Compact hyperbolic tetrahedra with non-obtuse dihedral angles.

Roeder, Roland K.W.. "Compact hyperbolic tetrahedra with non-obtuse dihedral angles.." Publicacions Matemàtiques 50.1 (2006): 211-227. <http://eudml.org/doc/41578>.

@article{Roeder2006,
abstract = {Given a combinatorial description C of a polyhedron having E edges, the space of dihedral angles of all compact hyperbolic polyhedra that realize C is generally not a convex subset of RE. If C has five or more faces, Andreev's Theorem states that the corresponding space of dihedral angles AC obtained by restricting to non-obtuse angles is a convex polytope. In this paper we explain why Andreev did not consider tetrahedra, the only polyhedra having fewer than five faces, by demonstrating that the space of dihedral angles of compact hyperbolic tetrahedra, after restricting to non-obtuse angles, is non-convex. Our proof provides a simple example of the method of continuity, the technique used in classification theorems on polyhedra by Alexandrow, Andreev, and Rivin-Hodgson.},
author = {Roeder, Roland K.W.},
journal = {Publicacions Matemàtiques},
keywords = {Convexidad; Geometría hiperbólica; Poliedro; Tetraedros},
language = {eng},
number = {1},
pages = {211-227},
title = {Compact hyperbolic tetrahedra with non-obtuse dihedral angles.},
url = {http://eudml.org/doc/41578},
volume = {50},
year = {2006},
}

TY - JOUR
AU - Roeder, Roland K.W.
TI - Compact hyperbolic tetrahedra with non-obtuse dihedral angles.
JO - Publicacions Matemàtiques
PY - 2006
VL - 50
IS - 1
SP - 211
EP - 227
AB - Given a combinatorial description C of a polyhedron having E edges, the space of dihedral angles of all compact hyperbolic polyhedra that realize C is generally not a convex subset of RE. If C has five or more faces, Andreev's Theorem states that the corresponding space of dihedral angles AC obtained by restricting to non-obtuse angles is a convex polytope. In this paper we explain why Andreev did not consider tetrahedra, the only polyhedra having fewer than five faces, by demonstrating that the space of dihedral angles of compact hyperbolic tetrahedra, after restricting to non-obtuse angles, is non-convex. Our proof provides a simple example of the method of continuity, the technique used in classification theorems on polyhedra by Alexandrow, Andreev, and Rivin-Hodgson.
LA - eng
KW - Convexidad; Geometría hiperbólica; Poliedro; Tetraedros
UR - http://eudml.org/doc/41578
ER -