The dynamical degree of billiards in an algebraic curve

Fuente: arXiv
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Main Author: Weinreich, Max
Format: Preprint
Published: 2023
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author Weinreich, Max
author_facet Weinreich, Max
contents We introduce an algebraic formulation of billiards on plane curves over algebraically closed fields, extending Glutsyuk's complex billiards. For any smooth algebraic curve $C$ of degree $d \geq 2$, algebraic billiards is a rational $(d-1)$-to-$(d-1)$ surface correspondence on the space of unit tangent vectors based on $C$. We prove that the dynamical degree of the billiards correspondence is at most an explicit cubic algebraic integer $ρ_d < 2d^2 - d - 3$, depending only on the degree $d$ of $C$. As a corollary, for smooth real algebraic curves, the topological entropy of the classical billiards map is at most $\log ρ_d$. We further show that the billiards correspondence satisfies the singularity confinement property and preserves a natural $2$-form. To prove our bounds, we construct a birational model that partially resolves the indeterminacy of algebraic billiards.
format Preprint
id arxiv_https___arxiv_org_abs_2305_14287
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle The dynamical degree of billiards in an algebraic curve
Weinreich, Max
Dynamical Systems
37C83, 37P05, 37F80, 37B40
We introduce an algebraic formulation of billiards on plane curves over algebraically closed fields, extending Glutsyuk's complex billiards. For any smooth algebraic curve $C$ of degree $d \geq 2$, algebraic billiards is a rational $(d-1)$-to-$(d-1)$ surface correspondence on the space of unit tangent vectors based on $C$. We prove that the dynamical degree of the billiards correspondence is at most an explicit cubic algebraic integer $ρ_d < 2d^2 - d - 3$, depending only on the degree $d$ of $C$. As a corollary, for smooth real algebraic curves, the topological entropy of the classical billiards map is at most $\log ρ_d$. We further show that the billiards correspondence satisfies the singularity confinement property and preserves a natural $2$-form. To prove our bounds, we construct a birational model that partially resolves the indeterminacy of algebraic billiards.
title The dynamical degree of billiards in an algebraic curve
topic Dynamical Systems
37C83, 37P05, 37F80, 37B40
url https://arxiv.org/abs/2305.14287