16,588 research outputs found
Classification of regular maps of negative prime Euler characteristic
We give a classification of all regular maps on nonorientable surfaces with a negative odd prime Euler characteristic (equivalently, on nonorientable surfaces of genus where is an odd prime). A consequence of our classification is that there are no regular maps on nonorientable surfaces of genus where is a prime such that (mod ) and
Degree-regular triangulations of the double-torus
A connected combinatorial 2-manifold is called degree-regular if each of its
vertices have the same degree. A connected combinatorial 2-manifold is called
weakly regular if it has a vertex-transitive automorphism group. Clearly, a
weakly regular combinatorial 2-manifold is degree-regular and a degree-regular
combinatorial 2-manifold of Euler characteristic - 2 must contain 12 vertices.
In 1982, McMullen et al. constructed a 12-vertex geometrically realized
triangulation of the double-torus in \RR^3. As an abstract simplicial
complex, this triangulation is a weakly regular combinatorial 2-manifold. In
1999, Lutz showed that there are exactly three weakly regular orientable
combinatorial 2-manifolds of Euler characteristic - 2. In this article, we
classify all the orientable degree-regular combinatorial 2-manifolds of Euler
characteristic - 2. There are exactly six such combinatorial 2-manifolds. This
classifies all the orientable equivelar polyhedral maps of Euler characteristic
- 2.Comment: 13 pages. To appear in `Forum Mathematicum
Classification and Galois conjugacy of Hamming maps
We show that for each d>0 the d-dimensional Hamming graph H(d,q) has an
orientably regular surface embedding if and only if q is a prime power p^e. If
q>2 there are up to isomorphism \phi(q-1)/e such maps, all constructed as
Cayley maps for a d-dimensional vector space over the field of order q. We show
that for each such pair d, q the corresponding Belyi pairs are conjugate under
the action of the absolute Galois group, and we determine their minimal field
of definition. We also classify the orientably regular embedding of merged
Hamming graphs for q>3
Topological types of real regular jacobian elliptic surfaces
We present the topological classification of real parts of real regular
elliptic surfaces with a real section.Comment: 17 pages, 7 figures, to appear in Geometriae Dedicat
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