On Generalized Automata

Abstract

The usual notions of acceptance of automata acting on infinite strings yield sets that are in very low Borel classes. In response to a question by Landweber, Wiśniewski introduced the notion of generalized automata that yield sets at any specified level of the Borel hierachy. Here we show that most of Wiśniewski’s results can be easily derieved (and generalized) using the theory of positive analytical operations and δ – s operations.