The small density property for Polish topometric groups

Itaï Ben Yaacov (1) , Julien Melleray (1)

1 ICJ - Institut Camille Jordan

We develop the basics of an analogue of descriptive set theory for functions on a Polish space $X$. We use this to define a version of the small index property in the context of Polish topometric groups, and show that Polish topometric groups with ample generics have this property.

Mots clés: topometric group; graded subset; graded subgroup; small index property; small density property

Domaines: Logique [math.LO]

Itaï Ben Yaacov, Julien Melleray. The small density property for Polish topometric groups. 2011. ⟨hal-00576533v1⟩