{"abstract":"The product term uses addition instead of subtraction.","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. Quadratic discriminant. Exact operational definition: b*b-4*a*c","contract_signature":"a, b, c","evaluation_group":"model-f01571a82e518d37","failed_approach":"The discriminant coefficient loses a factor of two.","family":"xn-quadratic-discriminant","id":"FA-6131","implementations":{"attempt":{"sha256":"5f3f5086a1bf776c66b877789040d7da1271e5119385e8dc8897716edd2ed652","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(a, b, c):\n    return b*b-2*a*c\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1: (1, 0, -1)', solve(*(1, 0, -1)), 4)\ncheck('fixture 2: (1, 2, 1)', solve(*(1, 2, 1)), 0)\ncheck('fixture 3: (1, 0, 1)', solve(*(1, 0, 1)), -4)\ncheck('fixture 4: (2, 3, 1)', solve(*(2, 3, 1)), 1)\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":"fa0b46ec5a9ad30762a1432867142e8ffc87d27d23ae1b2747e76962976b20fd","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(a, b, c):\n    return b*b+4*a*c\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1: (1, 0, -1)', solve(*(1, 0, -1)), 4)\ncheck('fixture 2: (1, 2, 1)', solve(*(1, 2, 1)), 0)\ncheck('fixture 3: (1, 0, 1)', solve(*(1, 0, 1)), -4)\ncheck('fixture 4: (2, 3, 1)', solve(*(2, 3, 1)), 1)\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-quadratic-discriminant","generated_at":"2026-09-29T14:37:57.853066+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.","root_cause":"The product term uses addition instead of subtraction.","sha256":"6013142aa0e055f9888360035be0065ada35d76b7ec013037c73f5d45a811221","title":"Quadratic discriminant · 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":41.184,"exit_code":1,"observations":[{"actual":2,"check":"fixture 1: (1, 0, -1)","expected":4,"passed":false},{"actual":2,"check":"fixture 2: (1, 2, 1)","expected":0,"passed":false},{"actual":-2,"check":"fixture 3: (1, 0, 1)","expected":-4,"passed":false},{"actual":5,"check":"fixture 4: (2, 3, 1)","expected":1,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1: (1, 0, -1)\", \"actual\": 2, \"expected\": 4, \"passed\": false}, {\"check\": \"fixture 2: (1, 2, 1)\", \"actual\": 2, \"expected\": 0, \"passed\": false}, {\"check\": \"fixture 3: (1, 0, 1)\", \"actual\": -2, \"expected\": -4, \"passed\": false}, {\"check\": \"fixture 4: (2, 3, 1)\", \"actual\": 5, \"expected\": 1, \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":42.334,"exit_code":1,"observations":[{"actual":-4,"check":"fixture 1: (1, 0, -1)","expected":4,"passed":false},{"actual":8,"check":"fixture 2: (1, 2, 1)","expected":0,"passed":false},{"actual":4,"check":"fixture 3: (1, 0, 1)","expected":-4,"passed":false},{"actual":17,"check":"fixture 4: (2, 3, 1)","expected":1,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1: (1, 0, -1)\", \"actual\": -4, \"expected\": 4, \"passed\": false}, {\"check\": \"fixture 2: (1, 2, 1)\", \"actual\": 8, \"expected\": 0, \"passed\": false}, {\"check\": \"fixture 3: (1, 0, 1)\", \"actual\": 4, \"expected\": -4, \"passed\": false}, {\"check\": \"fixture 4: (2, 3, 1)\", \"actual\": 17, \"expected\": 1, \"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."}}