Conic bundles that are not birational to numerical Calabi--Yau pairs

Let $X$ be a general conic bundle over the projective plane with branch curve of degree at least 19. We prove that there is no normal projective variety $Y$ that is birational to $X$ and such that some multiple of its anticanonical divisor is effective. We also give such examples for 2-dimensional c...

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Bibliographic Details
Main Author: János Kollár
Format: Article
Language:English
Published: Association Epiga 2017-09-01
Series:Épijournal de Géométrie Algébrique
Subjects:
Online Access:https://epiga.episciences.org/1518/pdf