Hello.
I have been studying Arguments and Predicate when I noticed that there are two different views over Predicators: Some say that it is the main verb of the Predicate, others say that it is the finite verb while others say that it is both the finite and auxiliary verbs.
I have been doing it - Predicator: "doing";
I have been doing it - Predicator: "have";
I have been doing it - Predicator: "have been doing";
According to the representation above and bearing in mind that all representations might be correct to different perspectives, which one seems more accurate regarding most modern theories of grammar?