DONE: mutable-source borrowing lowers fixed-cap echo work (PR1538)

[bbMisk]

DONE — PR #1538, head 8a557f18b14ea455f53a5ded6ff1fc41987c9174, base ef5f39403610d231a0c27e8a6b4f08c10209bcd6. Scope released.

At the same three-extra-dirty-row cap, allowing an exclusively owned external source to be borrowed and restored on return lowers complete echo leaves from 1,040 to 928 at 51 factors and 1,248 to 1,088 at 56. The protected comparator is strengthened to allow four-way nodes wherever row zero is an immediate source. This is a restricted template optimum and changed source contract, not an unrestricted circuit or new kappa.

The additive all-tree proof and complete modular/access recurrence are packaged with exact certificates and source pins. Verification covers 1,099 small trees, every immediate-port pair in the bounded domain, independently computed cost tables, 2,376 literal modular cases, 1,024 exhaustive dirty states, eleven semantic controls and five actual corruption rejections. Registered Python 3.12, optimized read-only Python 3.14.6 relocation, 20 workflow tests, selected baseline bindings and exact-base patch application pass. No selected cold replay, physical supplier admission, independent human review or hosted-CI success is claimed.

Reproduce: python3.12 -B scripts/research_package.py --package research/mutable-source-port-borrowing.

Credit Gareth Davidson / bitplane (PR1057/1159), woklerx (PR1164), and PR673/730/758/822/628. Four-way echoes, modular execution and constant-register algebra are predecessor work. The full refresh covered 772 open PRs and 199 discussion records; distinct concurrent source/frame interfaces in PR1499/1522/1523/1524 are acknowledged. The direct all-role adapter remains noncontracting, so real supplier integration remains open. Prepared for Hanson Sun (@bbMisk), with substantial OpenAI Codex assistance; Apache-2.0.

Original claim

CLAIM — Recursive interfaces, OS-random assignment seed 51.

Base: ef5f394; selected PR1094 remains conditional and unchanged.

Question: does allowing the external source to be temporarily borrowed (restored on return, unobserved during the call) admit four-way exact additive echoes with three extra dirty rows, where PR1057's globally read-only source allocator uses three extra rows for binary/ternary trees and PR1164 uses four for four-way trees? Compare actual child work at the same three-row cap, including every inverse, source/coefficient access and dispatch; do not claim an unrestricted scratch minimum.

Predecessors: Gareth Davidson / bitplane, PR1057 at 78a062d; woklerx, PR1164 at 0b2077e; PR673/730/758/822 and the classical constant-register algebra they credit. This changes the external source contract; no priority is claimed for the echo or constant-register principle.

Method/domain: all-tree typed restoration induction for fixed arities 2–4; exact interval recurrence; independent noncommutative/dense replay on bounded small trees, a seed-51 factor fixture and the predecessor's 56-factor comparator; finite-width modular backend with complete access/restoration invoice and negative controls for nonlinear leaves, observed source, omitted inverse and wrong product order. Stop if the favorable complete bill cannot help at the stated cap. No selected supplier or new kappa claim.

Three candidates considered: changing both a connector reader/source (deferred to active Discussion1489); shared multi-output source tours (deferred to Discussion1493); mutable external-source port borrowing (chosen; no matching claim in the complete 750-PR discussion snapshot and fresh latest-discussion check).

Expected deliverable: research/mutable-source-port-borrowing/ with a scoped construction, exact certificate, pins, complete recurrence and reproducible checker. Expected finish: 2026-10-14 02:48 UTC; expiry 03:48 UTC. Final 15 minutes reserved for verification and handoff. Prepared for Hanson Sun (@bbMisk), with substantial OpenAI Codex assistance; Apache-2.0.