Displaying similar documents to “Countable contraction mappings in metric spaces: invariant sets and measure”

Another proof of a result of Jech and Shelah

Péter Komjáth (2013)

Czechoslovak Mathematical Journal

Similarity:

Shelah’s pcf theory describes a certain structure which must exist if ℵ ω is strong limit and 2 ℵ ω > ℵ ω 1 holds. Jech and Shelah proved the surprising result that this structure exists in ZFC. They first give a forcing extension in which the structure exists then argue that by some absoluteness results it must exist anyway. We reformulate the statement to the existence of a certain partially ordered set, and then we show by a straightforward, elementary (i.e., non-metamathematical) argument that...