1. Multiplicative functions additive on polygonal numbers

   • Byungchan Kim
   • Ji Young Kim
   • Poo-Sung Park

   OriginalPaper 28 June 2021 Pages: 601 - 621

2. Means, Milne’s inequality, and quadrilateral area

   • Claudi Alsina
   • Roger B. Nelsen

   OriginalPaper 15 June 2021 Pages: 623 - 627

   

3. Non-existence of measurable solutions of certain functional equations via probabilistic approaches

   • Kazuki Okamura

   OriginalPaper 26 May 2021 Pages: 629 - 637

4. Quasi-arithmetic-type invariant means on probability space

   • Beata Deręgowska
   • Paweł Pasteczka

   OriginalPaper 01 January 2021 Pages: 639 - 651

5. Volumetric bounds for intersections of congruent balls in Euclidean spaces

   • Károly Bezdek

   OriginalPaper 01 June 2021 Pages: 653 - 665

6. On the hyperstability of the generalized class of Drygas functional equations on semigroups

   • Muaadh Almahalebi
   • Rachid EL Ghali
   • Samir Kabbaj

   OriginalPaper 30 January 2021 Pages: 667 - 676

7. A survey on composition operators on some function spaces

   • Emma D’Aniello
   • Martina Maiuriello

   OriginalPaper Open access 30 December 2020 Pages: 677 - 697

8. One-sided invertibility of discrete operators with bounded coefficients

   • Luis Eduardo Flores-Zapotitla
   • Yuri I. Karlovich

   OriginalPaper 28 January 2021 Pages: 699 - 735

9. The Kac–Bernstein functional equation on Abelian groups

   • Gennadiy Feldman

   OriginalPaper 08 March 2021 Pages: 737 - 750

10. Remarks on partitions into expanders

    • Federico Vigolo

    OriginalPaper 10 February 2021 Pages: 751 - 759

11. A new approach with new solutions to the Matkowski and Wesołowski problem

    • Janusz Morawiec
    • Thomas Zürcher

    OriginalPaper Open access 22 February 2021 Pages: 761 - 776

    

12. The water capacity of geometrically distributed words

    • M. Archibald
    • A. Knopfmacher

    OriginalPaper 05 March 2021 Pages: 777 - 796

    

13. Correction to: One-sided invertibility of discrete operators with bounded coefficients

    • Luis Eduardo Flores-Zapotitla
    • Yuri I. Karlovich

    Correction 07 April 2021 Pages: 797 - 799