Quartic threefolds containing two skew double lines
Quasi-Gorenstein Fano 3-folds with isolated non-rational loci
Quasi-lines and their degenerations
In this paper we study the structure of manifolds that contain a quasi-line and give some evidence towards the fact that the irreducible components of degenerations of the quasi-line should determine the Mori cone. We show that the minimality with respect to a quasi-line yields strong restrictions on fibre space structures of the manifold.