摘要
Denote the nth, mth-order polynomial sets（n】m） with real coefficients as F={f（z）|f（z）=a<sub>0</sub>z<sup>n</sup>+a<sub>1</sub>z<sup>n-1</sup>+…+a<sub>n-1</sub>z+a<sub>n</sub>,a<sub>0</sub>≠0}, G={g（z）|g（z）=b<sub>0</sub>z<sup>m</sup>+b<sub>1</sub>z<sup>m-1</sup>+…+b<sub>m-1</sub>z+b<sub>m</sub>, b<sub>0</sub>≠0}.For any f（z）, if all its roots lie within the unit circle, then f（z） is said to be astable polynomial in the discrete time sense, and denoted as f（z）∈S. For any g（z）∈G, f（z）∈F∩S,
