Fixed Point Theory and Applications
Volume 2006 (2006), Article ID 68513, 9 pages

Coincidence classes in nonorientable manifolds

Daniel Vendrúscolo

Departamento de Matemútica, Universidade Federal de Sáo Carlos, Rodovia Washington Luiz, Km 235, CP 676, Sáo Carlos 13565-905, SP, Brazil

Received 15 September 2004; Revised 20 April 2005; Accepted 21 July 2005

Copyright © 2006 Daniel Vendrúscolo. 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 study Nielsen coincidence theory for maps between manifolds of same dimension regardless of orientation. We use the definition of semi-index of a class, review the definition of defective classes, and study the occurrence of defective root classes. We prove a semi-index product formula for lifting maps and give conditions for the defective coincidence classes to be the only essential classes.