Brzdȩk, Janusz; Ciepliński, Krzysztof On a fixed point theorem in 2-Banach spaces and some of its applications. (English) Zbl 1399.39063 Acta Math. Sci., Ser. B, Engl. Ed. 38, No. 2, 377-390 (2018). MSC: 39B82 47H10 PDFBibTeX XMLCite \textit{J. Brzdȩk} and \textit{K. Ciepliński}, Acta Math. Sci., Ser. B, Engl. Ed. 38, No. 2, 377--390 (2018; Zbl 1399.39063) Full Text: DOI
Bahyrycz, Anna; Ciepliński, Krzysztof; Olko, Jolanta On an equation characterizing multi-Cauchy-Jensen mappings and its Hyers-Ulam stability. (English) Zbl 1349.39043 Acta Math. Sci., Ser. B, Engl. Ed. 35, No. 6, 1349-1358 (2015). MSC: 39B82 39B52 PDFBibTeX XMLCite \textit{A. Bahyrycz} et al., Acta Math. Sci., Ser. B, Engl. Ed. 35, No. 6, 1349--1358 (2015; Zbl 1349.39043) Full Text: DOI
Ciepliński, Krzysztof; Surowczyk, Angelika On the Hyers-Ulam stability of an equation characterizing multi-quadratic mappings. (English) Zbl 1340.39038 Acta Math. Sci., Ser. B, Engl. Ed. 35, No. 3, 690-702 (2015). MSC: 39B82 46S10 39B52 PDFBibTeX XMLCite \textit{K. Ciepliński} and \textit{A. Surowczyk}, Acta Math. Sci., Ser. B, Engl. Ed. 35, No. 3, 690--702 (2015; Zbl 1340.39038) Full Text: DOI