A generalization of the Lebesgue density theorem via modulus density
Abstract
In this paper, we introduce the notion of a -density point for Lebesgue-measurable subsets of , where is a modulus function, and study its basic measure-theoretic properties. We show that every -density point is a Lebesgue density point, while under Condition~(A) the two notions coincide. Consequently, for such modulus functions, the set of -density points of a measurable set differs from the set itself only by a null set, yielding a modulus version of the Lebesgue Density Theorem. We then define the associated -density topology and investigate its structure. In general, is contained in the classical Lebesgue density topology, and if satisfies Condition~(A), then . We also compare with -density topologies and establish several topological properties of , including that countable sets are -closed and that is nonseparable, nonregular, and nonmetrizable. Finally, we introduce -approximately continuous functions, prove that they form a vector space, and show that the bounded class of such functions is a Banach space under the supremum norm.
Cite
@article{arxiv.2604.13626,
title = {A generalization of the Lebesgue density theorem via modulus density},
author = {H. S. Behmanush and M. Küçükaslan},
journal= {arXiv preprint arXiv:2604.13626},
year = {2026}
}