# Rigid continuation paths I. Quasilinear average complexity for solving polynomial systems

Abstract : How many operations do we need on the average to compute an approximate root of a random Gaussian polynomial system? Beyond Smale's 17th problem that asked whether a polynomial bound is possible, we prove a quasi-optimal bound $\text{(input size)}^{1+o(1)}$. This improves upon the previously known $\text{(input size)}^{\frac32 +o(1)}$ bound. The new algorithm relies on numerical continuation along rigid continuation paths. The central idea is to consider rigid motions of the equations rather than line segments in the linear space of all polynomial systems. This leads to a better average condition number and allows for bigger steps. We show that on the average, we can compute one approximate root of a random Gaussian polynomial system of~$n$ equations of degree at most $D$ in $n+1$ homogeneous variables with $O(n^5 D^2)$ continuation steps. This is a decisive improvement over previous bounds that prove no better than $\sqrt{2}^{\min(n, D)}$ continuation steps on the average.
Type de document :
Pré-publication, Document de travail
2017
Domaine :

Littérature citée [42 références]

https://hal.inria.fr/hal-01631778
Contributeur : Pierre Lairez <>
Soumis le : jeudi 9 novembre 2017 - 16:41:23
Dernière modification le : dimanche 12 novembre 2017 - 01:07:19

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rigid-paths-1.pdf
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• HAL Id : hal-01631778, version 1

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Pierre Lairez. Rigid continuation paths I. Quasilinear average complexity for solving polynomial systems. 2017. 〈hal-01631778〉

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