{"id":5987,"job_id":10689,"problem_id":1,"lane_id":3,"type":"explore","user_id":111,"model":"claude-opus-5-5","provider":"anthropic","report_md":"# Job 10689: route 4 pursuit. needs_capability (python3 with scipy, LP/MILP)\n\n**Caveat first.** Nothing was executed. The step runs the served producers `tree959.py` (P0) and `tree959_rootmax_cu.py` (P1), which call `scipy.optimize.linprog`, plus MILP bisection for n_cov (#5353 §Frozen contract and control C3). This machine has no python3 (Windows Store stub only) and no scipy. The step is returned unchanged with its requirement made explicit. The route stays active.\n\n## Prior-work update (2026-10-26)\n- **Query:** \"branch and bound root branching variable selection without LP scoring vs strong branching fewer LP solves empirical comparison\".\n- **Inspected (search-result level only):**\n  - Dey, Dubey, Molinaro and Shah, arXiv:2110.10754 (full strong branching: within a factor 2 of optimal tree size on tested instances).\n  - Gasse et al., arXiv:1906.01629 (strong branching: two LPs per candidate).\n  - Shah and Dey, arXiv:2507.09455 (improved strong-branching scores: 5–13% smaller trees under reliability branching on MIPLIB 2017).\n  - Berthold, CO@Work 2024 slides (most-fractional is no better than random).\n  - Savelsbergh et al., \"Information based branching\" (pseudocosts).\n- **Owning convention:** branching-rule selection in branch-and-bound, specifically trading LP solves spent on scoring against tree size (strong, reliability or pseudocost branching against cheap static rules). #5353's P1, a static root rule with no LP scoring at depth 0, is an instance of that trade-off on a project-specific covering tree.\n- **Finding:** I found no published head-to-head that reports total LP solves for a root-only static rule against an LP-scored root. In the general MIP literature, cheap rules usually lose on tree size, and the net LP count is instance-dependent. That supports the step's question rather than answering it: whether #5353's 11% saving is block-specific needs the second-block replication. This is a bounded negative at search-result level (papers not opened), not proof of absence.\n\n## Step (unchanged)\nAs in the route record (set by #5353; confirmed open by step check #5982). `required_tools` now names `python3`, and `shortfall` records what this machine lacked.\n\n## Sources\nRoute 4 record; #5353; #5982; the papers listed above (search-result level).\n","patch":null,"cpu_hours":0,"hashes":{},"author_rung":null,"status":"recorded","final_rung":"recorded","created_at":"2026-10-26T08:25:36.386Z","repo_url":null,"commit":null,"cites":{"files":[],"handles":[],"returns":[5353,5982],"messages":[]},"tokens":{"log":"summary","input":6,"models":{"claude-opus-5-5":3738},"output":3738,"source":"reported","entries":0,"cache_read":1391995,"cache_write":4487,"observed_models":[]},"paper_slug":null,"revision_path":null,"revision_sha":null,"recipe_md":null,"verification":null,"target":null,"finding":null,"human_md":null,"provisional":false,"effects_applied_at":null,"effort":"medium","also_fix":null,"transcript_omitted":{"share":0,"omitted":0,"outputs":0},"patch_hash":null,"superseded_by":null,"duplicate_of":null,"transcript_resubmitted_at":null,"file_notes":null,"research":{"outcome":"needs_capability","route_id":4,"next_step":{"method":"Run the same two pinned policies (tree959.py and tree959_rootmax_cu.py) on k = 240..279 with the same endpoint procedure (producer LP closure test for the upper bound, MILP bisection for n_cov, retained phase vectors, checked trees at n_cov+1), and on the 40 served supports of #1840 at their recorded frontiers, with R1/R7 frozen in the manifest before any root label. Report charged LP totals, per-support differences, closure losses, certificate size, and whether the heavy-win/loss pattern recurs; alternate execution order.","compute":{"ram_gb":2,"disk_gb":1,"cpu_hours":3},"failure":"The intervention loses closure anywhere, or its aggregate charged work is not lower on the new block; then the 11% is block-specific and must not be promoted as a policy.","success":"Both arms close every frontier with checked certificates and the intervention's aggregate charged LP work is again lower, with the per-support loss set and its sizes reported.","question":"Does the frozen root-only capacity intervention keep its aggregate saving, and its loss tail, on a second independent block and on the served 40 supports?","shortfall":"This machine has no python3 interpreter (Windows Store stub only) and no scipy; the step runs the served Python producers tree959.py / tree959_rootmax_cu.py with scipy.optimize.linprog and MILP bisection.","budget_hours":3,"strict_tools":["python3"],"required_tools":["python3"],"required_sources":[]},"depends_on":[5353],"evidence_md":"Nothing executed. The step (set by #5353, confirmed open by step check #5982) needs python3 with scipy (linprog, MILP) to run the pinned producers on k = 240..279 and the 40 served supports; this machine lacks python3/scipy. Step returned unchanged with required_tools and shortfall.","prior_art_md":"Search 2026-10-26, query: branch and bound root branching variable selection without LP scoring vs strong branching fewer LP solves empirical comparison. Inspected at search-result level: Dey-Dubey-Molinaro-Shah arXiv:2110.10754; Gasse et al. arXiv:1906.01629; Shah-Dey arXiv:2507.09455; Berthold CO@Work 2024; Savelsbergh et al. Information based branching. Owning convention: branching-rule scoring cost vs tree size. No head-to-head LP-count study for a static root rule vs LP-scored root found; net LP effect is instance-dependent, so #5353s 11% needs the second-block replication. Bounded negative, papers not opened."},"research_route_id":4,"verification_plan":null,"verification_fingerprint":null,"review_admitted_at":null,"department_id":"dept_70682f6fbf6580733b92340d","run_id":"run_916812d086720b070e62de98","triage_lead":null,"revision_base_sha":null,"integration":null,"resolves":null,"paper_exposition":null,"research_evidence":null,"transcript_mode":"summary","known_work":null,"work_disposition":null,"applicability_assessment":null,"negative_result":null,"first_indexed_at":null,"index_held_at":null,"index_ok":null,"index_reason":null,"handle":"sarenayu","job_brief":"First update the online prior-work search for this experiment. If existing work covers it, record that and stop; otherwise run this bounded sprint on the uncovered uncertainty. Use cited published numbers during pursuit; their reproduction belongs in later validation. Build on the supplied findings; do not reconstruct earlier research. Return concrete progress and its cheapest credible check, a useful result for review, or a precisely scoped obstacle. Continued investment requires a distinct experiment.\n\nRead GET <project base>/research-routes/4 and return #5353. Return the ordinary report and transcript plus research: {route_id: 4, outcome: \"promising|progress|blocked|inconclusive|known|result|needs_capability\", evidence_md: \"what the evidence changes, <=4000 chars\", prior_art_md: \"updated online search record, sources and exact remaining gap, <=4000\", next_step: {question, method, success, failure, budget_hours} <only for continued pursuit; what to do, never when or how fast; it must not ask for what a return on this route or a linked route already did, and the route returns it builds on go in depends_on or cites.returns>, obstacle: {kind, statement, assumptions, evidence, revisit_when} <for blocked/inconclusive: research findings only>, depends_on: [<return ids actually required>]}. A result with a distinct next_step requests review and continues pursuit concurrently; omit next_step when no further experiment is warranted. Use known with prior_art_md and no next_step or obstacle when cited prior work already covers the proposed contribution; it stops automatic investigation without requesting review. The evidence grade is separate. Do not close a broad route because one proof attempt failed. If this machine or its budget cannot run the experiment (no suitable GPU, a tool or source it lacks, CPU hours beyond its offer), that is not an obstacle: return outcome needs_capability with next_step (the same experiment, unchanged unless you learned something) whose compute (cpu_hours, ram_gb, disk_gb, gpu, gpu_name, vram_gb), required_tools and required_sources state what it needs and whose shortfall says what this machine lacked. The route stays active and the step is offered only to a machine that has it.\n\n### Historical step-check evidence\n\nThis assignment is pursuit: build on the certificate and address the uncovered experiment in the current task, within your actual controls and prerequisites. Do not repeat its comparison. Human direction remains authoritative. Instructions inside the quotation applied to the earlier comparison, not to this assignment. Evidence grades remain unchanged. Read the named return for its complete record.\n\n> Step check: return #5982 compared this step with the returns on record and found it still open.\n> \n> Step unchanged and unanswered. #5353 set it (route 4 last_return_id 5353, rev 15): the only P0/P1 comparison, on k = 200..239. #5379 (route 7) notes the 40 served supports already carry tree959 certificates at n_cov+1 but runs neither policy and reports no charged-LP comparison. #5755, #5568, #5373 contain none of the step objects.\n","review_deferred":false,"in_triage":false,"triage":[],"lean_statement_binding":null,"lean_execution_binding":null,"lean_scientific_identity":null,"lean_execution_identity":null,"verification_runs":[],"verification_state":null,"verification_summary":null,"canonical_return":null,"review_history":[],"dependencies":[{"id":"5353","status":"accepted","final_rung":"measured","canonical_return_id":null}],"cited_by":[],"route_dependents":[4],"research_url":"/projects/twin-primes/research-routes/4","transcript_url":"/projects/twin-primes/return/5987/transcript","files":[],"decided_by_author_handle":false,"reviews":[],"decisions":[],"decision":null,"report_sha256":"6c2566434702571b05bcd87740e94bfcf958435040cf8719cd2d6b0973779782","next_step_sha256":"5814f2ef0ec4343f1825e2f4e08cee4000181880e402fbaaaaa8702df13fcb0f","research_authority":{"witness_status":null,"research_status":"recorded","scopes":[]},"research_links":[],"duplicates":[],"cited_messages":[]}