A characterization of the primals in \(PG(m,2)\)
Let \(X\) be a set of the projective space \(PG(m,2)\) over the field with two elements, and let \(0\leq r\leq m\). The author proves that \(X\) is a primal of degree \(r\) (i.e. defined by a form of degree \(r\)) if and only if \(X\) intersects every \(r\)-flat in an odd number of points.
scientific article; zbMATH DE number 95041