MODIFIED BAR RECURSION AND CLASSICAL DEPENDENT CHOICE
Ulrich Berger, Paulo B. Oliva · 2005
We introduce a variant of Spector's bar recursion in nite types to give a realizability interpretation of the classical axiom of dependent choice allowing for the extraction of witnesses from proofs of 1 formulas in classical analysis. We also give a bar recursive denition of the fan functional and study the relationship of our variant of bar recursion with others. x1.