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Hyperbolic polygons and NEC groups


Etayo Gordejuela, J. Javier and Martínez, Ernesto (1988) Hyperbolic polygons and NEC groups. Mathematical Proceedings of the Cambridge Philosophical Society, 104 . pp. 261-272. ISSN 0305-0041

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Beardon gave a procedure for constructing a polygon with prescribed angles. For each ordered set of angles Beardon's polygon is unique up to congruence. The polygon obtained this way has an inscribed circle. It is possible to obtain by means of these polygons a fundamental region for a non-Euclidean crystallographic (NEC) group with a given signature having equal angles in each of the cycles. In [5] the minimal number of sides of a convex fundamental region of an NEC group is calculated, and regions are explicitly obtained achieving the bound.

Item Type:Article
Uncontrolled Keywords:Moduli of Riemann surfaces, Teichmüller theory; Structure of modular groups and generalizations; arithmetic groups; Riemann surfaces; Hyperbolic and elliptic geometries (general) and generalizations; Topology of E 2 , 2 -manifolds
Subjects:Sciences > Mathematics > Algebraic geometry
ID Code:15768

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Deposited On:26 Jun 2012 11:19
Last Modified:06 Feb 2014 10:31

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