Non-abelian almost totally branched coverings over the platonic maps
نویسندگان
چکیده
منابع مشابه
Regular Cyclic Coverings of the Platonic Maps
The Möbius-Kantor map {4 + 4, 3} [CMo, §8.8, 8.9] is a regular orientable map of type {8, 3} and genus 2. It is a 2-sheeted covering of the cube {4, 3}, branched over the centers of its six faces, each of which lifts to an octagonal face. Its (orientation-preserving) automorphism group is isomorphic to GL2(3), a double covering of the automorphism group PGL2(3) ∼= S4 of the cube. The aim of thi...
متن کاملCohomological Constructions of Regular Cyclic Coverings of the Platonic Maps
A Platonic map is a regular map M on the sphere S. Following [CMo] we say that M has type {n,m} if it has n-gonal faces and the vertices have valency m; since these parameters determine a Platonic map uniquely, one can unambiguously write M = {n,m}. As one must have 0 ≤ (m − 2)(n − 2) < 4, there are precisely the possibilities M = {n, 2} (dihedron), M = {2,m} (hosohedron), M = {3, 3} (tetrahedr...
متن کاملEnumerating branched orientable surface coverings over a non-orientable surface
The isomorphism classes of several types of graph coverings of a graph have been enumerated by many authors [M. Hofmeister, Graph covering projections arising from finite vector space over finite fields, Discrete Math. 143 (1995) 87–97; S. Hong, J.H. Kwak, J. Lee, Regular graph coverings whose covering transformation groups have the isomorphism extention property, Discrete Math. 148 (1996) 85–1...
متن کاملEnumerating branched coverings over surfaces with boundaries
The number of nonisomorphic n-fold branched coverings over a given surface with a boundary is determined by the number of nonisomorphic n-fold graph coverings over a suitable bouquet of circles. A similar enumeration can be done for regular branched coverings. Some explicit formulae for enumerations are also obtained. © 2003 Elsevier Ltd. All rights reserved. MSC 2000: 05C10; 05C30; 57M12
متن کاملOn Extensions of Primary Almost Totally Projective Abelian Groups
Suppose G is a subgroup of the reduced abelian p-group A. The following two dual results are proved: (∗) If A/G is countable and G is an almost totally projective group, then A is an almost totally projective group. (∗∗) If G is countable and nice in A such that A/G is an almost totally projective group, then A is an almost totally projective group. These results somewhat strengthen theorems du...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: European Journal of Combinatorics
سال: 2016
ISSN: 0195-6698
DOI: 10.1016/j.ejc.2015.04.008