Smale's Fundamental Theorem of Algebra Reconsidered
نویسندگان
چکیده
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. Our’s is polynomial in the Bézout number and the dimension of the input. Hence polynomial for any range of dimensions where the Bézout number is polynomial in the input size. In particular 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 for some fixed . 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.
منابع مشابه
Smale's point estimate theory for Newton's method on Lie groups
The γ-condition Smale's point estimate theory a b s t r a c t We introduce the notion of the (one-parameter subgroup) γ-condition for a map f from a Lie group to its Lie algebra and establish α-theory and γ-theory for Newton's method for a map f satisfying this condition. Applications to analytic maps are provided, and Smale's α-theory and γ-theory are extended and developed. Examples arising f...
متن کاملA note on spectral mapping theorem
This paper aims to present the well-known spectral mapping theorem for multi-variable functions.
متن کاملDigital Borsuk-Ulam theorem
The aim of this paper is to compute a simplicial cohomology group of some specific digital images. Then we define ringand algebra structures of a digital cohomology with the cup product. Finally, we prove a special case of the Borsuk-Ulam theorem fordigital images.
متن کاملAn Application of the Gelfand-Mazur Theorem: the Fundamental Theorem of Algebra Revisited Una Aplicación del Teorema de Gelfand-Mazur: el Teorema Fundamental del Algebra Revisitado
The main goal of this note is to give a new elementary proof of the Fundamental Theorem of Algebra. This proof is based on the use of the well known Gelfand-Mazur Theorem.
متن کاملSOME FUNDAMENTAL RESULTS ON FUZZY CALCULUS
In this paper, we study fuzzy calculus in two main branches differential and integral. Some rules for finding limit and $gH$-derivative of $gH$-difference, constant multiple of two fuzzy-valued functions are obtained and we also present fuzzy chain rule for calculating $gH$-derivative of a composite function. Two techniques namely, Leibniz's rule and integration by parts are introduced for ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Foundations of Computational Mathematics
دوره 14 شماره
صفحات -
تاریخ انتشار 2014