Regular abelian coverings of cyclic hypermaps


Maureemootoo, Dawn Irene (2000) Regular abelian coverings of cyclic hypermaps. University of Southampton, Department of Mathematics, Doctoral Thesis , 165pp.

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Description/Abstract

The foundations of this work lie in the use of representation theory
to find lattices of regular hypermaps H arising as elementary abelian
coverings of some regular hypermap Ji such that Aut(Tt) = CR. It is
assumed that Aut(7f) = C™ X CR a spUt extension of an elementary
abelian group with cyclic complement. Examples of this situation are
found in [2] where regular orientable imbeddings of the complete graph
Kq, q = pe with p a prime integer, were classified and enumerated. Initial
investigations are of maps obtained from regular orientable imbeddings
of certain highly symmetrical subgraphs Kq of Kq. Results pertaining
to the number and valency of vertices, edges, faces, Petrie polygons, the
genus, the automorphism group and reflexibility are found to be similar
to those obtained in [2]. Subsequently, a description is given of the
general construction. Determination of the lattice of coverings H of H
is found to be dependent upon the signature of the map-subgroup T of
H. Results are obtained for the cases where Tab is a torsion group and
where F"6 is a free abelian group. Hypermap operations induced by outer
automorphisms of the triangle group A(R, R, oo) are also considered
here. The hypermaps are regular of type (R, R,p) and, once again, have
automorphism group C™ XI CR. It was found that when n = 1 these
hypermaps lie in a single orbit under the group of hypermap operations,
whilst when n = 2 they have orbit length <p{R)2 in case R\p - 1 and
length (p(R)2/2 otherwise.

Item Type: Thesis (Doctoral)
Subjects: Q Science > QA Mathematics
Divisions: University Structure - Pre August 2011 > School of Mathematics
ePrint ID: 50625
Date Deposited: 19 Mar 2008
Last Modified: 27 Mar 2014 18:33
URI: http://eprints.soton.ac.uk/id/eprint/50625

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