## Journal of the Mathematical Society of Japan

### On the set of fixed points of a polynomial automorphism

#### Abstract

Let $\Bbb K$ be an algebraically closed field of characteristic zero. We say that a polynomial automorphism $f: \Bbb K^n\to \Bbb K^n$ is special if the Jacobian of $f$ is equal to 1. We show that every $(n-1)$-dimensional component $H$ of the set ${\rm Fix}(f)$ of fixed points of a non-trivial special polynomial automorphism $f: \Bbb K^n\to\Bbb K^n$ is uniruled. Moreover, we show that if $f$ is non-special and $H$ is an $(n-1)$-dimensional component of the set ${\rm Fix}(f)$, then $H$ is smooth, irreducible and $H={\rm Fix}(f)$. Moreover, for $\Bbb K = \mathbb{C}$ if $f$ is non-special and ${\rm Jac}(f)$ has an infinite order in $\Bbb C^*$, then the Euler characteristic of $H$ is equal to 1.

#### Article information

Source
J. Math. Soc. Japan Volume 68, Number 3 (2016), 1025-1031.

Dates
First available in Project Euclid: 19 July 2016

https://projecteuclid.org/euclid.jmsj/1468956157

Digital Object Identifier
doi:10.2969/jmsj/06831025

Mathematical Reviews number (MathSciNet)
MR3523536

Zentralblatt MATH identifier
1349.14191

#### Citation

JELONEK, Zbigniew; LENARCIK, Tomasz. On the set of fixed points of a polynomial automorphism. J. Math. Soc. Japan 68 (2016), no. 3, 1025--1031. doi:10.2969/jmsj/06831025. https://projecteuclid.org/euclid.jmsj/1468956157

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