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Journal of Convex Analysis 28 (2021), No. 4, 1193--1210 Copyright Heldermann Verlag 2021 On k-Strong Convexity in Banach Spaces M. Veena Sangeetha Dept. of Mathematics, Indian Institute of Technology, Kharagpur, India veena176@gmail.com M. Radhakrishnan Ramanujan Inst. for Advanced Study in Mathematics, University of Madras, India and: Dept. of Mathematics, SRM University, Andra Pradesh, India radhariasm@gmail.com Samir Kar Dept. of Mathematics, Indian Institute of Technology, Madras, India and: Dept. of Mathematics, Indian Institute of Technology, Jammu, India msamirkar@gmail.com We introduce and study the notion of k-strong convexity in Banach spaces. It is a generalization of the notion of strong convexity first studied by Fan and Glicksberg. A Banach space is said to be k-strongly convex if it is reflexive, k-strictly convex and has the Kadec-Klee property. We use the idea of k-dimensional diameter to give several characterizations of k-strong convexity. Further, we study k-strict convexity and k-strong convexity in some products of Banach spaces. Finally, we give characterizations of k-uniform convexity that distinguish it from k-strong convexity. Keywords: k-strict convexity, k-strong convexity, k-uniform convexity, property k-UC, monotone norm, product space. MSC: 46B20, 41A65. [ Fulltext-pdf (162 KB)] for subscribers only. |