Resumen de Hurewicz test sets for generalized separation and reduction

Tamás Mátrai

• We prove a Hurewicz-type theorem for generalized separation: we present a method which allows us to test if for a sequence of Borel sets (Ai)i > ? satisfying there is a sequence (Bi)i < ? of ?0? sets such that or not. We also prove an analogous result for generalized reduction. The results of the paper are motivated by a Hurewicz-type theorem of A. Louveau and J. Saint Raymond on ordinary separation of analytic sets.