Intersection conditions for some density and I-density local systems (Q750634)

The notion of the local system has been introduced in the book ``Real functions'' (1985; Zbl 0581.26001) by \textit{B. S. Thomson}. In the same book he has presented several kinds of so-called intersection conditions. Both notions have proved their usefulness in proving new theorems as well as in simplifying and unifying proofs of new facts. The author of the reviewed paper has studied the intersection conditions for several local systems connected with the notion of density (with respect to Lebesgue measure) and with the notion of category analogue of density. In many cases systems under consideration possess even a stronger version of the intersection condition.