Speaker: 
Hanna Stojałowska (University of Szczecin)

Title: 
Real hyperfields

Abstract:
The concept of hypergroups, which are groups with multivalued 
addition, was introduced by Marty in 1934. Few years later Krasner 
defined hyperrings and hyperfields. More recently, several authors 
studied their theory from various points of view. In this talk we 
will focus on the Artin-Schreier theory for real hyperfields, which 
was generalized to these structures by Marshall. Moreover, we will 
present the results on compatibility between orderings and valuations 
in hyperfields and we will state the Baer-Krull theorem for hyperfields.