Crouzeix's Conjecture Holds for Tridiagonal 3 x 3 Matrices with Elliptic Numerical Range Centered at an Eigenvalue

  title={Crouzeix's Conjecture Holds for Tridiagonal 3 x 3 Matrices with Elliptic Numerical Range Centered at an Eigenvalue},
  author={Christer Glader and Mikael Kurula and M. Lindstr{\"o}m},
  journal={SIAM J. Matrix Anal. Appl.},
Crouzeix stated the following conjecture in [Integral Equations Operator Theory, 48 (2004), pp. 461-477]: For every n x n matrix A and every polynomial p, |p(A)| le 2 max_z in W(A)|p(z)|, where W(A... 
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