The main results of this paper offer sufficient conditions in order that an approximate lower Hermite–Hadamard type inequality implies an approximate Jensen convexity property. The key for the proof of the main result is a Korovkin type theorem.

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

Judit Makó

Institute of Mathematics, University of Miskolc, 3515 Miskolc-Egyetemváros, Hungary

matjudit@uni-miskolc.hu

Attila Házy

Institute of Mathematics, University of Miskolc, 3515 Miskolc-Egyetemváros, Hungary

matha@uni-miskolc.hu
  1. F. Altomare, M. Campiti: Korovkin-type Approximation Theory and its Applications, de Gruyter Studies in Mathematics 17, Walter de Gruyter, Berlin, (1994).https://doi.org/10.1515/9783110884586Google Scholar
  2. M. Bessenyei: Hermite–Hadamard-type inequalities for generalized convex functions, JIPAM, J. Inequal. Pure Appl. Math. 9(3), Article 63 (2008) 51 pp.Google Scholar
  3. M. Bessenyei, Zs. Páles: Hadamard-type inequalities for generalized convex functions, Math. Inequal. Appl. 6(3) (2003) 379–392.https://doi.org/10.7153/mia-06-35Google Scholar
  4. M. Bessenyei, Zs. Páles: Characterizations of convexity via Hadamard’s inequality, Math. Inequal. Appl. 9(1) (2006) 53–62.https://doi.org/10.7153/mia-09-06Google Scholar
  5. J. Hadamard: Étude sur les propriétés des fonctions entières et en particulier d’une fonction considérée par Riemann, J. Math. Pures Appl. 58 (1893) 171–215.Google Scholar
  6. A. Házy, Zs. Páles: On a certain stability of the Hermite–Hadamard inequality, Proc. R. Soc. Lond., Ser. A, Math. Phys. Eng. Sci. 465(2102) (2009) 571–583.https://doi.org/10.1098/rspa.2008.0291Google Scholar
  7. D. H. Hyers, S. M. Ulam: Approximately convex functions, Proc. Amer. Math. Soc. 3 (1952) 821–828.https://doi.org/10.1090/S0002-9939-1952-0049962-5Google Scholar
  8. P. P. Korovkin: On convergence of linear positive operators in the space of continuous functions, Dokl. Akad. Nauk SSSR (N.S.) 90 (1953) 961–964.Google Scholar
  9. M. Kuczma: An Introduction to the Theory of Functional Equations and Inequalities, Prace Naukowe Uniwersytetu Śląskiego w Katowicach 489, Uniwersytet Śląski, Państwowe Wydawnictwo Naukowe, Warszawa (1985).Google Scholar
  10. J. Makó, Zs. Páles: Approximate convexity of Takagi type functions, J. Math. Anal. Appl. 369 (2010) 545–554.https://doi.org/10.1016/j.jmaa.2010.03.063Google Scholar
  11. J. Makó, Zs. Páles: Approximate Hermite–Hadamard type inequalities for approximately convex functions, Math. Inequal. Appl. 16 (2013) 507–526.https://doi.org/10.7153/mia-16-37Google Scholar
  12. J. Makó, Zs. Páles: Implications between approximate convexity properties and approximate Hermite–Hadamard inequalities, Cent. Eur. J. Math. 10 (2012) 1017–1041.https://doi.org/10.2478/s11533-012-0027-5Google Scholar
  13. J. Makó, Zs. Páles: Korovkin type theorems and approximate Hermite–Hadamard inequalities, J. Approx. Theory 8 (2012) 1111–1142.https://doi.org/10.1016/j.jat.2012.05.010Google Scholar
  14. J. Makó, Zs. Páles: On approximately convex Takagi type functions, Proc. Amer. Math. Soc. 6 (2013) 2069–2080.https://doi.org/10.1090/S0002-9939-2013-11486-3Google Scholar
  15. J. Makó, Zs. Páles: On ϕ-convexity, Publ. Math. 80 (2012) 107–126.https://doi.org/10.5486/PMD.2012.4930Google Scholar
  16. D. S. Mitrinović, I. B. Lacković: Hermite and convexity, Aequationes Math. 28 (1985) 229–232.https://doi.org/10.1007/BF02189414Google Scholar
  17. C. T. Ng, K. Nikodem: On approximately convex functions, Proc. Amer. Math. Soc. 118(1) (1993) 103–108.https://doi.org/10.1090/S0002-9939-1993-1159176-XGoogle Scholar
  18. C. P. Niculescu, L.-E. Persson: Old and new on the Hermite-Hadamard inequality, Real Anal. Exch. 29(2) (2003–04) 663–685.https://doi.org/10.14321/realanalexch.29.2.0663Google Scholar
  19. C. P. Niculescu, L.-E. Persson: Convex Functions and Their Applications. A Contemporary Approach, CMS Books in Mathematics 23, Springer, New York (2006).https://doi.org/10.1007/0-387-31077-0Google Scholar
  20. K. Nikodem, T. Riedel, P. K. Sahoo: The stability problem of the Hermite-Hadamard inequality, Math. Inequal. Appl. 10(2) (2007) 359–363.https://doi.org/10.7153/mia-10-33Google Scholar

J. Makó, A. Házy. “On Approximate Hermite-Hadamard Type Inequalities.” Journal of Convex Analysis 24 (2017), No. 2, 349–363. https://doi.org/10.68381/jca24024