Disegni di sistemi di Steiner ed iperovali non regolari PG(2,q)
Received: October 20, 1997
Classificazione AMS 51E21
Starting from a Stainer system S(2,k,v), we construct some designs and study the two characters sets in such designs. Moreover, we get an expression for the number of non-regular hyperovals of PG(2,q).