On a separation theorem of Rogers

Abstract

In (1) (where references and terminology may be found), C. A. Rogers has proved the following surprising theorem.Letbe a class of sets, all Souslin-in a topological space X. If A is a Souslin-set and B is an analytic set that does not meet A, then there is a Borelian-set C with A ⊂ C and C ∩ B = Ø