On linear systems of reducible and irreducible quadrics with Jacobian identical zero (Q1074671)

Continuing a series of articles on linear systems of quadrics, the author classifies irreducible systems in \(P^5\) with Jacobian identical zero of characteristic 5. The base of such system is one of the following three types of surfaces: (a) the ruled normal rational surface with two conics in skew planes as directrices; (b) the ruled normal rational surface with directrices a twisted cubic in \(P^3\) and a line skew to \(P^3\); (c) the rational normal cone of degree four.