Analytic partial orders and oriented graphs
Fundamenta Mathematicae 192 (2006), 233-243 MSC: Primary 03E15, 04A15. DOI: 10.4064/fm192-3-3
We prove that there is no maximum element, under Borel reducibility, in the class of analytic partial orders and in the class of analytic oriented graphs. We also provide a natural jump operator for these two classes.