{ "id": "0809.1691", "version": "v1", "published": "2008-09-09T23:52:55.000Z", "updated": "2008-09-09T23:52:55.000Z", "title": "Completely multiplicative functions taking values in $\\{-1,1\\}$", "authors": [ "Peter Borwein", "Stephen K. K. Choi", "Michael Coons" ], "categories": [ "math.NT" ], "abstract": "Define {\\em the Liouville function for $A$}, a subset of the primes $P$, by $\\lambda_{A}(n) =(-1)^{\\Omega_A(n)}$ where $\\Omega_A(n)$ is the number of prime factors of $n$ coming from $A$ counting multiplicity. For the traditional Liouville function, $A$ is the set of all primes. Denote $$L_A(n):=\\sum_{k\\leq n}\\lambda_A(n)\\quad{and}\\quad R_A:=\\lim_{n\\to\\infty}\\frac{L_A(n)}{n}.$$ We show that for every $\\alpha\\in[0,1]$ there is an $A\\subset P$ such that $R_A=\\alpha$. Given certain restrictions on $A$, asymptotic estimates for $\\sum_{k\\leq n}\\lambda_A(k)$ are also given. With further restrictions, more can be said. For {\\em character--like functions} $\\lambda_p$ ($\\lambda_p$ agrees with a Dirichlet character $\\chi$ when $\\chi(n)\\neq 0$) exact values and asymptotics are given; in particular $$\\quad\\sum_{k\\leq n}\\lambda_p(k)\\ll \\log n.$$ Within the course of discussion, the ratio $\\phi(n)/\\sigma(n)$ is considered.", "revisions": [ { "version": "v1", "updated": "2008-09-09T23:52:55.000Z" } ], "analyses": { "subjects": [ "11N25", "11N37" ], "keywords": [ "multiplicative functions", "traditional liouville function", "exact values", "dirichlet character", "asymptotic estimates" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2008arXiv0809.1691B" } } }