Kuratowski and Ryll-Nardzewski measurable selection theorem

The Kuratowski-Ryll-Nardzewski measurable selection theorem is an important result in the field of measure theory and functional analysis, particularly in relation to measurable spaces and measurable functions. It pertains to the existence of measurable selections from families of measurable sets. ### Theorem Statement Let \((X, \mathcal{A})\) be a measurable space, and let \(Y\) be a separable metrizable space.