It's easy to see how an extensional definition is just the elements of a set, but what about the notions of descriptions of the properties, axioms, and rules that can be used to define a set?
Asked
Active
Viewed 68 times
1
-
The notion of a definable set, and the connection between a particular formula and the set it defines (in a given structure), is a relevant one; are you already familiar with this? (If not, see here.) – Noah Schweber Sep 27 '22 at 18:16
-
This starts getting you into mathematical logic. In addition to Noah's reference on definable sets, you might also be interested in a result like Beth's definability theorem. – blargoner Sep 27 '22 at 18:42
-
Thank you! @NoahSchweber Did you write that book yet? ;) – csp Sep 27 '22 at 19:03