Vorträge im Schwerpunkt Reelle Geometrie und Algebra
Donnerstag, 20. Januar 2011, um 17:00 Uhr
in F426
(Schwerpunktskolloquium, Kuhlmann)
Prof. Heike Mildenberger
(Albert-Ludwigs-Universität Freiburg)
The cofinality of the
symmetric group and other cardinals
Abstract:
The group of permutations of the natural numbers can be written as an
increasing chain of proper subgroups. The minimal length of such a
chain is called the cofinality of the symmetric group. Its
investigation is connected to the search for interesting types of
subgroups, comparisons with other common cardinal characteristics of
the real numbers and the computation of possible lengths in various
models of set theory. There are some customised forcing extensions for
increasing these lengths.
Es wird Gelegenheit gegeben, sich vorher (ab 16.30 Uhr) im Commoncenter
F 441 bei Tee und Kaffee zu treffen.
zuletzt
geändert am 10. Januar 2011
