3 problems

Let $\textnormal{CD}^-$ be the theory obtained by restricting induction to formulae in the base language, rather than allowing induction for formulae containing the truth predicate…

The supervaluational Frege-structure theory $\mathsf{VF}$ extends Peano arithmetic with a supervaluation truth predicate, and a theory obtained by adding universes is understood an…

Let $\mathfrak{CT}^-$ and $\mathfrak{UTB}$ denote the classes of models of the corresponding theories of truth. The structural properties under consideration are: having an element…