Talk:Predicate

In the framework of the set theory like ZF(C), one does not write that x belongs to a predicate, since in a set theory like NB(G) the class of all such x need not be a set, and in ZF(C) there is no notion of class. Boris (talk) 19:05, 18 March 2016 (UTC)

I like the axiomatic approach of ZF (I'm scared of C!) so I am confident with sets, I am not sure what a class is^[1], do you have any recommended reading? Alec (talk) 19:16, 18 March 2016 (UTC)

1. At the moment I think of a class as "a collection defined to have a property, which is shown to be non empty".

If you do not hate it too much   :-)   look at WP: [1]: "Such systems come in two flavors, those whose ontology consists of: * Sets alone; ** Sets and proper classes. These include Von Neumann–Bernays–Gödel set theory,..." Boris (talk) 20:22, 18 March 2016 (UTC)