On the Internal Nuclei of Sets in PG(n,q), q is Odd

In PG(2,q) it is well known that if k is close to q, then any k-arc is contained in a conic. The internal nuclei of a point set form an arc. In this article it is proved that for q odd the above bound on the number of points could be lowered to (or even less), if the arc is obtained as the set of internal nuclei of some point set of proper size. Using this result the internal nuclei of point sets of size q + 1 will be studied in higher dimensional spaces, and an application will be presented to so-called threshold schemes.