It is generally conjectured that the Mann iteration converges faster than the Ishikawa iteration for any operator defined on an arbitrary closed convex subset of a Banach space. The recent result of Babu et al [1] shows that this conjecture can be proved for a class of quasi-contractive operators called the Zamfirescu operators[10]. In this paper it is shown that the proof can indeed be general...

We prove the existence of fixed points of monotone quasi-contraction mappings in metric and modular metric spaces. This is the extension of Ran and Reurings fixed point theorem for monotone contraction mappings in partially ordered metric spaces to the case of quasicontraction mappings introduced by Ćirić. The proofs are based on Lemmas ?? and ??, which contain two crucial inequalities essentia...

In this paper direct proofs of some common fixed point results for two and three mappings under weak contractive conditions are given. Some of these results are improved by using different arguments of control functions. Examples are presented showing that some generalizations cannot be obtained and also that our results are distinct from the existing ones.

In this work, we give a partial positive answer to the question concerning set-valued quasicontraction proposed by Amini-Harandi (Appl. Math. Lett. 24:1791-1794 2011). By useful lemma, prove fixed point theorem for quasi-contraction, which extends range of contraction constant in result from [0, 1/2) 1/3? 3). Also, new simple proof quasi-contraction type Haghi et al. 25:843-846 2012). Finally, ...

As a generalization to Banach contraction principle, ´ Ciri´c introduced the concept of quasi-contraction mappings. In this paper, we investigate these kinds of mappings in modular function spaces without the Δ 2-condition. In particular, we prove the existence of fixed points and discuss their uniqueness.

Motivated by structured parasite populations in aquaculture we consider a class of size-structured population models, where individuals may be recruited into the population with distributed states at birth. The mathematical model which describes the evolution of such a population is a first-order nonlinear partial integro-differential equation of hyperbolic type. First, we use positive perturba...

given a mapping $f:xto x$ we naturally associate to it a monotonic map $gg_f:exp xto exp x$ from the power set of $x$ into itself, thus inducing a generalized topology on $x$. in this paper we investigate some properties of generalized topologies which are defined by such a procedure.