Published online by Cambridge University Press: 21 July 2021
We prove that there are finitely many families, up to isomorphism in codimension one, of elliptic Calabi–Yau manifolds $Y\rightarrow X$ with a rational section, provided that $\dim (Y)\leq 5$ and $Y$ is not of product type. As a consequence, we obtain that there are finitely many possibilities for the Hodge diamond of such manifolds. The result follows from log birational boundedness of Kawamata log terminal pairs $(X, \Delta )$ with $K_X+\Delta$ numerically trivial and not of product type, in dimension at most four.
G.D.C. is partially supported by the Simons Foundation and NSF grant DMS-1702358. Most of this work was completed during several visits of R.S. to Columbia University. He would like to thank Columbia University for the hospitality and the nice working environment. He would also like to thank MIT where he was a graduate student and UCSD where he was a visitor when part of this work was completed. He kindly acknowledges financial support from NSF research grant nos 1200656 and 1265263 and Churchill College, Cambridge. During the final revision of this work he was supported by funding from the European Research Council under the European Union's Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement no. 307119.