Some stability theorems for polygons of polynomials

  title={Some stability theorems for polygons of polynomials},
  author={L. R. Pujara and Naresh R. Shanbhag},
  journal={IEEE Transactions on Automatic Control},
Some necessary and sufficient conditions for a polynomial in a polygon of polynomials to vanish on the imaginary axis are obtained. These theorems generalize the segment lemma of H. Chapellat and S.P. Bhattachartta (see ibid., vol.34, p.448-50, 1989) to a polygon of polynomials. > 

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