{"abstract":"The reduction disagrees with its explicit aggregation oracle.","category":"Numerical aggregation","checks":9,"contract":"Bins [left,right,mass] have positive widths and nonnegative integer masses. Treat each bin as uniform density. Return exact mass in query [a,b] as a Fraction string; reversed/empty queries have zero mass.","evaluation_group":"s3-na-histogram-interval-mass","failed_approach":"Selecting the largest contribution also loses mass from other bins.","family":"s3-numerical-aggregation-histogram-interval-mass-average-bins","id":"FA-13046","implementations":{"attempt":{"sha256":"62069cd7df7dd5f435dfed2ef958b2777e1234cd962cd5fd71f9678294e6f5e1","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nfrom fractions import Fraction\nfrom collections import Counter, defaultdict\nimport math\nimport itertools\nN = 1\nobservations = []\ndef solve(bins, a, b):\n    return str(max([Fraction(0)]+[Fraction(m*max(0,min(r,b)-max(l,a)),r-l) for l,r,m in bins])) if a<b else \"0\"\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('regression 1', solve(*([[0, 4, 8], [4, 10, 3]], 2, 7)), '11/2')\ncheck('regression 2', solve(*([[0, 4, 8]], 1, 2)), '2')\ncheck('regression 3', solve(*([[0, 4, 8]], -3, 8)), '8')\ncheck('regression 4', solve(*([[0, 4, 8]], 4, 9)), '0')\ncheck('regression 5', solve(*([[0, 4, 8]], 7, 9)), '0')\ncheck('regression 6', solve(*([], 0, 1)), '0')\ncheck('regression 7', solve(*([[0, 4, 8]], 3, 1)), '0')\ncheck('regression 8', solve(*([[2, 7, 10], [10, 12, 8]], 0, 11)), '14')\ncheck(\"variable density mass\",solve([[0,N+2,2*(N+2)]],1,N+1),str(2*N))\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":"4d9b650ef41220fcccb01c77fc1d8702f8bd3f88da82b24a13e3a424fbde1dc4","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nfrom fractions import Fraction\nfrom collections import Counter, defaultdict\nimport math\nimport itertools\nN = 1\nobservations = []\ndef solve(bins, a, b):\n    return str(sum((Fraction(m*max(0,min(r,b)-max(l,a)),r-l) for l,r,m in bins),Fraction(0))/max(1,len(bins))) if a<b else \"0\"\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('regression 1', solve(*([[0, 4, 8], [4, 10, 3]], 2, 7)), '11/2')\ncheck('regression 2', solve(*([[0, 4, 8]], 1, 2)), '2')\ncheck('regression 3', solve(*([[0, 4, 8]], -3, 8)), '8')\ncheck('regression 4', solve(*([[0, 4, 8]], 4, 9)), '0')\ncheck('regression 5', solve(*([[0, 4, 8]], 7, 9)), '0')\ncheck('regression 6', solve(*([], 0, 1)), '0')\ncheck('regression 7', solve(*([[0, 4, 8]], 3, 1)), '0')\ncheck('regression 8', solve(*([[2, 7, 10], [10, 12, 8]], 0, 11)), '14')\ncheck(\"variable density mass\",solve([[0,N+2,2*(N+2)]],1,N+1),str(2*N))\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":"107370a03c9fab1f517251c09773874ca40a3249c1e245496d2d4461c1e39f40","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nfrom fractions import Fraction\nfrom collections import Counter, defaultdict\nimport math\nimport itertools\nN = 1\nobservations = []\ndef solve(bins, a, b):\n    return str(sum((Fraction(m*max(0,min(r,b)-max(l,a)),r-l) for l,r,m in bins),Fraction(0))) if a<b else \"0\"\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('regression 1', solve(*([[0, 4, 8], [4, 10, 3]], 2, 7)), '11/2')\ncheck('regression 2', solve(*([[0, 4, 8]], 1, 2)), '2')\ncheck('regression 3', solve(*([[0, 4, 8]], -3, 8)), '8')\ncheck('regression 4', solve(*([[0, 4, 8]], 4, 9)), '0')\ncheck('regression 5', solve(*([[0, 4, 8]], 7, 9)), '0')\ncheck('regression 6', solve(*([], 0, 1)), '0')\ncheck('regression 7', solve(*([[0, 4, 8]], 3, 1)), '0')\ncheck('regression 8', solve(*([[2, 7, 10], [10, 12, 8]], 0, 11)), '14')\ncheck(\"variable density mass\",solve([[0,N+2,2*(N+2)]],1,N+1),str(2*N))\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":"Small offline integer/rational inputs only; no performance, statistical inference, or production-library conformance claim. 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":"s3-numerical-aggregation-histogram-interval-mass-average-bins","generated_at":"2026-09-29T14:39:02.976912+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Exact bounded examples isolate a reduction defect without floating-point or external-service effects.","repair":"Preserve the histogram interval mass contract at the identified reduction decision.","root_cause":"Bin contributions are averaged rather than accumulated.","sha256":"e809e10a088b7ae2f9a9f109749e3d8461783364acea412d4cb43e21fb435724","title":"Histogram interval mass: Bin contributions are averaged rather than accumulated. · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":43.449,"exit_code":1,"observations":[{"actual":"4","check":"regression 1","expected":"11/2","passed":false},{"actual":"2","check":"regression 2","expected":"2","passed":true},{"actual":"8","check":"regression 3","expected":"8","passed":true},{"actual":"0","check":"regression 4","expected":"0","passed":true},{"actual":"0","check":"regression 5","expected":"0","passed":true},{"actual":"0","check":"regression 6","expected":"0","passed":true},{"actual":"0","check":"regression 7","expected":"0","passed":true},{"actual":"10","check":"regression 8","expected":"14","passed":false},{"actual":"2","check":"variable density mass","expected":"2","passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression 1\", \"actual\": \"4\", \"expected\": \"11/2\", \"passed\": false}, {\"check\": \"regression 2\", \"actual\": \"2\", \"expected\": \"2\", \"passed\": true}, {\"check\": \"regression 3\", \"actual\": \"8\", \"expected\": \"8\", \"passed\": true}, {\"check\": \"regression 4\", \"actual\": \"0\", \"expected\": \"0\", \"passed\": true}, {\"check\": \"regression 5\", \"actual\": \"0\", \"expected\": \"0\", \"passed\": true}, {\"check\": \"regression 6\", \"actual\": \"0\", \"expected\": \"0\", \"passed\": true}, {\"check\": \"regression 7\", \"actual\": \"0\", \"expected\": \"0\", \"passed\": true}, {\"check\": \"regression 8\", \"actual\": \"10\", \"expected\": \"14\", \"passed\": false}, {\"check\": \"variable density mass\", \"actual\": \"2\", \"expected\": \"2\", \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":44.306,"exit_code":1,"observations":[{"actual":"11/4","check":"regression 1","expected":"11/2","passed":false},{"actual":"2","check":"regression 2","expected":"2","passed":true},{"actual":"8","check":"regression 3","expected":"8","passed":true},{"actual":"0","check":"regression 4","expected":"0","passed":true},{"actual":"0","check":"regression 5","expected":"0","passed":true},{"actual":"0","check":"regression 6","expected":"0","passed":true},{"actual":"0","check":"regression 7","expected":"0","passed":true},{"actual":"7","check":"regression 8","expected":"14","passed":false},{"actual":"2","check":"variable density mass","expected":"2","passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression 1\", \"actual\": \"11/4\", \"expected\": \"11/2\", \"passed\": false}, {\"check\": \"regression 2\", \"actual\": \"2\", \"expected\": \"2\", \"passed\": true}, {\"check\": \"regression 3\", \"actual\": \"8\", \"expected\": \"8\", \"passed\": true}, {\"check\": \"regression 4\", \"actual\": \"0\", \"expected\": \"0\", \"passed\": true}, {\"check\": \"regression 5\", \"actual\": \"0\", \"expected\": \"0\", \"passed\": true}, {\"check\": \"regression 6\", \"actual\": \"0\", \"expected\": \"0\", \"passed\": true}, {\"check\": \"regression 7\", \"actual\": \"0\", \"expected\": \"0\", \"passed\": true}, {\"check\": \"regression 8\", \"actual\": \"7\", \"expected\": \"14\", \"passed\": false}, {\"check\": \"variable density mass\", \"actual\": \"2\", \"expected\": \"2\", \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":43.062,"exit_code":0,"observations":[{"actual":"11/2","check":"regression 1","expected":"11/2","passed":true},{"actual":"2","check":"regression 2","expected":"2","passed":true},{"actual":"8","check":"regression 3","expected":"8","passed":true},{"actual":"0","check":"regression 4","expected":"0","passed":true},{"actual":"0","check":"regression 5","expected":"0","passed":true},{"actual":"0","check":"regression 6","expected":"0","passed":true},{"actual":"0","check":"regression 7","expected":"0","passed":true},{"actual":"14","check":"regression 8","expected":"14","passed":true},{"actual":"2","check":"variable density mass","expected":"2","passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression 1\", \"actual\": \"11/2\", \"expected\": \"11/2\", \"passed\": true}, {\"check\": \"regression 2\", \"actual\": \"2\", \"expected\": \"2\", \"passed\": true}, {\"check\": \"regression 3\", \"actual\": \"8\", \"expected\": \"8\", \"passed\": true}, {\"check\": \"regression 4\", \"actual\": \"0\", \"expected\": \"0\", \"passed\": true}, {\"check\": \"regression 5\", \"actual\": \"0\", \"expected\": \"0\", \"passed\": true}, {\"check\": \"regression 6\", \"actual\": \"0\", \"expected\": \"0\", \"passed\": true}, {\"check\": \"regression 7\", \"actual\": \"0\", \"expected\": \"0\", \"passed\": true}, {\"check\": \"regression 8\", \"actual\": \"14\", \"expected\": \"14\", \"passed\": true}, {\"check\": \"variable density mass\", \"actual\": \"2\", \"expected\": \"2\", \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}