K3 double structures on Enriques surfaces and their smoothings

Francisco Javier Gallego, Miguel Gonzalez, Bangere P. Purnaprajna

Let $Y$ be a smooth Enriques surface. A $K3$ carpet on $Y$ is a locally Cohen-Macaulay double structure on $Y$ with the same invariants as a smooth $K3$ surface (i.e., regular and…