The characterisation of the smallest two fold blocking sets in PG(n, 2)

We characterize the smallest minimal blocking sets of Q(2n,q), q an odd prime, in terms of ovoids of Q(4,q) and Q(6,q). The proofs of these results are written for q=3,5,7 since for these values it was known that every ovoid of Q(4,q) is an elliptic ...

Let $$\mathcal S$$ be a Desarguesian ( n --- 1)-spread of a hyperplane ý of PG ( rn , q ). Let and $${\bar B}$$ be, respectively, an ( n --- 2)-dimensional subspace of an element of $$\mathcal S $$ and a minimal blocking set of an (( r --- 1) n + 1)-...

We show that, for small t, the smallest set that blocks the long secants of the union of t pairwise disjoint Baer subplanes in $$\hbox {PG}(2,q^2)$$PG(2,q2) has size $$t(q+1)$$t(q+1) and consists of t Baer sublines, and, for large t, the smallest such ...