English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Zendy Pro

Presents the zaia usage as premium feature

ZAIA

Presents AI Discovery search usage as a premium feature

AI Discovery

Presents AI Discovery explain and summary usage as a premium feature

Content Analysis

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Presents the pdf analysis as premium feature

PDF Analysis

1500 Top-up

3000 Top-up

Zendy Basic

2500 Top-up

Zendy Unlimited

Presents the access of premium content as premium feature

Premium Content

We consider the class of singular double coverings $X \to \PP^3$ ramified inthe degeneration locus $D$ of a family of 2-dimensional quadrics. These areprecisely the quartic double solids constructed by Artin and Mumford asexamples of unirational but nonrational conic bundles. With such quarticsurface $D$ one can associate an Enriques surface $S$ which is the factor ofthe blowup of $D$ by a natural involution acting without fixed points (suchEnriques surfaces are known as nodal Enriques surfaces or Reye congruences). Weshow that the nontrivial part of the derived category of coherent sheaves onthis Enriques surface $S$ is equivalent to the nontrivial part of the derivedcategory of a minimal resolution of singularities of $X$.

On nodal Enriques surfaces and quartic double solids