{ "id": "1407.0177", "version": "v1", "published": "2014-07-01T10:37:52.000Z", "updated": "2014-07-01T10:37:52.000Z", "title": "Finite Differences of the Logarithm of the Partition Function", "authors": [ "William Y. C. Chen", "Larry X. W. Wang", "Gary Y. B. Xie" ], "comment": "28 pages", "categories": [ "math.NT", "math.CO" ], "abstract": "Let $p(n)$ denote the partition function. DeSalvo and Pak proved that $\\frac{p(n-1)}{p(n)}\\left(1+\\frac{1}{n}\\right)> \\frac{p(n)}{p(n+1)}$ for $n\\geq 2$, as conjectured by Chen. Moreover, they conjectured that a sharper inequality $\\frac{p(n-1)}{p(n)}\\left( 1+\\frac{\\pi}{\\sqrt{24}n^{3/2}}\\right) > \\frac{p(n)}{p(n+1)}$ holds for $n\\geq 45$. In this paper, we prove the conjecture of Desalvo and Pak by giving an upper bound for $-\\Delta^{2} \\log p(n-1)$, where $\\Delta$ is the difference operator with respect to $n$. We also show that for given $r\\geq 1$ and sufficiently large $n$, $(-1)^{r-1}\\Delta^{r} \\log p(n)>0$. This is analogous to the positivity of finite differences of the partition function. It was conjectured by Good and proved by Gupta that for given $r\\geq 1$, $\\Delta^{r} p(n)>0$ for sufficiently large $n$.", "revisions": [ { "version": "v1", "updated": "2014-07-01T10:37:52.000Z" } ], "analyses": { "subjects": [ "05A20", "11B68" ], "keywords": [ "partition function", "finite differences", "conjecture", "sufficiently large", "upper bound" ], "note": { "typesetting": "TeX", "pages": 28, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2014arXiv1407.0177C" } } }