{"abstract":"Aliquot blank is subtracted after dilution correction.","category":"Laboratory measurement reporting","checks":6,"contract":"Return signed (signal - aliquot_blank) * dilution as a Fraction string. Signals are rational strings and dilution is positive. Negative results remain reportable in this model.","contract_signature":"signal, blank, dilution","evaluation_group":"model-1ef2086d4c713e04","failed_approach":"Clamping negative aliquot differences to zero conceals signed blank-corrected results.","family":"z-laboratory_units-blank-basis","id":"FA-12396","implementations":{"attempt":{"sha256":"9d5fea203290069dcb48dbac8d13a6b1d6eb384e66469327e53a7062280641b0","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nfrom fractions import Fraction\nN = 1\nobservations = []\ndef solve(signal, blank, dilution):\n    return str(max(Fraction(0), Fraction(signal)-Fraction(blank))*dilution)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('blank scales with aliquot', solve(str(5*N), str(N), 3), str(12*N))\ncheck('negative blank correction retained', solve(str(N), str(2*N), 4), str(-4*N))\ncheck('blank equality', solve(str(N), str(N), 5), '0')\ncheck('undiluted sample', solve(str(3*N), str(N), 1), str(2*N))\ncheck('zero blank', solve(str(N), '0', 3), str(3*N))\ncheck('fractional blank', solve('1', '1/2', 3), '3/2')\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"broken":{"sha256":"1aadf6598537f2899bb76dffffcf9c21c05458dc3dec3d416905c37b0d2f9612","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nfrom fractions import Fraction\nN = 1\nobservations = []\ndef solve(signal, blank, dilution):\n    return str(Fraction(signal)*dilution-Fraction(blank))\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('blank scales with aliquot', solve(str(5*N), str(N), 3), str(12*N))\ncheck('negative blank correction retained', solve(str(N), str(2*N), 4), str(-4*N))\ncheck('blank equality', solve(str(N), str(N), 5), '0')\ncheck('undiluted sample', solve(str(3*N), str(N), 1), str(2*N))\ncheck('zero blank', solve(str(N), '0', 3), str(3*N))\ncheck('fractional blank', solve('1', '1/2', 3), '3/2')\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"}},"limitations":"Synthetic integer/rational fixtures only; no instrument validation or clinical interpretation. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.","method":"Deterministic executable model with adversarial boundary fixtures.","provenance":{"created_by":"Failure Map","dependencies":"Python standard library","family":"z-laboratory_units-blank-basis","generated_at":"2026-09-29T14:38:56.568518+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A deterministic synthetic laboratory reporting model isolates a software metadata contract; it is not a clinical procedure.","root_cause":"Blank and sample values expressed on the aliquot basis are combined on different bases.","sha256":"b24f4de8000ca784d88efee1b406c3cc71fe6f5e1cc65288a0485b441d4ee53e","title":"Aliquot blank is subtracted after dilution correction · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":44.291,"exit_code":1,"observations":[{"actual":"12","check":"blank scales with aliquot","expected":"12","passed":true},{"actual":"0","check":"negative blank correction retained","expected":"-4","passed":false},{"actual":"0","check":"blank equality","expected":"0","passed":true},{"actual":"2","check":"undiluted sample","expected":"2","passed":true},{"actual":"3","check":"zero blank","expected":"3","passed":true},{"actual":"3/2","check":"fractional blank","expected":"3/2","passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"blank scales with aliquot\", \"actual\": \"12\", \"expected\": \"12\", \"passed\": true}, {\"check\": \"negative blank correction retained\", \"actual\": \"0\", \"expected\": \"-4\", \"passed\": false}, {\"check\": \"blank equality\", \"actual\": \"0\", \"expected\": \"0\", \"passed\": true}, {\"check\": \"undiluted sample\", \"actual\": \"2\", \"expected\": \"2\", \"passed\": true}, {\"check\": \"zero blank\", \"actual\": \"3\", \"expected\": \"3\", \"passed\": true}, {\"check\": \"fractional blank\", \"actual\": \"3/2\", \"expected\": \"3/2\", \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":43.328,"exit_code":1,"observations":[{"actual":"14","check":"blank scales with aliquot","expected":"12","passed":false},{"actual":"2","check":"negative blank correction retained","expected":"-4","passed":false},{"actual":"4","check":"blank equality","expected":"0","passed":false},{"actual":"2","check":"undiluted sample","expected":"2","passed":true},{"actual":"3","check":"zero blank","expected":"3","passed":true},{"actual":"5/2","check":"fractional blank","expected":"3/2","passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"blank scales with aliquot\", \"actual\": \"14\", \"expected\": \"12\", \"passed\": false}, {\"check\": \"negative blank correction retained\", \"actual\": \"2\", \"expected\": \"-4\", \"passed\": false}, {\"check\": \"blank equality\", \"actual\": \"4\", \"expected\": \"0\", \"passed\": false}, {\"check\": \"undiluted sample\", \"actual\": \"2\", \"expected\": \"2\", \"passed\": true}, {\"check\": \"zero blank\", \"actual\": \"3\", \"expected\": \"3\", \"passed\": true}, {\"check\": \"fractional blank\", \"actual\": \"5/2\", \"expected\": \"3/2\", \"passed\": false}], \"passed\": false}\n"}},"member_only":{"stages":["fixed"],"fields":["implementations.fixed","verification.fixed","harness","repair"],"note":"The verified repair, its recorded checks, the repair description, and the scoring harness are available to members."}}