On analytic factorization of positive Hermitian matrix functions over the bidisc
The author shows that a continuous and strictly positive Hermitian matrix valued function of the bitorus may be factored as \(FF^\star,\) where \(F\) is an \((N\times\infty)\) analytic operator function. The paper also contains results for similar more general situations. This provides an operator-theoretic approach to results of \textit{T. L. Marzetta} [IEEE Trans. Acoust. Speech Signal Processing 28, 725-733 (1980; MR 82a:94022)].
positive Hermitian matrix valued function
scientific article; zbMATH DE number 1371411