
general principle in #000048 §5 "What we learned":
A recombination ("Mercury is the largest planet …" reusing the
source's "largest planet …" with its "Mercury") and a legitimate
cross-sentence summary ("Batman, who is the alias of Bruce Wayne,
lives in Gotham City." reusing two adjacent source sentences) are
the same SHAPE to any lexical signal — both scatter the answer's
content tokens across source clauses, and the recombination's
best-single-clause coverage (4/5 = 0.8) sits ABOVE the legit
summary's (4/6 = 0.67), so no token-coverage / clause-containment /
bigram threshold separates them in the safe direction. The
discriminating thing is *attribution* — in the source, are these
tokens attached to the same subject/predicate the answer attaches
them to? — which is a dependency / NLI question, not a string
metric. That's the boundary of the deterministic, no-LLM-judge
lexical verifier: absence signals (#000046 numeric gate, #000048
step 2.1 entity gate) and structure-of-the-model's-own-output
signals (step 2.4 segmenter) are lexical and work; "the source
contradicts this pairing" is not, and proxying it with a coverage
cut trades a small contrived-fixture win for honest demotions of
real summaries — a net loss against bench-maxing's 5-pp floor.
Updated: #000048 §2.2 (the attempted idea kept as design log + the
no-threshold-separates finding), §2.3 (now framed as the only path to
the last 2 — attribution / mini-NLI, its own ticket if ever), §3
(original plan annotated with the LANDED / ATTEMPTED+REVERTED / NOT
DONE outcome), §5 (the step-2.2 receipt + the "What we learned"
subsection + the closure recommendation). Stale cross-refs fixed:
TICKETS.md #000048 + #000046 rows, #000046 ticket Headroom section,
#000012 §8 #4 — all of which said "#000048 step 2.2 closes the last
2", now corrected to "step 2.2 attempted + reverted; the 2 recombination
fixtures stand as documented residue; #000048 §2.3 is the path if
ever wanted".
Recommendation unchanged: close#000048 at 2.1+2.4 (12 of 16 residual
items closed — formulate-hard 12/12, falsification-hard 10/12). Doc-
only — no code change.
russell@unturf.com
5428b3b1d6