{ "id": "1901.07135", "version": "v1", "published": "2019-01-22T01:10:16.000Z", "updated": "2019-01-22T01:10:16.000Z", "title": "Regular maps of order $2$-powers", "authors": [ "Dong-Dong Hou", "Yan-Quan Feng", "Young Soo Kwon" ], "comment": "16pages", "categories": [ "math.CO" ], "abstract": "In this paper, we consider the possible types of regular maps of order $2^n$, where the order of a regular map is the order of automorphism group of the map. For $n \\le 11$, M. Conder classified all regular maps of order $2^n$. It is easy to classify regular maps of order $2^n$ whose valency or covalency is $2$ or $2^{n-1}$. So we assume that $n \\geq 12$ and $2\\leq s,t\\leq n-2$ with $s\\leq t$ to consider regular maps of order $2^n$ with type $\\{2^s, 2^t\\}$. We show that for $s+t\\leq n$ or for $s+t>n$ with $s=t$, there exists a regular map of order $2^n$ with type $\\{2^s, 2^t\\}$, and furthermore, we classify regular maps of order $2^n$ with types $\\{2^{n-2},2^{n-2}\\}$ and $\\{2^{n-3},2^{n-3}\\}$. We conjecture that, if $s+t>n$ with $s