{"abstract":"Filtering coefficients changes their exponents.","category":"Polynomial arithmetic","checks":4,"contract":"Integer coefficients in ascending power order and integer evaluation bounds; missing high-degree coefficients are zero. Rational outputs are reduced Fraction strings; the zero-polynomial degree is -1. Polynomial odd part. Exact operational definition: [c if i%2 else 0 for i,c in enumerate(coeff)]","evaluation_group":"model-a399e3507598b031","failed_approach":"Even powers are retained instead of odd powers.","family":"xn-polynomial-odd-part","id":"FA-6156","implementations":{"attempt":{"sha256":"8dad82a7d0b7d73abb26653209d3325a6123b01c12772c717416acf105ae9ded","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nimport calendar\nimport statistics\nimport itertools\nfrom fractions import Fraction\nfrom datetime import date, datetime, timedelta, timezone\nfrom decimal import Decimal, ROUND_HALF_UP, ROUND_DOWN, ROUND_CEILING, ROUND_FLOOR\n\nN = 1\nobservations = []\ndef solve(coeff):\n    return [c if i%2==0 else 0 for i,c in enumerate(coeff)]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1: ([1, 2, 3, 4],)', solve(*([1, 2, 3, 4],)), [0, 2, 0, 4])\ncheck('fixture 2: ([0, 1],)', solve(*([0, 1],)), [0, 1])\ncheck('fixture 3: ([5],)', solve(*([5],)), [0])\ncheck('fixture 4: ([],)', solve(*([],)), [])\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":"c73811d2ee2d70ac900378681e8adcb5e26670ab49f7c03db25ce149171853c8","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nimport calendar\nimport statistics\nimport itertools\nfrom fractions import Fraction\nfrom datetime import date, datetime, timedelta, timezone\nfrom decimal import Decimal, ROUND_HALF_UP, ROUND_DOWN, ROUND_CEILING, ROUND_FLOOR\n\nN = 1\nobservations = []\ndef solve(coeff):\n    return [c for i,c in enumerate(coeff) if i%2]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1: ([1, 2, 3, 4],)', solve(*([1, 2, 3, 4],)), [0, 2, 0, 4])\ncheck('fixture 2: ([0, 1],)', solve(*([0, 1],)), [0, 1])\ncheck('fixture 3: ([5],)', solve(*([5],)), [0])\ncheck('fixture 4: ([],)', solve(*([],)), [])\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"},"fixed":{"sha256":"dcb413fae7886c91e2417cc0d8a8bcc7d59e768ed8152c295d3c71aae33fe0fe","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nimport calendar\nimport statistics\nimport itertools\nfrom fractions import Fraction\nfrom datetime import date, datetime, timedelta, timezone\nfrom decimal import Decimal, ROUND_HALF_UP, ROUND_DOWN, ROUND_CEILING, ROUND_FLOOR\n\nN = 1\nobservations = []\ndef solve(coeff):\n    return [c if i%2 else 0 for i,c in enumerate(coeff)]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1: ([1, 2, 3, 4],)', solve(*([1, 2, 3, 4],)), [0, 2, 0, 4])\ncheck('fixture 2: ([0, 1],)', solve(*([0, 1],)), [0, 1])\ncheck('fixture 3: ([5],)', solve(*([5],)), [0])\ncheck('fixture 4: ([],)', solve(*([],)), [])\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":" 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":"xn-polynomial-odd-part","generated_at":"2026-09-29T14:37:58.209926+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Small exact fixtures expose this error without platform timing, external services, or probabilistic observations. Polynomial arithmetic results depend on the stated convention.","repair":"Apply the specified mathematical contract directly, preserving all terms and boundary cases: return [c if i%2 else 0 for i,c in enumerate(coeff)]","root_cause":"Filtering coefficients changes their exponents.","sha256":"50dbc09ec573422ecc76c736a382278080b4fbd6dc1499f36cb174a482e68bd4","title":"Polynomial odd part · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":44.552,"exit_code":1,"observations":[{"actual":[1,0,3,0],"check":"fixture 1: ([1, 2, 3, 4],)","expected":[0,2,0,4],"passed":false},{"actual":[0,0],"check":"fixture 2: ([0, 1],)","expected":[0,1],"passed":false},{"actual":[5],"check":"fixture 3: ([5],)","expected":[0],"passed":false},{"actual":[],"check":"fixture 4: ([],)","expected":[],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1: ([1, 2, 3, 4],)\", \"actual\": [1, 0, 3, 0], \"expected\": [0, 2, 0, 4], \"passed\": false}, {\"check\": \"fixture 2: ([0, 1],)\", \"actual\": [0, 0], \"expected\": [0, 1], \"passed\": false}, {\"check\": \"fixture 3: ([5],)\", \"actual\": [5], \"expected\": [0], \"passed\": false}, {\"check\": \"fixture 4: ([],)\", \"actual\": [], \"expected\": [], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":119.167,"exit_code":1,"observations":[{"actual":[2,4],"check":"fixture 1: ([1, 2, 3, 4],)","expected":[0,2,0,4],"passed":false},{"actual":[1],"check":"fixture 2: ([0, 1],)","expected":[0,1],"passed":false},{"actual":[],"check":"fixture 3: ([5],)","expected":[0],"passed":false},{"actual":[],"check":"fixture 4: ([],)","expected":[],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1: ([1, 2, 3, 4],)\", \"actual\": [2, 4], \"expected\": [0, 2, 0, 4], \"passed\": false}, {\"check\": \"fixture 2: ([0, 1],)\", \"actual\": [1], \"expected\": [0, 1], \"passed\": false}, {\"check\": \"fixture 3: ([5],)\", \"actual\": [], \"expected\": [0], \"passed\": false}, {\"check\": \"fixture 4: ([],)\", \"actual\": [], \"expected\": [], \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":43.59,"exit_code":0,"observations":[{"actual":[0,2,0,4],"check":"fixture 1: ([1, 2, 3, 4],)","expected":[0,2,0,4],"passed":true},{"actual":[0,1],"check":"fixture 2: ([0, 1],)","expected":[0,1],"passed":true},{"actual":[0],"check":"fixture 3: ([5],)","expected":[0],"passed":true},{"actual":[],"check":"fixture 4: ([],)","expected":[],"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1: ([1, 2, 3, 4],)\", \"actual\": [0, 2, 0, 4], \"expected\": [0, 2, 0, 4], \"passed\": true}, {\"check\": \"fixture 2: ([0, 1],)\", \"actual\": [0, 1], \"expected\": [0, 1], \"passed\": true}, {\"check\": \"fixture 3: ([5],)\", \"actual\": [0], \"expected\": [0], \"passed\": true}, {\"check\": \"fixture 4: ([],)\", \"actual\": [], \"expected\": [], \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}