Sur la dérivabilité des fonctions à variation bornée
For a given function in some classes related to real derivatives, we examine the structure of the set of points which are not Lebesgue points. In particular, we prove that for a summable approximately continuous function, the non-Lebesgue set is a nowhere dense nullset of at most Borel class 4.
We present a method of integration along the lines of the Henstock-Kurzweil integral. All -derivatives are integrable in this method.
A function is said to have the -th Laplace derivative on the right at if is continuous in a right neighborhood of and there exist real numbers such that converges as for some . There is a corresponding definition on the left. The function is said to have the -th Laplace derivative at when these two are equal, the common value is denoted by . In this work we establish the basic properties of this new derivative and show that, by an example, it is more general than the generalized...