Fri Apr 6, 2012
60 Evans Hall, 4:10–6 AM
Jouko Vaananen (University of Helsinki)
Second-Order Logic and Model Theory
Second-order logic is so strong that it makes sense to ask, are complete finitely axiomatized second-order theories always categorical? Carnap claimed that the answer is yes, but his proof did not work. Ajtai and Solovay showed that the answer depends on set theory. We present some recent new results in this field. This is joint work with Hyttinen and Kangas.