4 papers
A generalization of tight closure and multiplier ideals
Nobuo Hara, Ken-ichi Yoshida
We introduce a new variant of tight closure associated to any fixed ideal $\a$, which we call $\a$-tight closure, and study various properties thereof. In our theory, the annihilat…
On a generalization of test ideals
Nobuo Hara, Shunsuke Takagi
The test ideal of a ring of prime characteristic is an important object in the theory of tight closure. In this paper, we study a generalization of the test ideal, which…
F-regular and F-pure rings vs. log terminal and log canonical singularities
Nobuo Hara, Kei-ichi Watanabe
In this paper, we investigate the relationship of F-regular (resp. F-pure) rings and log terminal (resp. log canonical) singularities. Also, we extend the notions of F-regularity a…
On the cone of curves of an abelian variety
Thomas Bauer
Let be a smooth projective variety over the complex numbers. One knows by the Cone Theorem that the closed cone of curves of is rational polyhedral whenever is amp…