2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/70365A multivariate version of Rosenblum's Fejer-Riesz theorem on outer factorization of trigonometric polynomials with operator coefficients is considered. Due to a simplification of the proof of the single variable case, new necessary and sufficient conditions for the multivariable outer factorization problem are formulated and proved.19 pagesFunctional AnalysisOptimization and Control47A68, 47B35text