Spectra of degrees of some structures

Abstract

We argue for the existence of structures with the spectrum {x : x ≥ a} of degrees, where a is an arbitrary low degree. Also it is stated that there exist structures with the spectrum of degrees, {x : x ≥ a} ⊂ {x : x ≥ b}, for any low degrees a and b. © 2007 Springer Science+Business Media, Inc.