Abstract and Applied Analysis
Volume 2008 (2008), Article ID 968478, 8 pages
Research Article

Existence Results for Generalized Vector Equilibrium Problems with Multivalued Mappings via KKM Theory

A. P. Farajzadeh,1,2 A. Amini-Harandi,3 and D. O'Regan4

1Department of Mathematics, School of Science, Razi University, P.O. Box 67149-67346, Kermanshah, Iran
2Center for Research in Mathematics and Physics, School of Mathematics, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5746, Tehran, Iran
3Department of Mathematics, Faculty of Basic Sciences, University of Shahrekord, P.O. Box 88186-34141, Shahrekord, Iran
4Department of Mathematics, College of Arts, Social Sciences, & Celtic Studies, National University of Ireland, Galway, Ireland

Received 6 August 2008; Accepted 21 October 2008

Academic Editor: Paul Eloe

Copyright © 2008 A. P. Farajzadeh et al. 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 first define upper sign continuity for a set-valued mapping and then we consider two types of generalized vector equilibrium problems in topological vector spaces and provide sufficient conditions under which the solution sets are nonempty and compact. Finally, we give an application of our main results. The paper generalizes and improves results obtained by Fang and Huang in (2005).