Different stationarity and regularity concepts for extended real-valued functions on metric spaces are considered in the paper. The properties are characterized in terms of certain local constants. A classification scheme for stationarity/regularity constants and corresponding concepts is proposed. The relations between different constants are established.
University of Ballarat, School of Information Technology and Mathematical Sciences, Research Report 2005/14. Published in Applied and Computational Mathematics 5 (2006), no.1, 79-93.