ON THE ASYMPTOTICS OF EIGENVALUES OF SEMIDIAGONAL TOEPLITZ MATRICES

Asymptotic formulas are constructed that allow a uniform estimate of the remainder term for Toeplitz matrices of size 𝑛 for 𝑛 → ∞ in the case when their symbol 𝑎(𝑡) has the form 𝑎(𝑡) = (𝑡 − 2𝑎0 + 𝑡-1)3. This result is a generalization of the result of Stukopin et al. (2021), in which similar asymptotic formulas were obtained for a diagonal Toeplitz matrix with a symbol of a similar form when 𝑎0 = 1. The obtained formulas have high computational efficiency and generalize the results of the classical works of Parterre and Widom on the asymptotics of extreme eigenvalues.