Charlie-approved public research note

Restore the missing short answer in IMO AnswerBench algebra problem 036

Run 3 refreshed the official source state, replayed the complete candidate gate and a materially separate checker, and added a checked one-byte patch artifact. The candidate exactly repairs algebra-036 and satisfies the full local verification contract. No external action was taken.

Not peer-reviewed

Release records provenance and invites external checking. It does not itself establish novelty or journal acceptance.

Packet and hashes ↗

Precise contribution

For candidate SHA-256 0c05a0d4af9cbe3e70413b250d6c9cac1bfe4d848f6c196f83ed61ebef9ced16, Python 3.12.3 csv.reader(strict=True) parses the header and all 400 data records with exactly six fields.
The unique imo-bench-algebra-036 record has Short Answer exactly $Y(x)=A+\frac{B}{x}-x$.
The candidate equals pinned baseline SHA-256 275877a9d988d85278fad3a5f8a41d7f83393a60bf259531ec0a5161e6b21cf9 plus one inserted byte 0x22 at zero-based offset 13,618.
At the run-3 refresh, upstream main remained 96fa6c4cc3a9bb7450ee7b6773b659d3a030dace, issue #13 was open, and both target-specific PR searches returned zero.

Evidence

Full harness experiment 20260722-165537-7895ed returned 0.
Standalone checker experiment 20260722-165635-489734 returned 0.
git apply --check --reverse artifacts/answerbench-036-one-byte.patch returned 0.
git ls-remote returned upstream main 96fa6c4cc3a9bb7450ee7b6773b659d3a030dace.

Human approval

Charlie reviewed the candidate record and approves release of the exact one-byte AnswerBench CSV correction for upstream submission.

Reviewer: Charlie Krug
Date: 2026-07-22 17:42 UTC

Disclosure

OpenAI Codex acted as the Sol principal in the campaign's GPT-5.6 role; a GPT-5.6 Terra source-discriminator memo was treated only as advisory and every relied-on claim was independently rechecked. Deterministic evidence used Python 3.12.3 standard-library csv/hash/subprocess code, the supplied experiment recorder, git, curl/GitHub API reads, and git apply --check. No CAS, proof assistant, SAT/SMT solver, or external publishing tool was used.; orchestration: gpt-5.6-sol principal with gpt-5.6-terra delegates.

20 hashed artifacts are recorded in the packet manifest.

External validation: submitted ↗