Rational curves and Seshadri constants on Enriques surfaces (2212.08191v2)

Abstract: We prove that classes of rational curves on very general Enriques surfaces are always $2$-divisible. As a consequence, we prove that the Seshadri constant of any big and nef line bundle on a very general Enriques surface coincides with the value of the $\phi$-function introduced by Cossec.