Semipolarized nonruled surfaces with sectional genus two.
Smooth quartic surfaces with 352 conics.
Special divisors on curves on a K3 surface.
Special Kähler metrics on complex line bundles and the geometry of -surfaces.
Special rank two vector bundles over Enriques surfaces.
String theory and duality.
Supersingular K 3 surfaces with big Artin invariant.
Surfaces d'Enriques et une construction de surfaces de type général avec pg = 0.
Symplectic involutions on deformations of K3[2]
Let X be a hyperkähler manifold deformation equivalent to the Hilbert square of a K3 surface and let φ be an involution preserving the symplectic form. We prove that the fixed locus of φ consists of 28 isolated points and one K3 surface, and moreover that the anti-invariant lattice of the induced involution on H 2(X, ℤ) is isomorphic to E 8(−2). Finally we show that any couple consisting of one such manifold and a symplectic involution on it can be deformed into a couple consisting of the Hilbert...