Are you Nan Li?

Claim your profile

Publications (4)0 Total impact

  • Article: Verified Error Bounds for Isolated Singular Solutions of Polynomial Systems
    Nan Li, Lihong Zhi
    [show abstract] [hide abstract]
    ABSTRACT: In this paper, we generalize the algorithm described by Rump and Graillat, as well as our previous work on certifying breadth-one singular solutions of polynomial systems, to compute verified and narrow error bounds such that a slightly perturbed system is guaranteed to possess an isolated singular solution within the computed bounds. Our new verification method is based on deflation techniques using smoothing parameters. We demonstrate the performance of the algorithm for systems with singular solutions of multiplicity up to hundreds.
    12/2012;
  • Source
    Article: Verified Error Bounds for Isolated Singular Solutions of Polynomial Systems: Case of Breadth One
    Nan Li, Lihong Zhi
    [show abstract] [hide abstract]
    ABSTRACT: In this paper we describe how to improve the performance of the symbolic-numeric method in (Li and Zhi,2009, 2011) for computing the multiplicity structure and refining approximate isolated singular solutions in the breadth one case. By introducing a parameterized and deflated system with smoothing parameters, we generalize the algorithm in (Rump and Graillat, 2009) to compute verified error bounds such that a slightly perturbed polynomial system is guaranteed to have a breadth-one multiple root within the computed bounds.
    01/2012;
  • Source
    Article: Computing Isolated Singular Solutions of Polynomial Systems: Case of Breadth One
    Nan Li, Lihong Zhi
    [show abstract] [hide abstract]
    ABSTRACT: We present a symbolic-numeric method to refine an approximate isolated singular solution $\hat{\mathbf{x}}=(\hat{x}_{1}, ..., \hat{x}_{n})$ of a polynomial system $F=\{f_1, ..., f_n\}$ when the Jacobian matrix of $F$ evaluated at $\hat{\mathbf{x}}$ has corank one approximately. Our new approach is based on the regularized Newton iteration and the computation of approximate Max Noether conditions satisfied at the approximate singular solution. The size of matrices involved in our algorithm is bounded by $n \times n$. The algorithm converges quadratically if $\hat{\xx}$ is close to the isolated exact singular solution.
    07/2010;
  • Source
    Article: A Symbolic-numeric Algorithm for Computing Isolated Singular Solutions of Nonlinear Systems Accurately: Case of Breadth One
    Nan Li, Lihong Zhi
    [show abstract] [hide abstract]
    ABSTRACT: We present a symbolic-numeric method to refine an approximate isolated singular solutio x of a polynomial system F when the Jacobian matrix of F evaluated a x has corank one. Our new approach is based on the regularized Newton iteration and the computation of Max Noether conditions satisfied at the singular solution. The method has been implemented in Maple and can deal with regular singularities and irregular singularities. For multiplicity being 2 or 3, we prove the quadratical convergence of our algorithm. Numerical experiments show that the new algorithm converges quadratically for arbitrary large multiplicity.
    04/2010; 29:9-24.

Top co-authors

Institutions