Alexandra A. Soskova
The enumeration degree spectrum DS(A) of a countable structure A is the set
of all enumeration degrees of the presentations of A on the natural numbers.
The co-spectrum of A is the set of all lower bounds of DS(A). The talk is
a survey on the relationships between the degree spectrum and the co-spectrum of A.
We will discuss also a Jump inversion theorem for degree spectra and some applications of it.