Sandwich type results for m-convex real functions



Abstract

We establish necessary and sufficient conditions allowing separation of pair of real functions by an m-convex and by an m-affine function. Some examples and a geometric interpretation of m-convexity of a function is exhibited, as well as a Jensen’s inequality for this kind of function.


Keywords

m-convex function; m-affine function; Jensen type inequality; sandwich theorem

1. K. Baron, J. Matkowski, and K. Nikodem, A sandwich with convexity, Math. Pannon. 5 (1994), no. 1, 139–144.
2. M. Bracamonte, J. Giménez, and J. Medina, Sandwich theorem for reciprocally strongly convex functions, Rev. Colombiana Mat. 52 (2018), no. 2, 171–184.
3. M. Kuczma, An Introduction to the Theory of Functional Equations and Inequalities. Cauchy’s Equation and Jensen’s Inequality, Second edition, Birkhäuser Verlag, Basel, 2009.
4. T. Lara, J. Matkowski, N. Merentes, R. Quintero, and M. Wróbel, A generalization of m-convexity and a sandwich theorem, Ann. Math. Sil. 31 (2017), 107–126.
5. T. Lara, N. Merentes, Z. Páles, R. Quintero, and E. Rosales, On m-convexity on real linear spaces, UPI Journal of Mathematics and Biostatistics 1 (2018), no. 2, JMB8, 16 pp.
6. T. Lara, N. Merentes, R. Quintero, and E. Rosales, On m-concave functions on real linear spaces, Bol. Asoc. Mat. Venez. 23 (2016), no. 2, 131–137.
7. T. Lara, N. Merentes, R. Quintero, and E. Rosales, On m-convexity of set-valued functions, Adv. Oper. Theory 4 (2019), no. 4, 767–783.
8. T. Lara, N. Merentes, E. Rosales, and A. Tineo, Properties and characterizations of convex functions on time scales, Ann. Math. Sil. 32 (2018), 237–245.
9. T. Lara and E. Rosales, Strongly convex functions on time scales, UPI Journal of Mathematics and Biostatistics 1 (2018), no. 2, JMB9, 10 pp.
10. T. Lara and E. Rosales, Log m-convex functions, Moroc. J. of Pure and Appl. Anal. (MJPAA) 5 (2019), no. 2, 117–124.
11. T. Lara, E. Rosales, and J.L. Sánchez, New properties of m-convex functions, Int. J. Math. Anal. (Ruse) 9 (2015), no. 15, 735–742.
12. J. Matkowski and M. Wróbel, Sandwich theorem for m-convex functions, J. Math. Anal. Appl. 451 (2017), no. 2, 924–930.
13. N. Merentes and K. Nikodem, Remarks on strongly convex functions, Aequationes. Math. 80 (2010), no. 1-2, 193–199.
14. C.P. Niculescu and L.-E. Persson, Convex Functions and Their Applications. A Contemporary Approach, CMS Books in Mathematics, 23, Springer, New York, 2006.
15. K. Nikodem and S. Wąsowicz, A sandwich theorem and Hyers-Ulam stability of affine functions, Aequationes Math. 49 (1995), no. 1-2, 160–164.
16. A. Olbryś, On separation by h-convex functions, Tatra Mt. Math. Publ. 62 (2015), 105–111.
17. A.W. Roberts and D.E. Varberg, Convex Functions, Pure and Applied Mathematics, 57, Academic Press, New York, 1973.
18. E. Sadowska, A sandwich with convexity for set-valued functions, Math. Pannon. 7 (1996), no. 1, 163–169.
19. G. Toader, Some generalizations of the convexity, in: I. Murusciac and W.W. Breckner (eds.), Proceedings of the Colloquium on Approximation and Optimization, Univ. Cluj-Napoca, Cluj-Napoca, 1985, pp. 329–338.
20. G. Toader, On a generalization of the convexity, Mathematica (Cluj) 30(53) (1988), no. 1, 83–87.
21. F.A. Valentine, Convex Sets, McGraw-Hill Series in Higher Mathematics, McGraw-Hill Book Co., New York, 1964.
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Published : 2021-05-26


LaraT., & RosalesE. (2021). Sandwich type results for m-convex real functions. Annales Mathematicae Silesianae, 35(2), 250-259. Retrieved from https://journals.us.edu.pl/index.php/AMSIL/article/view/13450

Teodoro Lara  tlara@ula.ve
Departamento de Física y Matemáticas, Universidad de los Andes, Núcleo “Rafael Rangel”, Venezuela  Venezuela, Bolivarian Republic of
https://orcid.org/0000-0002-3028-1961
Edgar Rosales 
Departamento de Física y Matemáticas, Universidad de los Andes, Núcleo “Rafael Rangel”, Venezuela  Venezuela, Bolivarian Republic of



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