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

Rikito Ohta; Shinnosuke Okawa

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arXiv · 1803.03819

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

Rikito Ohta·Shinnosuke Okawa

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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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BibTeX RIS

Rikito Ohta, Shinnosuke Okawa. 2020-09-15. On ruled surfaces with big anti-canonical divisor and numerically trivial divisors on weak log Fano surfaces. https://arxiv.org/abs/1803.03819

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