Terminal 3-fold Divisorial Contractions of a Surface to a Curve I
نویسنده
چکیده
Let Γ ⊂ X be a smooth curve on a 3-fold which has only index 1 terminal singularities along this curve. In this paper we investigate the existence of extremal terminal divisorial contractions E ⊂ Y −→ Γ ⊂ X , contracting an irreducible surface E to Γ. We consider cases with respect to the singularities of the general hypersurface section S of X through Γ. We completely classify the cases when S is Ai, i ≤ 3, and D2n for any n.
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