K3 örgüsünün ters-değişmez altörgüsündeki yörüngeler

AbstractWhen a K3-surface doubly-covers an Enriques surface, the coveringtransformation induces an involution on the second cohomology groupof the K3 surface which is a lattice under the cup-product. The anti-invariant classes form a sublattice of this K3 lattice. In this thesis, wewill determine the number of orbits of primitive cohomology classes inthis sublattice under the action of its self-isometries. We will also derivesome conclusions on certain divisors of the moduli space of Enriquessurfaces. Also a short survey on finiteness results of linear system ofcurves on K3 and Enriques surfaces is given.1