The Existence of Gorenstein Terminal Fourfold Flips
نویسندگان
چکیده
We prove that for a flipping contraction from a Gorenstein terminal 4fold, the pull back of a general hyperplane section of the down-stair has only canonical singularities. Based on this fact and using Siu-Kawamata-Nakayama’s extension theorem [Si], [Kaw4], [Kaw5] and [Nak2], we prove the existence of the flip of such a flipping contraction. Furthermore we classify such flipping contractions and the flips under some additional assumptions.
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