Geometric object

Complex projective K3 surface

Complex dimension 2.

Hodge diamond

The entries are hp,q = dimℂ Hq(X, ΩpX). Row k has p + q = k, with p increasing from left to right.

1
00
1201
00
1

Symmetry group: D4.

Numerical invariants

Euler characteristic: 24.

Dimension of the local deformation space: 20.

Betti numbers: b0 = 1, b1 = 0, b2 = 22, b3 = 0, b4 = 1.

Chern numbers

  • ∫c2 = 24

Cohomology lattices

  • H2(X; ℤ)/tors, with the cup-product intersection form: U^3 + E8(-1)^2.

Notes

The Hodge series and the intersection lattice are constant for complex K3 surfaces (Huybrechts 2016). The listed local deformation dimension concerns complex K3 surfaces; the projective locus has dimension 19 within each polarized family (Huybrechts 2016).

Huybrechts, Daniel. 2016. Lectures on K3 Surfaces. Cambridge University Press. https://doi.org/10.1017/CBO9781316594193.