pcf Theory and Applications

(Abstract)

pcf(A) collect all possible cofinality of partial order of functions on A. Shelah usd it to prove many beautiful theorems, such as

aleph_omega ^ aleph_0 <= 2 ^ aleph_0 + aleph_omega_4

on the top of his page at http://shelah.logic.at. In the talk we may introduce some theorems and to show the idea of pcf theory.