Pohlers's ordinal analysis in his monograph  contains some flaws and thereby ends up with incorrect proof-theoretic ordinals of several systems. The present paper determines their correct proof-theoretic ordinals and also supplements  with the ordinal analysis of some other relevant impredicative systems.
|Number of pages||55|
|Journal||Annals of Pure and Applied Logic|
|Early online date||16 Dec 2014|
|Publication status||Published - 1 Apr 2015|