Resumen de Characterization of curves in ?(2)

Meritxell Sáez Cornellana

• In this paper we characterize the irreducible curves lying in ?(2) . We prove that a curve B has a degree one morphism to ?(2) with image a curve of degree d, with irreducible preimage in ?×? , if and only if there exists an irreducible smooth curve D and morphisms from D to C and B, of degrees d and 2 respectively, forming a diagram which does not reduce.