We introduce the concept of triangular αc-admissible mappings (pair of mappings) with respect to ηc nonself-mappings and establish the existence of PPF dependent fixed (coincidence) point theorems for contraction mappings involving triangular αc-admissible mappings (pair of mappings) with respect to ηc nonself-mappings in Razumikhin class. Several interesting consequences of our theorems are al...

The setting of this article is Bishop’s constructive mathematics. The connections between the strong mappings, U -mappings and L-mappings of co-quasiorder relational systems we analyzed. The relations between the strong mappings of co-quasiorder relational systems defined by Novotny and other mappings are also analysed. Finally, a new mapping between two relational systems is introduced. Some p...

In the present paper, we show that $S^*$ iteration method can be used to approximate fixed point of almost contraction mappings. Furthermore, we prove that this iteration method is equivalent to CR iteration method  and it produces a slow convergence rate compared to the CR iteration method for the class of almost contraction mappings. We also present table and graphic to support this result. F...