Multiplicities and log canonical threshold
Authors:
Tommaso de Fernex, Lawrence Ein and Mircea Mustaţǎ
Journal:
J. Algebraic Geom. 13 (2004), 603615
DOI:
https://doi.org/10.1090/S1056391104003467
Published electronically:
February 25, 2004
MathSciNet review:
2047683
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Abstract  References  Additional Information
Abstract: Given an $n$dimensional local ring $R$ of a smooth variety, and a zerodimensional ideal $I\subset R$, we prove the following inequality involving the Samuel multiplicity and the log canonical threshold: $e(I)\geq n^n/\operatorname {lc}(I)^n$. Moreover, equality holds if and only if the integral closure of $I$ is a power of the maximal ideal in $R$. When $n=2$, we give a similar inequality for an arbitrary ideal $I$.

[Co]corti A. Corti, Singularities of linear systems and $3$fold birational geometry, in Explicit birational geometry of $3$folds, 259–312, Cambridge Univ. Press, Cambridge, 2000.
[CPR]CPR A. Corti, A.V. Pukhlikov and M. Reid, Fano $3$fold hypersurfaces, in Explicit birational geometry of $3$folds, 175–258, Cambridge Univ. Press, Cambridge, 2000.
[DEM]DEM T. de Fernex, L. Ein and M. Mustaţǎ, Bounds for log canonical thresholds with applications to birational rigidity, Math. Res. Lett. 10 (2003), 219–236.
[DK]DK J.P. Demailly and J. Kollár, Semicontinuity of complex singularity exponents and KählerEinstein metrics on Fano orbifolds, Ann. Sci. École Norm. Sup. (4) 34 (2001), 525–556.
[Ei]eisenbud D. Eisenbud, Commutative algebra with a view toward algebraic geometry, Grad. Texts in Math. 150, Springer, New York, 1995.
[GG]GG T. Gaffney and R. Gassler, Segre numbers and hypersurface singularities, J. Algebraic Geom. 8 (1999), 695–736.
[Ho]howald J. Howald, Multiplier ideals of monomial ideals, Trans. Amer. Math. Soc. 353 (2001), 2665–2671.
[IM]IM V.A. Iskovskikh and Yu. I. Manin, Threedimensional quartics and counterexamples to the Lüroth problem, Math. USSR Sbornik 15 (1971), 141–166.
[Ko]kollar J. Kollár, Singularities of pairs, in Algebraic Geometry—Santa Cruz 1995, 221–287, Proc. Sympos. Pure Math., 62, Amer. Math. Soc., Providence, RI, 1997.
[Mu]mustata M. Mustaţǎ, Singularities of pairs via jet schemes, J. Amer. Math. Soc. 15 (2002), 599–615.
[Pu1]Pu1 A.V. Pukhlikov, Birationally rigid Fano hypersurfaces, preprint 2002, math.AG/ 0201302.
[Pu2]Pu2 A.V. Pukhlikov, Essentials of the method of maximal singularities, in Explicit birational geometry of $3$folds, 73–100, Cambridge Univ. Press, Cambridge, 2000.
[Pu3]Pu3 A.V. Pukhlikov, Birational automorphisms of a fourdimensional quintic, Invent. Math. 87 (1987), 303–329.
[Re]Rees D. Rees, ${\mathfrak a}$transforms of local rings and a theorem on multiplicities of ideals, Proc. Cambridge Philos. Soc. 57 (1961), 8–17.
Additional Information
Tommaso de Fernex
Affiliation:
Department of Mathematics, University of Michigan, 525 East University Avenue, Ann Arbor, Michigan 481091109
MR Author ID:
635850
Email:
defernex@math.uic.edu
Lawrence Ein
Affiliation:
Department of Mathematics, Statistics and Computer Science, University of Illinois at Chicago, 851 Morgan St., M/C. 249, Chicago, Illinois 606077045
MR Author ID:
62255
Email:
ein@math.uic.edu
Mircea Mustaţǎ
Affiliation:
Department of Mathematics, Harvard University, One Oxford Street, Cambridge, Massachusetts 02138
Email:
mirceamustata@yahoo.com
Received by editor(s):
May 23, 2002
Published electronically:
February 25, 2004
Additional Notes:
Research of the first author was partially supported by MURST of Italian Government, National Research Project (Cofin 2000) “Geometry of Algebraic Varieties”. Research of the second author was partially supported by NSF Grant DMS 9970295. The third author served as a Clay Mathematics Institute LongTerm Prize Fellow while this research was done.