| Dedicated to the memory of Professor Mihail Megan
Adrian Petrușel†, Gabriela Petrușel‡, Jen-Chih Yao§ Abstract: In the framework of a complete b-metric space, we will discuss existence and uniqueness results for the fixed points of triangular operators. Using various classical metric conditions on the operators, we will obtain a generalization of the well-known fibre contraction principle in complete metric spaces. Keywords: fixed point, complete b-metric space, contraction, Picard operator, Ulam-Hyers stability, well-posedness in the sense of Reich-Zaslavski. MSC: 47H10, 54H25. DOI 10.56082/annalsarscimath.2026.3.47 Read full article *Accepted for publication on March 10, 2026 |
PUBLISHED in Annals Academy of Romanian Scientists Series on Mathematics and Its Application, ISSN ONLINE 2066 – 6594 |

