Smale's Fundamental Theorem of Algebra Reconsidered

In his 1981 Fundamental Theorem of Algebra paper Steve Smale initiated the complexity theory of finding a solution of polynomial equations of one complex variable by a variant of Newton's method. In this paper we reconsider his algorithm in the light of work done in the intervening years. Smale...

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Autores principales: Armentano, D., Shub, M.
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Acceso en línea:http://hdl.handle.net/20.500.12110/paper_16153375_v14_n1_p85_Armentano
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spelling todo:paper_16153375_v14_n1_p85_Armentano2023-10-03T16:28:13Z Smale's Fundamental Theorem of Algebra Reconsidered Armentano, D. Shub, M. Fundamental Theorem of Algebra Homotopy methods Polynomial system solving Smale's 17th problem Complex variable Complexity theory Fundamental theorems Homotopy method Newton's methods Polynomial equation Polynomial system solving Smale's 17th problems Algorithms Cost benefit analysis Newton-Raphson method Polynomials Theorem proving In his 1981 Fundamental Theorem of Algebra paper Steve Smale initiated the complexity theory of finding a solution of polynomial equations of one complex variable by a variant of Newton's method. In this paper we reconsider his algorithm in the light of work done in the intervening years. Smale's upper bound estimate was infinite average cost. Ours is polynomial in the Bézout number and the dimension of the input. Hence it is polynomial for any range of dimensions where the Bézout number is polynomial in the input size. In particular it is not just for the case that Smale considered but for a range of dimensions as considered by Bürgisser-Cucker, where the max of the degrees is greater than or equal to n 1+ε for some fixed ε{lunate}. It is possible that Smale's algorithm is polynomial cost in all dimensions and our main theorem raises some problems that might lead to a proof of such a theorem. © 2013 SFoCM. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_16153375_v14_n1_p85_Armentano
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Fundamental Theorem of Algebra
Homotopy methods
Polynomial system solving
Smale's 17th problem
Complex variable
Complexity theory
Fundamental theorems
Homotopy method
Newton's methods
Polynomial equation
Polynomial system solving
Smale's 17th problems
Algorithms
Cost benefit analysis
Newton-Raphson method
Polynomials
Theorem proving
spellingShingle Fundamental Theorem of Algebra
Homotopy methods
Polynomial system solving
Smale's 17th problem
Complex variable
Complexity theory
Fundamental theorems
Homotopy method
Newton's methods
Polynomial equation
Polynomial system solving
Smale's 17th problems
Algorithms
Cost benefit analysis
Newton-Raphson method
Polynomials
Theorem proving
Armentano, D.
Shub, M.
Smale's Fundamental Theorem of Algebra Reconsidered
topic_facet Fundamental Theorem of Algebra
Homotopy methods
Polynomial system solving
Smale's 17th problem
Complex variable
Complexity theory
Fundamental theorems
Homotopy method
Newton's methods
Polynomial equation
Polynomial system solving
Smale's 17th problems
Algorithms
Cost benefit analysis
Newton-Raphson method
Polynomials
Theorem proving
description In his 1981 Fundamental Theorem of Algebra paper Steve Smale initiated the complexity theory of finding a solution of polynomial equations of one complex variable by a variant of Newton's method. In this paper we reconsider his algorithm in the light of work done in the intervening years. Smale's upper bound estimate was infinite average cost. Ours is polynomial in the Bézout number and the dimension of the input. Hence it is polynomial for any range of dimensions where the Bézout number is polynomial in the input size. In particular it is not just for the case that Smale considered but for a range of dimensions as considered by Bürgisser-Cucker, where the max of the degrees is greater than or equal to n 1+ε for some fixed ε{lunate}. It is possible that Smale's algorithm is polynomial cost in all dimensions and our main theorem raises some problems that might lead to a proof of such a theorem. © 2013 SFoCM.
format JOUR
author Armentano, D.
Shub, M.
author_facet Armentano, D.
Shub, M.
author_sort Armentano, D.
title Smale's Fundamental Theorem of Algebra Reconsidered
title_short Smale's Fundamental Theorem of Algebra Reconsidered
title_full Smale's Fundamental Theorem of Algebra Reconsidered
title_fullStr Smale's Fundamental Theorem of Algebra Reconsidered
title_full_unstemmed Smale's Fundamental Theorem of Algebra Reconsidered
title_sort smale's fundamental theorem of algebra reconsidered
url http://hdl.handle.net/20.500.12110/paper_16153375_v14_n1_p85_Armentano
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