International Journal of Mathematics and Mathematical Sciences
Volume 2005 (2005), Issue 1, Pages 91-97

Image sets of folding surfaces

Ana M. d'Azevedo Breda

Department of Mathematics, University of Aveiro, Aveiro 3810-193, Portugal

Received 27 January 2004

Copyright © 2005 Ana M. d'Azevedo Breda. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Isometric foldings are a special class of length-preserving maps of Riemannian manifolds and were initially studied by S. Robertson. For an explanation of their topological and combinatorial properties, see the related works of Ana Breda, Altino Santos, M. El-Ghoul, and E. M. Elkholy. Here, we explore some properties of the singular set and describe the image set of planar, spherical, and hyperbolic foldings.