paper

F-singularities of pairs and Inversion of Adjunction of arbitrary codimension

arXiv:math/0305286 · doi:10.1007/s00222-003-0350-3

Abstract

We generalize the notions of F-regular and F-pure rings to pairs $(R,\a^t)$ of rings and ideals $\a \subset R$ with real exponent , and investigate these properties. These ``F-singularities of pairs'' correspond to singularities of pairs of arbitrary codimension in birational geometry. Via this correspondence, we prove Inversion of Adjunction of arbitrary codimension, which states that for a pair of a smooth variety and a closed subscheme , if the restriction to a normal $\Q$-Gorenstein closed subvariety is klt (resp. lc), then the pair is plt (resp. lc) near .

21 pages, AMS-LaTeX; v.2: minor changes, to appear in Invent. Math

References in corpus (1)

Cited by in corpus (27)