We present some geometric and approximation theoretic characterizations of locally uniform convex, compactly locally uniformly convex, nearly uniformly convex, compactly uniformly convex and uniformly convex Banach spaces. The approximation theoretic characterizations of compactly locally uniformly convex spaces presented in this paper provide some answers to a question posed by F. Deutsch and J. Lambert in their paper On continuity of metric projections, J. Approx. Theory 29 (1980) 116–131.

Contact details are reproduced from the original publication and may be historical.

P. Shunmugaraj

Dept. of Mathematics and Statistics, Indian Institute of Technology, Kanpur 208016, India

psraj@iitk.ac.in

Vamsinadh Thota

Dept. of Mathematics and Statistics, Indian Institute of Technology, Kanpur 208016, India

vamst@iitk.ac.in
  1. A. Aizpuru, F. J. Garcia-Pacheco: Some questions about rotundity and renormings in Banach spaces, J. Aust. Math. Soc. 79 (2005) 131–140.https://doi.org/10.1017/S144678870000937XGoogle Scholar
  2. J. Banaś, K. Goebel: Measures of Non-Compactness in Banach Spaces, Lecture Notes Pure Appl. Math. 60, Marcel Dekker, New York (1980).Google Scholar
  3. P. Bandyopadhyay, Y. Li, B.-L. Lin, D. Narayana: Proximinality in Banach spaces, J. Math. Anal. Appl. 341 (2008) 309–317.https://doi.org/10.1016/j.jmaa.2007.10.024Google Scholar
  4. A. K. Chakrabarty, P. Shunmugaraj, C. Zălinescu: Continuity properties for the subdifferential and ε-subdifferential of a convex function and its conjugate, J. Convex Analysis 14 (2007) 479–514.https://doi.org/10.68381/jca14031Google Scholar
  5. S. Cobzas: Geometric properties of Banach spaces and the existence of nearest and farthest points, Abstr. Appl. Anal. 3 (2005) 259–285.https://doi.org/10.1155/AAA.2005.259Google Scholar
  6. F. Deutsch, J. Lambert: On continuity of metric projections, J. Approx. Theory 29 (1980) 116–131.https://doi.org/10.1016/0021-9045(80)90110-0Google Scholar
  7. S. J. Dilworth, D. Kutzarova, N. L. Randrianarivony, J. P. Revalski, N. V. Zhivkov: Compactly uniformly convex spaces and property (β) of Rolewich, J. Math. Anal. Appl. 402 (2013) 297–307.https://doi.org/10.1016/j.jmaa.2013.01.039Google Scholar
  8. S. Dutta, P. Shunmugaraj: Strong proximinality of closed convex sets, J. Approx. Theory 163 (2011) 547–553.https://doi.org/10.1016/j.jat.2011.01.001Google Scholar
  9. S. Dutta, P. Shunmugaraj, V. Thota: Uniform strong proximinality and continuity of metric projection, J. Convex Analysis 24(4) (2017) 1263–1279.https://doi.org/10.68381/jca24072Google Scholar
  10. K. Fan, I. Glicksberg: Some geometric properties of the spheres in a normed linear space, Duke Math. J. 25 (1958) 553–568.https://doi.org/10.1215/S0012-7094-58-02550-XGoogle Scholar
  11. J. R. Giles, D. A. Gregory, B. Sims: Geometrical implications of upper semicontinuity of the duality mapping on a Banach space, Pacific J. Math. 79 (1978) 99–109.https://doi.org/10.2140/pjm.1978.79.99Google Scholar
  12. J. R. Giles, W. B. Moors: A continuity property related to Kuratowski’s index of non-compactness, its relevance to the drop property and its implications for differentiabilty theory, J. Math. Anal. Appl. 178 (1993) 247–268.https://doi.org/10.1006/jmaa.1993.1304Google Scholar
  13. A. J. Guirao, V. Montesinos: A note in approximative compactness and continuity of metric projection in Banach spaces, J. Convex Analysis 18 (2011) 397–401.https://doi.org/10.68381/jca18023Google Scholar
  14. R. Huff: Banach spaces which are nearly uniformly convex, Rocky Mountain J. Math. 10 (1980) 743–749.https://doi.org/10.1216/RMJ-1980-10-4-743Google Scholar
  15. D. N. Kutzarova, P. L. Papini: On a characterization of property (β) and LUR, Boll. Un. Mat. Ital. (A)(7) 6 (1992) 209–214.Google Scholar
  16. R. E. Megginson: An Introduction to Banach Space Theory, Springer, New York (1998).https://doi.org/10.1007/978-1-4612-0603-3Google Scholar
  17. R. E. Megginson: The semi-Kadec-Klee condition and nearest point properties of sets in normed linear spaces, Ph.D. Thesis, University of Illinois at Urbana-Champaign (1984).Google Scholar
  18. V. Montesinos, J. R. Torregrosa: Some properties which generalize uniform rotundity of Banach spaces, Arch. Math. 59 (1992) 457–467.https://doi.org/10.1007/BF01236041Google Scholar
  19. B. B. Panda, O. P. Kapoor: Approximative compactness and continuity of metric projections, Bull. Austral. Math. Soc. 11 (1974) 47–55.https://doi.org/10.1017/S0004972700043628Google Scholar
  20. B. B. Panda, O. P. Kapoor: A generalization of local uniform convexity of the norm, J. Math. Anal. Appl. 52 (1975) 300–308.https://doi.org/10.1016/0022-247X(75)90098-0Google Scholar
  21. J. P. Revalski, N. V. Zhivkov: Best approximation problems in compactly uniformly rotund spaces, J. Convex Analysis 19 (2012) 1153–1166.https://doi.org/10.68381/jca19061Google Scholar
  22. J. P. Revalski, N. V. Zhivkov: Small sets in best approximation theory, J. Global Optim. 50 (2011) 77–91.https://doi.org/10.1007/s10898-010-9621-xGoogle Scholar
  23. S. Rolewicz: On ∆-uniform convexity and drop property, Studia Math. 87 (1987) 181–191.https://doi.org/10.4064/sm-87-2-181-191Google Scholar
  24. P. Shunmugaraj: Convergence of slices, geometric aspects in Banach spaces and proximinality, Nonlinear Analysis 61–107, part of Trends in Mathematics, Springer, New Delhi (2014).https://doi.org/10.1007/978-81-322-1883-8_3Google Scholar
  25. P. Shunmugaraj, V. Thota: Uniform convexity, strong convexity and property UC, J. Math. Anal. Appl. 446 (2017) 1769–1775.https://doi.org/10.1016/j.jmaa.2016.10.001Google Scholar
  26. L. P. Vlasov: Approximative properties of sets in normed linear spaces, Russian Math. Surveys 28 (1973) 1–66.https://doi.org/10.1070/RM1973v028n06ABEH001624Google Scholar
  27. Z. Zhang, C. Liu, Y. Zhou: Some examples concerning proximinality in Banach spaces, J. Approx. Theory 200 (2015) 136–143.https://doi.org/10.1016/j.jat.2015.06.002Google Scholar

P. Shunmugaraj, V. Thota. “Some Geometric and Proximinality Properties in Banach Spaces.” Journal of Convex Analysis 25 (2018), No. 4, 1139–1158. https://doi.org/10.68381/jca25072