Abstract
We generalize the notions of F-regular and F-pure rings to pairs \((R,\mathfrak{a}^t)\) of rings R and ideals \(\mathfrak{a} \subset{R}\) with real exponent t>0, 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 a sort of Inversion of Adjunction of arbitrary codimension, which states that for a pair (X,Y) of a smooth variety X and a closed subscheme \(Y\subsetneq{X}\), if the restriction (Z,Y| Z ) to a normal ℚ-Gorenstein closed subvariety \(Z\subsetneq{X}\) is klt (resp. lc), then the pair (X,Y+Z) is plt (resp. lc) near Z.
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References
Aberbach, I., MacCrimmon, B.: Some results on test elements. Proc. Edinb. Math. Soc., II. Ser. 42, 541–549 (1999)
Ambro, F.: Inversion of Adjunction for non-degenerate hypersurfaces. Manuscr. Math. 111, 43–49 (2003)
Ein, L., Mustaţa, M.: Inversion of Adjunction for locally complete intersection varieties. arXiv:math.AG/0301164. To appear in Am. J. Math.
Ein, L., Mustaţa, M., Yasuda, T.: Jet schemes, log discrepancies and Inversion of Adjunction. Invent. Math. 153, 519–535 (2003)
Fedder, R.: F-purity and rational singularity. Trans. Am. Math. Soc. 278, 461–480 (1983)
Glassbrenner, D.: Strong F-regularity in images of regular rings. Proc. Am. Math. Soc. 124, 345–353 (1996)
Hara, N.: A characterization of rational singularities in terms of injectivity of Frobenius maps. Am. J. Math. 120, 981–996 (1998)
Hara, N.: Geometric interpretation of tight closure and test ideals. Trans. Am. Math. Soc. 353, 1885–1906 (2001)
Hara, N., Takagi, S.: On a generalization of test ideals. arXiv: math.AC/0210131. To appear in Nagoya Math. J.
Hara, N., Watanabe, K.-i.: F-regular and F-pure rings vs. log terminal and log canonical singularities. J. Algebr. Geom. 11, 363–392 (2002)
Hara, N., Watanabe, K.-i., Yoshida, K.: Rees algebras of F-regular type. J. Algebra 247, 191–218 (2002)
Hara, N., Yoshida, Y.: A generalization of tight closure and multiplier ideals. Trans. Am. Math. Soc. 355, 3143–3174 (2003)
Hironaka, H.: Resolution of singularities of an algebraic variety over a field of characteristic zero. I, II. Ann. Math. (2) 79, 109–203 (1964); ibid. (2) 79, 205–326 (1964)
Hochster, M., Huneke, C.: Tight closure, invariant theory and the Briançon-Skoda theorem. J. Am. Math. Soc. 3, 31–116 (1990)
Hochster, M., Huneke, C.: Tight closure and strong F-regularity. Colloque en l’honneur de Pierre Samuel (Orsay, 1987). Mém. Soc. Math. Fr., Nouv. Sér. 38, 119–133 (1989)
Hochster, M., Roberts, J.: The purity of the Frobenius and local cohomology. Adv. Math. 21, 117–172 (1976)
Kollár, J.: Singularities of pairs. Algebraic geometry—Santa Cruz 1995, 221–287. Proc. Symp. Pure Math. 62, Part 1. Providence, RI: Amer. Math. Soc. 1997
Kollár, J. (with 14 coauthors): Flips and abundance for algebraic threefolds. Astérisque 211 (1992)
Kunz, E.: Characterizations of regular local rings of characteristic p. Am. J. Math. 91, 772–784 (1969)
Lazarsfeld, R.: Positivity in Algebraic Geometry. In preparation
Mehta, V.B., Srinivas. V.: A characterization of rational singularities. Asian J. Math. 1, 249–271 (1997)
Nakayama, N.: Zariski-decomposition and abundance. RIMS preprint series 1142 (1997)
Shokurov, V.V.: 3-fold log flips. Izv. Ross. Akad. Nauk, Ser. Mat. 56, 105–203 (1992)
Smith, K.E.: F-rational rings have rational singularities. Am. J. Math. 119, 159–180 (1997)
Smith, K.E.: The multiplier ideal is a universal test ideal. Commun. Algebra 28, 5915–5929 (2000)
Smith, K.E.: Globally F-regular varieties: applications to vanishing theorems for quotients of Fano varieties. Mich. Math. J. 48, 553–572 (2000)
Takagi, S.: An interpretation of multiplier ideals via tight closure. J. Algebr. Geom. 13, 393–415 (2004)
Takagi, S., Watanabe, K.-i.: On F-pure thresholds. arXiv: math.AC/0312486. Submitted
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Takagi, S. F-singularities of pairs and Inversion of Adjunction of arbitrary codimension. Invent. math. 157, 123–146 (2004). https://doi.org/10.1007/s00222-003-0350-3
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DOI: https://doi.org/10.1007/s00222-003-0350-3