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$\mu ^*$-ZARISKI PAIRS OF SURFACE SINGULARITIES

Published online by Cambridge University Press:  05 December 2023

CHRISTOPHE EYRAL*
Affiliation:
Institute of Mathematics Polish Academy of Sciences ul. Śniadeckich 8 00-656 Warsaw Poland
MUTSUO OKA
Affiliation:
Professor Emeritus of Tokyo Institute of Technology 3-19-8 Nakaochiai Shinjuku-ku Tokyo 161-0032 Japan okamutsuo@gmail.com

Abstract

Let $f_0$ and $f_1$ be two homogeneous polynomials of degree d in three complex variables $z_1,z_2,z_3$. We show that the Lê–Yomdin surface singularities defined by $g_0:=f_0+z_i^{d+m}$ and $g_1:=f_1+z_i^{d+m}$ have the same abstract topology, the same monodromy zeta-function, the same $\mu ^*$-invariant, but lie in distinct path-connected components of the $\mu ^*$-constant stratum if their projective tangent cones (defined by $f_0$ and $f_1$, respectively) make a Zariski pair of curves in $\mathbb {P}^2$, the singularities of which are Newton non-degenerate. In this case, we say that $V(g_0):=g_0^{-1}(0)$ and $V(g_1):=g_1^{-1}(0)$ make a $\mu ^*$-Zariski pair of surface singularities. Being such a pair is a necessary condition for the germs $V(g_0)$ and $V(g_1)$ to have distinct embedded topologies.

Type
Article
Copyright
© The Author(s), 2023. Published by Cambridge University Press on behalf of Foundation Nagoya Mathematical Journal

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