{ "id": "1503.08359", "version": "v1", "published": "2015-03-28T22:15:26.000Z", "updated": "2015-03-28T22:15:26.000Z", "title": "On The Number Of Topologies On A Finite Set", "authors": [ "Muhammet Yasir Kızmaz" ], "categories": [ "math.NT" ], "abstract": "We denote the number of distinct topologies which can be defined on the set $X$ with $n$ elements by $T(n)$. Similarly, $T_0(n)$ denotes the number of distinct $T_0$ topologies on the set $X$. In the present paper, we prove that for any prime $p$, $T(p^k)\\equiv k+1 \\ mod \\ p$, and that for each non-negative integer $n$ there exists a unique $k$ such that $T(p+n)\\equiv k$. We calculate $k$ for $n=1,2,3,4$. We give an elementary proof for a result of Z.I.Borevich to the effect that $T_0(p+n)\\equiv T_0(n+1) \\ mod \\ p$.", "revisions": [ { "version": "v1", "updated": "2015-03-28T22:15:26.000Z" } ], "analyses": { "subjects": [ "11B50" ], "keywords": [ "finite set", "distinct topologies", "elementary proof", "non-negative integer" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }