English

A note on the NFI-topology

Logic 2020-02-18 v1

Abstract

The NFINFI-topology, introduced in [S0], is a topology on the Stone space of a theory TT that depends on a reduct TT^- of TT. This topology has been used in [S0] to describe the set of universal transducers for (T,T)(T,T^-) (invariants sets that translates forking-open sets in TT^- to forking-open sets in TT). In this paper we show that in contrast to the stable case, the NFINFI-topology need not be invariant over parameters in TT^- but a weak version of this holds for any simple TT. We also note that for the lovely pair expansions, of theories with the \em wnfcp\em , the topology is invariant over \emptyset in TT^-.

Keywords

Cite

@article{arxiv.2002.06389,
  title  = {A note on the NFI-topology},
  author = {Ziv Shami},
  journal= {arXiv preprint arXiv:2002.06389},
  year   = {2020}
}
R2 v1 2026-06-23T13:42:43.225Z