On the number of places of convergence for Newton’s method over number fields

Xander Faber[1]; José Felipe Voloch[2]

  • [1] Department of Mathematics University of Georgia Athens, GA
  • [2] Department of Mathematics University of Texas Austin, TX

Journal de Théorie des Nombres de Bordeaux (2011)

  • Volume: 23, Issue: 2, page 387-401
  • ISSN: 1246-7405

Abstract

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Let f be a polynomial of degree at least 2 with coefficients in a number field K , let x 0 be a sufficiently general element of K , and let α be a root of f . We give precise conditions under which Newton iteration, started at the point x 0 , converges v -adically to the root α for infinitely many places v of K . As a corollary we show that if f is irreducible over K of degree at least 3, then Newton iteration converges v -adically to any given root of f for infinitely many places v . We also conjecture that the set of places for which Newton iteration diverges has full density and give some heuristic and numerical evidence.

How to cite

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Faber, Xander, and Voloch, José Felipe. "On the number of places of convergence for Newton’s method over number fields." Journal de Théorie des Nombres de Bordeaux 23.2 (2011): 387-401. <http://eudml.org/doc/219698>.

@article{Faber2011,
abstract = {Let $f$ be a polynomial of degree at least 2 with coefficients in a number field $K$, let $x_0$ be a sufficiently general element of $K$, and let $\alpha $ be a root of $f$. We give precise conditions under which Newton iteration, started at the point $x_0$, converges $v$-adically to the root $\alpha $ for infinitely many places $v$ of $K$. As a corollary we show that if $f$ is irreducible over $K$ of degree at least 3, then Newton iteration converges $v$-adically to any given root of $f$ for infinitely many places $v$. We also conjecture that the set of places for which Newton iteration diverges has full density and give some heuristic and numerical evidence.},
affiliation = {Department of Mathematics University of Georgia Athens, GA; Department of Mathematics University of Texas Austin, TX},
author = {Faber, Xander, Voloch, José Felipe},
journal = {Journal de Théorie des Nombres de Bordeaux},
keywords = {Arithmetic Dynamics; Newton’s Method; Primitive Prime Factors; arithmetic dynamics; Newton's method; primitive prime factors},
language = {eng},
month = {6},
number = {2},
pages = {387-401},
publisher = {Société Arithmétique de Bordeaux},
title = {On the number of places of convergence for Newton’s method over number fields},
url = {http://eudml.org/doc/219698},
volume = {23},
year = {2011},
}

TY - JOUR
AU - Faber, Xander
AU - Voloch, José Felipe
TI - On the number of places of convergence for Newton’s method over number fields
JO - Journal de Théorie des Nombres de Bordeaux
DA - 2011/6//
PB - Société Arithmétique de Bordeaux
VL - 23
IS - 2
SP - 387
EP - 401
AB - Let $f$ be a polynomial of degree at least 2 with coefficients in a number field $K$, let $x_0$ be a sufficiently general element of $K$, and let $\alpha $ be a root of $f$. We give precise conditions under which Newton iteration, started at the point $x_0$, converges $v$-adically to the root $\alpha $ for infinitely many places $v$ of $K$. As a corollary we show that if $f$ is irreducible over $K$ of degree at least 3, then Newton iteration converges $v$-adically to any given root of $f$ for infinitely many places $v$. We also conjecture that the set of places for which Newton iteration diverges has full density and give some heuristic and numerical evidence.
LA - eng
KW - Arithmetic Dynamics; Newton’s Method; Primitive Prime Factors; arithmetic dynamics; Newton's method; primitive prime factors
UR - http://eudml.org/doc/219698
ER -

References

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  1. Xander Faber and Andrew GranvillePrime factors of dynamical sequences. To appear in J. Reine Angew. Math.ArXiv:0903.1344v1. Zbl1290.11019
  2. Patrick Ingram and Joseph H. Silverman, Primitive divisors in arithmetic dynamics. Math. Proc. Cambridge Philos. Soc. 146(2) (2009), 289–302. Zbl1242.11012MR2475968
  3. Alain M. Robert, A course in p -adic analysis. Volume 198 of Graduate Texts in Mathematics. Springer-Verlag, New York, 2000. Zbl0947.11035MR1760253
  4. Joseph H. Silverman and José Felipe Voloch, A local-global criterion for dynamics on 1 . Acta Arith. 137(3) (2009), 285–294. Zbl1243.37066MR2496466

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