Skip to main content
3 of 3
edited body
Nick L
  • 7k
  • 1
  • 15
  • 41

Leech lattice and rational varieties

Question: Is there a smooth rational variety $X$ of complex dimension $4n$, $n \in \mathbb{N}$; such that the intersection form on $H^{4n}(X,\mathbb{Z})$ is the Leech lattice?

My motivation is mainly curiosity combined with the fact that the other well-known symmetric, positive definite forms appear in this way, i.e. the well-known lattices $\Gamma_{4k}$ (of which $\Gamma_{8}$ is the famous $E_{8}$ lattice) appear as the intersection bilinear form of an complete intersection of two quadrics in $\mathbb{CP}^{4k-2}$. Due to work of Libgober and Wood (On the topological structure of even dimensional complete intersections, Trans.Amer.Math.Soc. 267 (1981) 637-660) the Leech lattice does not appear as the intersection form of any smooth complete intersection.

If such an example is not known I would also be curious to know if it is true without the rationality assumption or if there is an example containing the Leech lattice as a unimodular summand of the intersection form, etc.

Nick L
  • 7k
  • 1
  • 15
  • 41