Journal of Topology Advance Access originally published online on September 17, 2009
Journal of Topology 2009 2(3):517-526; doi:10.1112/jtopol/jtp021
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© 2009 London Mathematical Society
On maximal poles of zeta functions, roots of b-functions, and monodromy Jordan blocks
Facultad de Matemáticas, Universidad Complutense, Plaza de Ciencias 3, E-28040, Madrid, Spain amelle@mat.ucm.es
Laboratoire Jean Alexandre Dieudonné, Université de Nice-Sophia Antipolis, Faculté des Sciences, Parc Valrose, 06108 Nice Cedex 02, France tristan.torrelli@laposte.net
University of Leuven, Department of Mathematics, Celestijnenlaan 200B, B-3001 Leuven (Heverlee), Belgium wim.veys@wis.kuleuven.be
| Abstract |
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The main objects of this study are the poles of several local zeta functions: the Igusa, topological, and motivic zeta function associated to a polynomial or (germ of) holomorphic function in n variables. We are interested in poles of maximal possible order n. In all known cases (curves, non-degenerate polynomials) there is at most one pole of maximal order n, which is then given by the log canonical threshold of the function at the corresponding singular point. For an isolated singular point we prove that if the log canonical threshold yields a pole of order n of the corresponding (local) zeta function, then it induces a root of the Bernstein–Sato polynomial of the given function of multiplicity n (proving one of the cases of the strongest form of a conjecture of Igusa–Denef–Loeser). For an arbitrary singular point, we show under the same assumption that the monodromy eigenvalue induced by the pole has a Jordan block of size n on the (perverse) complex of nearby cycles.
Received February 25, 2009.
2000 Mathematics Subject Classification Primary: 14B05, 32S25. Secondary: 11S80, 32S45
The first author is partially supported by Spanish Contract MTM2007-67908-C02-02. The third author is partially supported by the Fund of Scientific Research–Flanders (G.0318.06).
Dedicated with admiration to C. T. C. Wall on the occasion of his seventieth birthday