Base curves of multicanonical systems on threefolds
Beispiele dreidimensionaler Hilbertscher Modulmannigfaltigkeiten von allgemeinem Typ.
Boundedness for threefolds in P6 containing a smooth ruled surface as hyperplane section.
Let X ⊂ P6 be a smooth irreducible projective threefold, and d its degree. In this paper we prove that there exists a constant β such that for all X containing a smooth ruled surface as hyperplane section and not contained in a fourfold of degree less than or equal to 15, d ≤ β. Under some more restrictive hypothesis we prove an analogous result for threefolds containing a smooth ruled surface as hyperplane section and contained in a fourfold of degree less than or equal to 15.