5 On surfaces with p g = q = 1 and non - ruled bicanonical involution
نویسنده
چکیده
We classify surfaces of general type S with pg = q = 1 having an involution i such that S/i is non-ruled and the bicanonical map of S factors through the natural cover S → S/i. We prove that the minimal model of S/i is either a K3 surface or a surface of Kodaira dimension 1 (in this last case S has a genus 2 fibration). We also show that these cases do occur. In particular we construct a surface of general type with pg = q = 1 and K 2 = 6. 2000 Mathematics Classification: 14J29.
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