International Journal of Mathematics and Mathematical Sciences
Volume 2006 (2006), Article ID 79858, 8 pages
Collapsing along monotone poset maps
Institute of Theoretical Computer Science, Swiss Federal Institute of Technology Zurich, Zurich 8092, Switzerland
Received 21 March 2005; Revised 13 September 2005; Accepted 12 February 2006
Copyright © 2006 Dmitry N. Kozlov. 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.
We introduce the notion of nonevasive reduction and show that for any monotone poset map , the simplicial complex NE-reduces to , for any .
As a corollary, we prove that for any order-preserving map satisfying , for any
, the simplicial complex collapses to . We also obtain a generalization of Crapo's closure theorem.