Improved fewnomial upper bounds from Wronskians and dessins d'enfant

Fuente: arXiv
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Autori principali: Hilany, Boulos El, Tavenas, Sébastien
Natura: Preprint
Pubblicazione: 2024
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author Hilany, Boulos El
Tavenas, Sébastien
author_facet Hilany, Boulos El
Tavenas, Sébastien
contents We use Grothendieck's dessins d'enfant to show that if $P$ and $Q$ are two real polynomials, any real function of the form $x^α(1-x)^β P - Q$, has at most $°P +°Q + 2$ roots in the interval $]0,~1[$. As a consequence, we obtain an upper bound on the number of positive solutions to a real polynomial system $f=g=0$ in two variables where $f$ has three monomials terms, and $g$ has $t$ terms. The approach we adopt for tackling this Fewnomial bound relies on the theory of Wronskians, which was used in Koiran et.\ al.\ (J.\ Symb.\ Comput., 2015) for producing the first upper bound which is polynomial in $t$.
format Preprint
id arxiv_https___arxiv_org_abs_2409_01651
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Improved fewnomial upper bounds from Wronskians and dessins d'enfant
Hilany, Boulos El
Tavenas, Sébastien
Algebraic Geometry
Combinatorics
Functional Analysis
14P25, 30D30, 14Q99
We use Grothendieck's dessins d'enfant to show that if $P$ and $Q$ are two real polynomials, any real function of the form $x^α(1-x)^β P - Q$, has at most $°P +°Q + 2$ roots in the interval $]0,~1[$. As a consequence, we obtain an upper bound on the number of positive solutions to a real polynomial system $f=g=0$ in two variables where $f$ has three monomials terms, and $g$ has $t$ terms. The approach we adopt for tackling this Fewnomial bound relies on the theory of Wronskians, which was used in Koiran et.\ al.\ (J.\ Symb.\ Comput., 2015) for producing the first upper bound which is polynomial in $t$.
title Improved fewnomial upper bounds from Wronskians and dessins d'enfant
topic Algebraic Geometry
Combinatorics
Functional Analysis
14P25, 30D30, 14Q99
url https://arxiv.org/abs/2409.01651