Full Idea
The Friedman-Sheard truth system FS is based on compositional theory CT. The axioms of FS are obtained by relaxing the type restriction on the CT-axioms, and adding rules inferring sentences from their truth, and vice versa.
Gist of Idea
Friedman-Sheard is type-free Compositional Truth, with two inference rules for truth
Source
Volker Halbach (Axiomatic Theories of Truth [2011], 15)
Book Reference
Halbach,Volker: 'Axiomatic Theories of Truth' [CUP 2011], p.195
A Reaction
The rules are called NEC and CONEC by Halbach. The system FSN is FS without the two rules.
Related Idea
Idea 16318 Compositional Truth CT has the truth of a sentence depending of the semantic values of its constituents [Halbach]