Function spaces and fixed point properties: a Galois connection.
Functional compression-expansion fixed point theorem.
Functionally Countable Spaces and Baire Functions
The concept of the distinguished sets is applied to the investigation of the functionally countable spaces. It is proved that every Baire function on a functionally countable space has a countable image. This is a positive answer to a question of R. Levy and W. D. Rice.
Functions Equivalent to Borel Measurable Ones
Let X and Y be two Polish spaces. Functions f,g: X → Y are called equivalent if there exists a bijection φ from X onto itself such that g∘φ = f. Using a theorem of J. Saint Raymond we characterize functions equivalent to Borel measurable ones. This characterization answers a question asked by M. Morayne and C. Ryll-Nardzewski.
Furi–Pera fixed point theorems in Banach algebras with applications
In this work, we establish new Furi–Pera type fixed point theorems for the sum and the product of abstract nonlinear operators in Banach algebras; one of the operators is completely continuous and the other one is -Lipchitzian. The Kuratowski measure of noncompactness is used together with recent fixed point principles. Applications to solving nonlinear functional integral equations are given. Our results complement and improve recent ones in [10], [11], [17].
Furstenberg families and sensitivity.
Furstenberg’s theorem in topological dynamics
Further properties of an extremal set of uniqueness
Fuzzy distances
In the paper, three different ways of constructing distances between vaguely described objects are shown: a generalization of the classic distance between subsets of a metric space, distance between membership functions of fuzzy sets and a fuzzy metric introduced by generalizing a metric space to fuzzy-metric one. Fuzzy metric spaces defined by Zadeh’s extension principle, particularly to are dealt with in detail.
Fuzzy filter spectrum of a BCK algebra.
Fuzzy neighborhood structures on partially ordered groups.
Fuzzy stability of the pexiderized quadratic functional equation: A fixed point approach.