Seminários de Lógica Matemática 13 de Novembro 2008, 18h00 Abstract: Bar recursion is an intuitionistic form of transfinite recursion over well-founded trees. It is at first somewhat opaque for the classically minded since it is not well-defined in the full set- theoretic universe. In this talk, we connect bar recursion with classical transfinite recursion and show that bar-recursion is (classically) well-defined in the structure of majorizable functionals. We also discuss bar-induction, which is a form of transfinite induction and which is intimately connected with the axiom of dependent choices. | back |