## 15. ÖMG-Kongress Jahrestagung der Deutschen Mathematikervereinigung

#### 16. bis 22. September 2001 in Wien

Sektion 4 - Mathematische Logik, Theoretische Informatik
Donnerstag, 20. September 2001, 15.30, Hörsaal 46

Some implications in infinite combinatorics

Heike Mildenberger, Universität Wien

A cardinal characteristic is a cardinal number that describes a combinatorial or analytical property of the continuum. Like the power of the continuum itself, the size of a cardinal characteristic is often independent from ZFC. However, some restrictions on possible sizes follow from ZFC. In the talk, I shall show some of these restrictions for some well-known cardinal characteristics: is the least size of an unbounded set in the order of eventual dominance on the set of functions from to , and is the groupwise density number, whose definition we shall recall in our talk.

 [1] Andreas Blass: Groupwise density and related cardinals. Arch. Math. Logic 30 (1990), 1-11. [2] Andreas Blass and Heike Mildenberger: On the cofinality of ultrapowers, Journal of Symbolic Logic 64 (1999), 727-736 [3] Heike Mildenberger: Groupwise dense families. Archive for Math. Logic 40 (2000), 93 -112.

 E-Mail: heike@logic.univie.ac.at Homepage: www.math.uni-bonn.de/people/heike

Zeitplan der Sektion   Tagesübersicht   Liste der Vortragenden