2021-12-07T06:54:51Zhttps://repository.dl.itc.u-tokyo.ac.jp/oaioai:repository.dl.itc.u-tokyo.ac.jp:000402862021-03-01T21:02:55ZRemarks on Gorenstein Terminal Fourfold FlipsTakagi, Hiromichi138883415flipextremal rayapplication/pdfWe prove that for any flipping contraction from a Gorenstein terminal $4$-fold, a general hyperplane section which contains the exceptional locus has only canonical singularities. Based on this fact and using Ran's theorem, we prove the existence of the flip of a flipping contraction from a Gorenstein terminal $4$-fold whose general hyperplane section has only isolated canonical singularities and exceptional locus is irreducible. Furthermore we classify such flipping contractions and flips.departmental bulletin paperGraduate School of Mathematical Sciences, The University of Tokyo1998application/pdfJournal of mathematical sciences, the University of Tokyo15149164AA1102165313405705https://repository.dl.itc.u-tokyo.ac.jp/record/40286/files/jms050107.pdfeng