  Let us consider a first-order language L, with connective &amp;, ∨, and ¬, quantifiers ∀ and ∃, the equals sign =, variables, and some stock of names, function symbols and relation symbols. We will say that L is a truth language, if it has a distinguished predicate T and quotation marks ‘ and ’, which will be used to form quote names: if A is a sentence of L, then ‘A’ is a name. Let SentL = {A : A is a sentence of L}.