iteration 03 · 2026-07-14

DONE — PR #145 OPEN (stacked on #144) card 108substrate: signsEXACT parity 0.0/0.0 · first run

#108 sequitur_grammar_compression_ratio_logret_sign

Branch feat/odb-ext/sequitur_grammar_compression_ratio_logret_sign → terrylica/mql5 PR #145 (base = iter-02 branch; loop never merges). Arena-based faithful port of the probe linked-node Sequitur grammar; parity 5/5 · robustness 4/4 · rust:check 0 · check:all-gates 0 · pre-push ✓.

H5 results row (ledger detail)

Substrate	Tier/TOL	Parity batch / stream (max-abs-dev, SPLIT)	non-vacuity	pinned witness	C&H
signs (RG8 gap-nulled, never-reset ring)	EXACT (integer sum / L)	0.0 / 0.0 (11,200/11,200 bit-identical; FIRST full run)	compared == 11,200 == oracle-finite; 4/4 cells; H3 golden 12,000; H1 (MANDATORY) bit-identical ×11,200	EURUSD@5+0 → 0.5454545454545454 (RG8 gap window, bit-exact)	A 8/8 · D 10/10 · 0 conceded

H2: 108-EXCL-S fork cross-language exact — 60/60 breaches, max-abs = 1/L band (0.00504, 0.00506). H4 disjoint range [0.49, 0.6] bit-exact; sliding [0.47, 0.625] recorded. Oracle sha 47daa46f… (re-run byte-identical); golden sha e2310587…. Textbook pins: abab → (4,2); aaa overlap-skip → (3,1).

Decisions + findings (recorded LOUD)

(L+1)/L is NOT a universal Sequitur bound — a rule used exactly twice costs 3 and saves 2 (abab → 1.5); corrected pre-data. H4 uses the empirical 200-bar-window bound (0, 1.02], asserted in the parity loop; noted in the schema COMMENT.
Pointer-identity port: Python digram keys by id(rule) → stable Rust arena indices; digram map never iterated (H1 hazard closed by construction, then asserted on every window).
clippy collapsible_if ×3 → let-chain collapse; behavior-identical (parity re-verified, golden sha unchanged).
RG12: crypto odb-py #540 twin neither consulted nor executed; pysequitur MIT REFERENCE ONLY. The agnostic impl_b's historical 7-window crash lived in the harness's independent reimplementation — never in the pinned kernel.
Advisory: the BarBuilder impl file nears the local hook's 1000-line ceiling (repo gates unaffected); modularization follow-up suggested post-campaign.

In plain terms

Feeds the up/down bar-direction string into a deterministic grammar-building compressor (Sequitur) and reports how small the resulting grammar is relative to the original string. A low ratio means repetitive, hierarchical direction patterns; a ratio near 1 means random, incompressible alternation.

What landed (lockstep, one feature commit — 19 files)

kernel sequitur_grammar_compression_ratio_logret_sign.rs (arena grammar) + rolling state + mod.rs
BarOrthogonalExtV1 field · BarBuilder read-before-push wiring · writer.rs BarRow (last field)
schema.sql DDL AFTER etc_effort_to_compress_logret_sign · feature_metadata.yaml · regenerated docs/feature-catalog.html
oracle oracle_sequitur_grammar_compression_ratio_logret_sign.py + oracle/golden jsonl + .sha256 sidecars (dual-dir)
parity suite (5 gates incl. H1-every-window) + robustness suite (4 gates) + C&H record

Next: iter 04 (#98 sign_markov_inout_strength_asymmetry_flux) stacks on this branch.