Korean J. Math. Vol. 34 No. 3 (2026) pp.393-408
DOI: https://doi.org/10.11568/kjm.2026.34.3.393

Hyers-Ulam stability of functional equations with parameters

Main Article Content

Jing Zhang
Qi Liu
Yongmo Hu
Linlin Fu
John Michael Rassias
Choonkil Park
Yongjin Li

Abstract

This paper explores the Hyers-Ulam stability of parameterized generalized Jensen additive and quadratic functional equations in \(\beta\)-homogeneous \(F\)-spaces, showing that approximately satisfying mappings have a unique exact approximating counterpart within a specific bound. The corresponding stability theorems are established with estimates. The results extend existing stability results to the parameterized case, enrich the theory of functional equations in \(\beta\)-homogeneous \(F\)-spaces, and provide a concise proof approach for similar equations.



Article Details

References

[1] C. Park and T. M. Rassias, Isometric additive mappings in generalized quasi-Banach spaces, Banach J. Math. Anal. 2 (1) (2008), 59–69. https://doi.org/10.15352/bjma/1240336274 Google Scholar

[2] D. H. Hyers, On the stability of the linear functional equation, Proc. Natl. Acad. Sci. USA 27 (4) (1941), 222–224. https://doi.org/10.1073/pnas.27.4.222 Google Scholar

[3] D. H. Hyers, G. Isac, and T. M. Rassias, Stability of Functional Equations in Several Variables, Birkhäuser, Basel (1998). https://doi.org/10.1007/978-1-4612-1790-9 Google Scholar

[4] I. El-Fassi, S. Kabbaj, and A. Charifi, Hyperstability of Cauchy–Jensen functional equations, Indag. Math. (N.S.) 27 (3) (2016), 855–867. https://doi.org/10.1016/j.indag.2016.04.001 Google Scholar

[5] F. Albiac, Nonlinear structure of some classical quasi-Banach spaces and F-spaces, J. Math. Anal. Appl. 340 (2) (2008), 1312–1325. https://doi.org/10.1016/j.jmaa.2007.09.052 Google Scholar

[6] F. Vajzović, Über das Funktional H mit der Eigenschaft: (x,y)=0 ⇒ H(x+y)+H(x−y)=2H(x)+2H(y), Glas. Mat. Ser. III 2 (22) (1967), 73–81. Google Scholar

[7] F. Skof, Proprietà locali e approssimazione di operatori, Rend. Semin. Mat. Fis. Milano 53 (1) (1983), 113–129. https://doi.org/10.1007/BF02924890 Google Scholar

[8] G. Y. Szabó, Sesquilinear orthogonally quadratic mappings, Aequationes Math. 40 (2-3) (1990), 190–200. https://doi.org/10.1007/BF02112295 Google Scholar

[9] H. Drljević, On a functional which is quadratic on A-orthogonal vectors, Publ. Inst. Math. (Beograd) (N.S.) 40 (54) (1986), 63–71. Google Scholar

[10] I. El-Fassi, Hyperstability of the generalized multi-Drygas equation in complete b-metric Abelian groups, Bull. Sci. Math. 193 (2024), 103532. https://doi.org/10.1016/j.bulsci.2024.103532 Google Scholar

[11] J. Rätz, On orthogonally additive mappings, Aequationes Math. 28 (1) (1985), 35–49. https://doi.org/10.1007/BF02189390 Google Scholar

[12] J. Xia, Q. Liu, Y. Zhou, and Y. Shen, Some studies on Euler-Lagrange quartic functional equations in β-normed spaces, J. Appl. Anal. Comput. 15 (3) (2025), 1770–1785. https://doi.org/10.11948/20240405 Google Scholar

[13] J. Sikorska, Orthogonalities and functional equations, Aequationes Math. 89 (2) (2015), 333–360. https://doi.org/10.1007/s00010-014-0288-0 Google Scholar

[14] J. Brzdęk, D. Popa, and T. M. Rassias, Ulam Type Stability, Springer, Cham (2019). https://doi.org/10.1007/978-3-030-28972-0 Google Scholar

[15] J. Sikorska, Generalized orthogonal stability of some functional equations, J. Inequal. Appl. 2006 (2006), Art. ID 12404. https://doi.org/10.1155/JIA/2006/12404 Google Scholar

[16] K. Ravi, J. M. Rassias, and R. Kodandan, Generalized Ulam-Hyers stability of an AQ-functional equation in quasi-beta-normed spaces, Math. Aeterna 1 (4) (2011), 217–236. Google Scholar

[17] C. L. Pagani and J. Rätz, Conditional functional equations and orthogonal additivity, Aequationes Math. 50 (1-2) (1995), 135–142. https://doi.org/10.1007/BF01831116 Google Scholar

[18] L. Fu, Q. Liu, and Y. Li, On the stability of orthogonally Jensen additive and quadratic functional equation, J. Math. Anal. Appl. 519 (2) (2023), 126744. https://doi.org/10.1016/j.jmaa.2022.126744 Google Scholar

[19] M. Fochi, Functional equations on A-orthogonal vectors, Aequationes Math. 38 (1) (1989), 28–40. https://doi.org/10.1007/BF01839491 Google Scholar

[20] M. S. Moslehian, On the orthogonality stability of the Pexiderized quadratic equation, J. Difference Equ. Appl. 11 (11) (2005), 999–1004. https://doi.org/10.1080/10236190500273226 Google Scholar

[21] M. S. Moslehian, On the stability of the orthogonal Pexiderized Cauchy equation, J. Math. Anal. Appl. 318 (1) (2006), 211–223. https://doi.org/10.1016/j.jmaa.2005.05.052 Google Scholar

[22] N. V. Dung and V. Hang, The generalized hyperstability of general linear equations in quasi-Banach spaces, J. Math. Anal. Appl. 462 (1) (2018), 131–147. https://doi.org/10.1016/j.jmaa.2018.01.070 Google Scholar

[23] N. J. Kalton, Curves with zero derivative in F-spaces, Glasg. Math. J. 22 (1) (1981), 19–29. https://doi.org/10.1017/S0017089500004432 Google Scholar

[24] N. J. Kalton, N. T. Peck, and J. W. Roberts, An F-Space Sampler, London Math. Soc. Lecture Note Ser., Vol. 89, Cambridge Univ. Press, Cambridge (1984). https://doi.org/10.1017/CBO9780511662447 Google Scholar

[25] P. W. Cholewa, Remarks on the stability of functional equations, Aequationes Math. 27 (1-2) (1984), 76–86. https://doi.org/10.1007/BF02192660 Google Scholar

[26] Q. Liu, S. Zhuang, and Y. Li, Additive double P-functional inequalities in β-homogeneous F-spaces, J. Math. Inequal. 15 (2) (2021), 605–613. https://doi.org/10.7153/jmi-2021-15-44 Google Scholar

[27] Q. Liu, S. Zhuang, and Y. Li, On the stability of orthogonal additivity in β-homogeneous F-spaces, J. Math. Res. Appl. 42 (3) (2022), 289–296. https://doi.org/10.3770/j.issn:2095-2651.2022.03.007 Google Scholar

[28] R. Ger and J. Sikorska, Stability of the orthogonal additivity, Bull. Polish Acad. Sci. Math. 43 (2) (1995), 143–151. Google Scholar

[29] S. Czerwik, On the stability of the quadratic mapping in normed spaces, Abh. Math. Semin. Univ. Hambg. 62 (1992), 59–64. https://doi.org/10.1007/BF02941618 Google Scholar

[30] S. Czerwik, Functional Equations and Inequalities in Several Variables, World Scientific, Singapore (2002). https://doi.org/10.1142/4875 Google Scholar

[31] S. Czerwik, Stability of Functional Equations of Ulam-Hyers-Rassias Type, Hadronic Press, Palm Harbor, FL (2003). Google Scholar

[32] S. M. Ulam, Problems in Modern Mathematics, Interscience Publ., New York (1960). Google Scholar

[33] S. M. Ulam, A Collection of Mathematical Problems, Interscience Publ., New York (1960). https://doi.org/10.1126/science.132.3428.665 Google Scholar

[34] T. M. Rassias, On the stability of the linear mapping in Banach spaces, Proc. Amer. Math. Soc. 72 (2) (1978), 297–300. https://doi.org/10.2307/2042795 Google Scholar

[35] T. M. Rassias, On the stability of functional equations in Banach spaces, J. Math. Anal. Appl. 251 (1) (2000), 264–284. https://doi.org/10.1006/jmaa.2000.7046 Google Scholar

[36] T. M. Rassias, Functional Equations, Inequalities and Applications, Kluwer Acad. Publ., Dordrecht (2003). https://doi.org/10.1007/978-94-017-0225-6 Google Scholar

[37] W. Fechner and J. Sikorska, On the stability of orthogonal additivity, Bull. Pol. Acad. Sci. Math. 58 (1) (2010), 23–30. https://doi.org/10.4064/ba58-1-3 Google Scholar