Cohomological invariants of the Białynicki-Birula decomposition are the main subject of this dissertation. In particular we study and compare two characteristic classes: the motivic Chern class of a Białynicki-Birula cell ...

This thesis describes a functional programming language Nλ that operates on infinite structures using sets with atoms. For relational structures satisfying certain condi tions, hereditarily orbit-finite sets with atoms ...