Unirationality of del Pezzo surfaces of degree two over finite fields (extended version)

Abstract

We prove that every del Pezzo surface of degree two over a finite field is unirational, building on the work of Manin and an extension by Salgado, Testa, and Várilly-Alvarado, who had proved this for all but three surfaces. Over general fields, we state several sufficient conditions for a del Pezzo surface of degree two to be unirational.

Some minor changes, including the title. We have posted a shorter version with the original title and we have called this the extended version. 21 pages; a file with magma code verifying some computational claims can be obtained by downloading the source