Gδ-pieces of canonical partitions of G-spaces.

Authors :: Majcher-Iwanow, Barbara
Source :: Mathematical Logic Quarterly; Sep2005, Vol. 51 Issue 5, p450-461, 12p
Publication Year :: 2005
Abstract: Generalizing model companions from model theory we define companions of pieces of canonical partitions of Polish G-spaces. This unifies several constructions from logic. The central problem of the paper is the existence of companions which form a G-orbit which is a G<subscript>δ</subscript>-set. We describe companions of some typical G-spaces. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]