Calabi-Yau-threefolds with Picard number ρ(X)=2 and their Kaehler cone I

الأصل · EN

We describe properties of the Kähler cone of general Calabi-Yau-threefolds with Picard number ρ(X)=2 and prove the rationality of the Kähler cone, if X is a Calabi-Yau-hypersurface in a P²-bundle over P² and c₃(X)≤ -54. Without the latter assumption we prove the positivity of c₂(X).