Said R’ Ilai: ‘‘I have heard from R’ Eliezer: ‘Even if it is as a beis-kor.’ And I also heard from him: ‘If one of the residents of a courtyard forgot and did not participate in the eruv — his house is forbidden to him with regard to bringing into it and taking out of it, but is permitted to them.’ And I also heard from him that one fulfills his obligation on Pesach with akravnin. But I made the rounds of all his students and sought corroboration, yet I did not find.’’