Submission date: 27 January 2014.

Abstract:

[The last two sections already appeared in the first version of ArXiv:1210.4479]
We study invariant types in NIP theories. Amongst other things: we prove a definable version of the (p,q)-theorem in theories of small or medium directionality; we construct a canonical retraction from the space of M-invariant types to that of M-finitely satisfiable types; we show some amalgamation results for invariant types and list a number of open questions.

Mathematics Subject Classification: 03C45

Keywords and phrases:

Full text arXiv 1401.6715: pdf, ps.