Zwei Vorträge (sh. Abstracts)

Speaker: Sebastiaan Terwijn

 

Title: Constructive logic and the Medvedev lattice.

 

Abstract:

The Medvedev lattice is a structure from computability

theory that is interesting for various reasons. It was

originally introduced for its connections with constructive

logic, but it is also interesting in other respects, for

example in connection with computation on the reals, the

study of Pi-0-1 classes, algorithmic randomness, or as a

generalization of the Turing degrees.

In this talk we discuss the connections between algebraic

properties of the lattice on the one hand, and constructive

logic on the other.

 

Speaker: Rosalie Iemhoff

 

Title: Skolemization and Herbrand's theorem in non-classical theories.

 

We present and alternative to Skolemization for non-classical theories

for which regular Skolemization fails. This method makes use of an

existence predicate, and, like Skolemization, replaces strong quantifiers

by terms. From this we derive a variant of Herbrand's theorem, which we

apply to several theories, including the constructive theory of equality,

intuitionistic logic, and fuzzy logics.