Projective Surfaces with a three-divisible Set of Cusps
نویسنده
چکیده
0 Introduction We consider algebraic surfaces Y ⊂ IP3(C). A cusp (=singularity A2) on Y is a singularity near which the surface is given in local (analytic) coordinates x, y and z, centered at the singularity, by an equation xy − z = 0. This is an isolated quotient singularity C2/ZZ3. A set P1, ..., Pn of cusps on Y is called 3-divisible, if there is a cyclic global triple cover of Y branched precisely over these cusps. Equivalently: If π : X → Y is the minimal desingularization introducing two (−2)-curves E ν , E ′′ ν over each cusp, there is a way to label these curves such that the divisor class of
منابع مشابه
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