Algebraic geometry online seminars on K3 surfaces

[Alessandro Nobile]

Dear all,
    this is to announce the seventeenth algebraic geometry seminar on K3
surfaces.

SPEAKER: Vitantonio Peragine 

WHEN: Friday, July 17 at 4.00 pm (Rome)

WHERE: Link Zoom:  
https://sissa-it.zoom.us/j/91298666403?pwd=WG9wb3VLT0lsalVDTFBjZjNMVEFRdz09
       Meeting ID:  912 9866 6403 
       Password:    655389

TITLE: An introduction to Enriques surfaces

ABSTRACT: Enriques surfaces constitute one of the four classes of
surfaces of Kodaira dimension zero. In this talk we will review some
properties of Enriques surfaces (in any characteristic). We start by
showing that Enriques surfaces can be divided in two classes (called
classical and non-classical), according to their canonical line bundle;
non-classical Enriques surfaces (which exist only in characteristic 2)
can be further divided in two classes (ordinary and super-singular),
according to the structure of their Picard scheme. We then show that the
Picard lattice of an Enriques surface is a unimodular hyperbolic lattice
of rank 10, and that every Enriques surface admits a principal double
cover by a "K3-like" surface, whose non-singular model is either a K3
surface or a rational surface. We conclude with an example of classical
and non-classical Enriques surfaces in characteristic 2. 

Everyone interested is welcomed to attend.

Best regards,
Alessandro