Cardinal Invariants and Rosenthal families

Prelegent(ci)

Arturo Antonio Martínez Celis Rodríguez

Afiliacja

IMPAN

Termin

31 października 2019 16:15

Pokój

p. 5050

Seminarium

Seminarium „Topologia i teoria mnogości”

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Rosenthal's lemma is a classical result that concerns sequences of measures on pairwise disjoint sets and a Rosenthal family is a collection of infinite subsets of the natural numbers that can replace the collection of all infinite subsets of natural numbers in Rosenthal's lemma. In this talk we will see that all ultrafilters are Rosenthal families and that the minimal cardinality of a Rosenthal family is r, where r is the reaping number.

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