Haar-smallest sets

Speaker(s)

Adam Kwela

Affiliation

University of Gdańsk

Date

Jan. 22, 2020, 4:15 p.m.

Room

room 5050

Seminar

Topology and Set Theory Seminar

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We will be interested in the following notions of smallness: a subset A of an abelian Polish group X is called Haar-countable/Haar-finite/Haar-n if there are a Borel set B containing A and a copy C of the Cantor set in X such that (C+x)\cap B is countable/finite/of cardinality at most n, for all x from X. We will indicate connections of the considered families to some notions raised in the literature, study their basic properties, and give suitable examples distinguishing them.

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