Rigid continuation paths I. Quasilinear average complexity for solving polynomial systems
Rigid continuation paths I. Quasilinear average complexity for solving polynomial systems
复制标题
刚性连续路径 I. 求解多项式系统的拟线性平均复杂度
DOI:
10.1090/jams/938
复制
发表时间:
2017
期刊:
影响因子:
--
通讯作者:
Pierre Lairez
中科院分区:
文献类型:
--
作者:
Pierre Lairez
<p>How many operations do we need on 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 <inline-formula content-type="math/mathml">
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="left-parenthesis input size right-parenthesis Superscript 1 plus o left-parenthesis 1 right-parenthesis">
<mml:semantics>
<mml:msup>
<mml:mtext>(input size)</mml:mtext>
<mml:mrow class="MJX-TeXAtom-ORD">
<mml:mn>1</mml:mn>
<mml:mo>+</mml:mo>
<mml:mi>o</mml:mi>
<mml:mo stretchy="false">(</mml:mo>
<mml:mn>1</mml:mn>
<mml:mo stretchy="false">)</mml:mo>
</mml:mrow>
</mml:msup>
<mml:annotation encoding="application/x-tex">\text {(input size)}^{1+o(1)}</mml:annotation>
</mml:semantics>
</mml:math>
</inline-formula>. This improves upon the previously known <inline-formula content-type="math/mathml">
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="left-parenthesis input size right-parenthesis Superscript three halves plus o left-parenthesis 1 right-parenthesis">
<mml:semantics>
<mml:msup>
<mml:mtext>(input size)</mml:mtext>
<mml:mrow class="MJX-TeXAtom-ORD">
<mml:mfrac>
<mml:mn>3</mml:mn>
<mml:mn>2</mml:mn>
</mml:mfrac>
<mml:mo>+</mml:mo>
<mml:mi>o</mml:mi>
<mml:mo stretchy="false">(</mml:mo>
<mml:mn>1</mml:mn>
<mml:mo stretchy="false">)</mml:mo>
</mml:mrow>
</mml:msup>
<mml:annotation encoding="application/x-tex">\text {(input size)}^{\frac 32 +o(1)}</mml:annotation>
</mml:semantics>
</mml:math>
</inline-formula> bound.</p>
<p>The new algorithm relies on numerical continuation along <italic>rigid continuation paths</italic>. 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 average, we can compute one approximate root of a random Gaussian polynomial system of <inline-formula content-type="math/mathml">
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="n">
<mml:semantics>
<mml:mi>n</mml:mi>
<mml:annotation encoding="application/x-tex">n</mml:annotation>
</mml:semantics>
</mml:math>
</inline-formula> equations of degree at most <inline-formula content-type="math/mathml">
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper D">
<mml:semantics>
<mml:mi>D</mml:mi>
<mml:annotation encoding="application/x-tex">D</mml:annotation>
</mml:semantics>
</mml:math>
</inline-formula> in <inline-formula content-type="math/mathml">
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="n plus 1">
<mml:semantics>
<mml:mrow>
<mml:mi>n</mml:mi>
<mml:mo>+</mml:mo>
<mml:mn>1</mml:mn>
</mml:mrow>
<mml:annotation encoding="application/x-tex">n+1</mml:annotation>
</mml:semantics>
</mml:math>
</inline-formula> homogeneous variables with <inline-formula content-type="math/mathml">
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper O left-parenthesis n Superscript 4 Baseline upper D squared right-parenthesis">
<mml:semantics>
<mml:mrow>
<mml:mi>O</mml:mi>
<mml:mo stretchy="false">(</mml:mo>
<mml:msup>
<mml:mi>n</mml:mi>
<mml:mn>4</mml:mn>
</mml:msup>
<mml:msup>
<mml:mi>D</mml:mi>
<mml:mn>2</mml:mn>
</mml:msup>
<mml:mo stretchy="false">)</mml:mo>
</mml:mrow>
<mml:annotation encoding="application/x-tex">O(n^4 D^2)</mml:annotation>
</mml:semantics>
</mml:math>
</inline-formula> continuation steps. This is a decisive improvement over previous bounds that prove no better than <inline-formula content-type="math/mathml">
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="StartRoot 2 EndRoot Superscript min left-parenthesis n comma upper D right-parenthesis">
<mml:semantics>
<mml:msup>
<mml:msqrt>
<mml:mn>2</mml:mn>
</mml:msqrt>
<mml:mrow class="MJX-TeXAtom-ORD">
<mml:mo movablelimits="true" form="prefix">min</mml:mo>
<mml:mo stretchy="false">(</mml:mo>
<mml:mi>n</mml:mi>
<mml:mo>,</mml:mo>
<mml:mi>D</mml:mi>
<mml:mo stretchy="false">)</mml:mo>
</mml:mrow>
</mml:msup>
<mml:annotation encoding="application/x-tex">\sqrt {2}^{\min (n, D)}</mml:annotation>
</mml:semantics>
</mml:math>
</inline-formula> continuation steps on average.</p>
登录
查看更多内容
DOI:
10.1007/978-3-642-38896-5
发表时间:
2013-08
期刊:
--
影响因子:
--
作者:
Peter Bürgisser;F. Cucker
通讯作者:
Peter Bürgisser;F. Cucker
DOI:
10.4171/jems/789
发表时间:
2018
期刊:
arXiv: Numerical Analysis
影响因子:
--
作者:
D. Armentano;C. Beltrán;P. Bürgisser;F. Cucker;M. Shub
通讯作者:
M. Shub
DOI:
10.1515/crelle-2018-0009
发表时间:
2018
期刊:
Journal für die reine und angewandte Mathematik (Crelles Journal)
影响因子:
--
作者:
P. Bürgisser;A. Lerario
通讯作者:
A. Lerario
影响因子:
3
作者:
P. Lairez
通讯作者:
P. Lairez