From: Rabbi Moshe Sofer
To: Rabbi David Deutsch
Three questions on sugyos in Pesachim are addressed: why the Gemara challenges Rava regarding Rabbi Shimon's penalty on chametz, the Ritva's principle linking lavim to ikuv for Korban Pesach registration, and whether hefker exempts one from the Pesach offering.
Source: Shu"t Chasam Sofer OC §124