On ruled surfaces with big anti-canonical divisor and numerically trivial divisors on weak log Fano surfaces

2018/03/10 by Ohta, Rikito, Okawa, Shinnosuke
#Algebraic Geometry (math.AG) #FOS: Mathematics

paper · doi:10.48550/arxiv.1803.03819

Abstract

We investigate the structure of geometrically ruled surfaces whose anti-canonical class is big. As an application we show that the Picard group of a normal projective surface whose anti-canonical class is nef and big is a free abelian group of finite rank.

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