On the Computation Cost of the Determinant of 8 ( γ , s ) : = γ 2 I − G ∼ ( s ) G ( s ) in the Guaranteed Accuracy L ∞ -

This report is concerned with the computation cost of the determinant of a (bivariate) polynomial matrix required in the guaranteed accuracy L∞-norm computation. The obtained computation cost is in terms of word operations, unlike most results available in the literature where the computation cost is provided in terms of arithmetic operations. The proposed method employs multivariate Lagrange interpolation and the computation cost in terms of word operations is shown to be polynomial in the dimensions of the system, the orders of transfer functions in the elements and the sizes of the coefficients of the polynomials.