Excerpt from Square Blocks With Equioscillation in the Pade, Walsh and Cf Tables
See [12] for information on Chebyshev approximation, for Pade, and for cf. (the CF approximant defined above is act ually the extended CF approximant in practice it would be projected onto a function rcf e Rmn to yield a near-best Chebyshev approximant on a disk.) All three problems have unique solutions, and these can be constructed rp by solving a finite Hankel system of linear equations, r* by a procedure such as the Remes algorithm, and r* via a singular value decomposition of an infinite Hankel matrix of Laurent series coefficients. We will not go into this.