On Constructive Existence

International audienceBaaz and Fermueller gave in 2003 an original characterization of constructive existence in classical logic. In this paper, we give a simple proof of this result based on cut-elimination in sequent calculus. The interest of this proof besides its simplicity is that it allows in particular to generalize the result to other logics enjoying cut-elimination. We also briefly discuss the significance of the characterization itself