摘要
Let f : X → B be a generic ordinary proper fibration over a complete curve in positive characteristics, we prove that the dual of higher direct image sheaf R^1 f_*O_X is nef. As a corollary, we show that f_*ω_(S/B) is nef, if f : S → B is a fibration from a surface to a curve with generic ordinary fibres.
Let f ： X → B be a generic ordinary proper fibration over a complete curve in positive characteristics, we prove that the dual of higher direct image sheaf R^1 f＊OX is nef. As a corollary, we show that f＊ω（S/B） is nef, if f ： S → B is a fibration from a surface to a curve with generic ordinary fibres.
基金
supported by National Natural Science Foundation of China(Grant Nos.11231003 and 11321101)
关键词
曲线
数学
理论研究
计算方法
semipositivity
fibrations
direct image sheaf
