“Positive definite functions on groups”
Prof. Mihaly Bakonyi
Abstract: In the first part of the talk I will present a generalization of Krein's Extension Theorem stating that every positive definite operator-valued function on a symmetric interval of an ordered abelian group can be extended to a positive definite function on the entire group. In the second part, I will show that every positive definite operator-valued function on words of length <= m of the free group on n generators can be extended to a positive definite function on the whole group. Several related results will also be presented, including factorization of positive polynomials in noncommutative variables.
Time : 15.40
Place: Mathematics Seminar Room SA141
Tea will be served before the seminar.