Base Point Free Theorems —saturation, B-divisors, and Canonical Bundle Formula—
نویسنده
چکیده
We reformulate the Kawamata-Shokurov base point free theorem by using the notion of b-divisors and saturation of linear systems, which was introduced by Shokurov. Combining the refined Kawamata-Shokurov base point free theorem with Ambro’s canonical bundle formula, we quickly reprove the main theorem of Kawamata’s paper: Pluricanonical systems on minimal algebraic varieties, without using the notion of generalized normal crossing varieties. We also treat some variants of base point free theorems mainly due to Fukuda, and generalize base point free theorems for quasi klt pairs.
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