Full Idea
The Kripke-Feferman theory is relatively deductively very strong. In particular, it is much stronger than its competitor FS, which is based on a completely classical notion of truth.
Gist of Idea
The KF is much stronger deductively than FS, which relies on classical truth
Source
Volker Halbach (Axiomatic Theories of Truth [2011], 15.3)
Book Reference
Halbach,Volker: 'Axiomatic Theories of Truth' [CUP 2011], p.217
Related Ideas
Idea 16327 Friedman-Sheard is type-free Compositional Truth, with two inference rules for truth [Halbach]
Idea 16329 Kripke-Feferman theory KF axiomatises Kripke fixed-points, with Strong Kleene logic with gluts [Halbach]