Enriques surface

In mathematics, an Enriques surface is an algebraic surface such that the irregularity q = 0 and the canonical line bundle is non-trivial but has trivial square. Enriques surfaces are all algebraic (and therefore Kähler) and are elliptic surfaces of genus 1. They are quotients of K3 surfaces by a group of order 2 acting without fixed points and their theory is similar to that of algebraic K3 surfaces.
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