{ "id": "2210.08653", "version": "v1", "published": "2022-10-16T22:40:30.000Z", "updated": "2022-10-16T22:40:30.000Z", "title": "A note on positive association", "authors": [ "Jeff Kahn" ], "categories": [ "math.PR" ], "abstract": "We show that if ${\\mathcal A},{\\mathcal B},{\\mathcal C}$ are increasing subsets of $\\Omega:=\\{0,1\\}^n$ with ${\\mathcal A}\\neq\\emptyset$, then with respect to any product probability measure on $\\Omega$, \\[ \\mbox{if each of the pairs $\\{{\\mathcal A}\\cap{\\mathcal B},{\\mathcal C}\\}$, $\\{{\\mathcal A}\\cap {\\mathcal C},{\\mathcal A}\\}$ is independent, then ${\\mathcal B}$ and ${\\mathcal C}$ are independent.} \\] This implies an answer to a motivating question of J. Steif, and is related to a basic, still open variant of that question, and to a well-known conjecture of S. Sahi.", "revisions": [ { "version": "v1", "updated": "2022-10-16T22:40:30.000Z" } ], "analyses": { "subjects": [ "60C05" ], "keywords": [ "positive association", "product probability measure", "well-known conjecture", "open variant", "independent" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }