Ruy de Queiroz

[1] He is the founder of the Workshop on Logic, Language, Information and Computation (WoLLIC), which has been organised annually since 1994, typically in June or July.

In the late 1980s, Ruy de Queiroz has offered a reformulation of Martin-Löf type theory based on a novel reading of Wittgenstein’s "meaning-is-use", where the explanation of the consequences of a given proposition gives the meaning to the logical constant dominating the proposition.

[3] Since later in the 1990s, Ruy de Queiroz has been engaged, jointly with Dov Gabbay, in a program of providing a general account of the functional interpretation of classical and non-classical logics via the notion of labeled natural deduction.

As a result, novel accounts of the functional interpretation of the existential quantifier, as well as the notion of propositional equality, were put forward, the latter allowing for a recasting of Richard Statman's notion of direct computation, and a novel approach to the dichotomy "intensional versus extensional" accounts of propositional equality via the Curry–Howard correspondence.

Since the early 2000s, Ruy de Queiroz has been investigating, jointly with Anjolina de Oliveira, a geometric perspective of natural deduction based on a graph-based account of Kneale's symmetric natural deduction.