On the product of derivatives
On the quasiarithmetic mean in a mean value property and the associated functional equation.
On the set where an approximate derivative is a derivative
On the symmetry of approximate Dini derivates of arbitrary functions
On the symmetry of Dini derivates of arbitrary functions
On the transformers of derivatives
On the transformers of the Zahorski classes of functions
On the -finiteness of a variational measure
The -finiteness of a variational measure, generated by a real valued function, is proved whenever it is -finite on all Borel sets that are negligible with respect to a -finite variational measure generated by a continuous function.
On topological properties of the spaces of Darboux Baire 1 functions and bounded derivatives
We investigate the topological structure of the space 𝓓ℬ₁ of bounded Darboux Baire 1 functions on [0,1] with the metric of uniform convergence and with the p*-topology. We also investigate some properties of the set Δ of bounded derivatives.
On two mean value properties and functional equations associated with them.
On uniform symmetric derivatives
On Whitney pairs
A simple arc ϕ is said to be a Whitney arc if there exists a non-constant function f such that for every . G. Petruska raised the question whether there exists a simple arc ϕ for which every subarc is a Whitney arc, but for which there is no parametrization satisfying . We answer this question partially, and study the structural properties of possible monotone, strictly monotone and VBG* functions f and associated Whitney arcs.