Linearisations and the Ershov hierarchy
S. Barry Cooper, James Gay, Charles M. Harris, Kyung Il Lee, Anthony Morphett · Computability · 2017
A partial order is computably well founded if it does not computably embed a copy of ω ∗ , the order type of the negative integers. It is computably scattered if it does not computably embed a copy of η , the order type of Q . It is known that, for e