Krasnosel'skiĭ-Schaefer type method in the existence problems
We consider a general integral equation satisfying algebraic conditions in a Banach space. Using Krasnosel'skii-Schaefer type method and technical assumptions, we prove an existence theorem producing a periodic solution of some nonlinear integral equation.
The Sehgal’s Fixed Point Result in the Framework of ρ-Space
In this paper, we prove a fixed point theorem of Sehgal type (see Sehgal, V.M., Proc Amer Math Soc 23: 631–634, 1969) in a more general setting of ρ-space (see Secelean, N.A. and Wardowski, D., Results Math, 72: 919–935, 2017). In this way, we can find, as particular cases, some results of Sehgal type in metric, b-metric and rectangular b-metric spaces.
A General Approach on Picard Operators
In the chapter there are presented the recent investigations concerning the existence and the uniqueness of fixed points for the mappings in the setting of spaces which are not metric with different functions of measuring the distance and in consequence with the various convergence concepts. In this way we obtain the systematized knowledge of fixed point tools which are, in some situations, more convenient to apply than the known theorems with an underlying usual metric space. The appropriate illustrative examples are also presented.
Asymptotics for third-order nonlinear differential equations: Non-oscillatory and oscillatory cases
We discuss a third-order differential equation, involving a general form of nonlinearity. We obtain results describing how suitable coefficient functions determine the asymptotic and (non-)oscillatory behavior of solutions. We use comparison technique with first-order differential equations together with the Kusano–Naito’s and Philos’ approaches.