Claus Scheiderer: Sums of squares and applications

Abstract: I will speak about Hilbert's work on psd
versus sos and his 17th problem, Positivstellensaetze (classic,
Schmuedgen, Putinar) and applications. And then there will be
various options: Blekherman's paper
on (3,6) and (4,4) case (relation to Gorenstein algebras), 
sos and varieties of minimal degree, and applications
of sos to semidefinite programming.