STEFANIA FERRI

**Summary**

We prove that a k-set K of PG(3,q) with k ≤ q^{2} + 1
of class [0, m, n,]_{1} with respect to the lines, such that at the most q+1 m-secant lines meet at each point of K, is a (q^{2}+1)-cap and hence, if q is odd, is an elliptic quadric.

Home Riv.Mat.Univ.Parma