Talk:Ordinal definable set

Relatively OD and relatively HOD
Just as we have a notion of relative constructibility (see Constructible universe), so it seems to me that there should be notions of relatively OD and relatively HOD. For example, one could allow additional parameters from a specified base set such as the real numbers to form OD(R). Could someone please find something on that and add a section to this article? JRSpriggs (talk) 01:16, 28 July 2010 (UTC)