{ "id": "1412.0392", "version": "v1", "published": "2014-12-01T09:33:02.000Z", "updated": "2014-12-01T09:33:02.000Z", "title": "On the equation $\\mathbf{m=xyzw}$ with $\\mathbf{x\\leqslant y\\leqslant z\\leqslant w}$ in positive integers", "authors": [ "Madjid Mirzavaziri", "Daniel Yaqubi" ], "categories": [ "math.CO" ], "abstract": "As a well-known enumerative problem, the number of solutions of the equation $m=m_1+...+m_k$ with $m_1\\leqslant...\\leqslant m_k$ in positive integers is $\\Pi(m,k)=\\sum_{i=0}^k\\Pi(m-k,i)$ and $\\Pi$ is called the additive partition function. In this paper, we give a recursive formula for the so-called multiplicative partition function $\\mu_1(m,k):=$ the number of solutions of the equation $m=m_1... m_k$ with $m_1\\leqslant...\\leqslant m_k$ in positive integers. In particular, using an elementary proof, we give an explicit formula for the cases $k=1,2,3,4$.", "revisions": [ { "version": "v1", "updated": "2014-12-01T09:33:02.000Z" } ], "analyses": { "keywords": [ "positive integers", "well-known enumerative problem", "additive partition function", "multiplicative partition function", "elementary proof" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2014arXiv1412.0392M" } } }