%0 Journal Article %A S. Cavagnetto %T The Lengths of Proofs: Kreisel's conjecture and G\"odel's speed-up theorem %J Zapiski Nauchnykh Seminarov POMI %D 2008 %P 153-188 %V 358 %I mathdoc %U http://geodesic.mathdoc.fr/item/ZNSL_2008_358_a8/ %G en %F ZNSL_2008_358_a8