Study Bava Batra folio 12A with parallel Hebrew-English text, traditional commentary, and modern study tools. Free access to Babylonian Talmud online.
A house that has a sealed entrance still has the 4 cubits adjoining that entrance because the entrance can be reopened. If one broke its doorposts and sealed the entrance, the entrance is completely negated, and it does not have the 4 cubits adjoining it.
There is a similar distinction with regard to the halakhot of ritual impurity. There is a halakha that a house in which there is a corpse transmits ritual impurity only through its doorways. The baraita continues: A grave whose entrance is sealed does not render all its surroundings ritually impure;
Rabba bar bar Ḥana says that R' Yoḥanan says: With regard to alleyways that are open to another city, and through which one would ordinarily travel to reach that other city, if the residents of the city in which the alleyways are located wished to block them off, the residents of the city into whi
This is due to the reasoning that Rav Yehuda says that Rav says. As Rav says: One is prohibited from ruining a path that the public has established as a public thoroughfare, i.e., steps may not be taken to prevent people from using it. This is in accordance with the statement of Rav Giddel, as Rav
Rav Anan says that Shmuel says: With regard to alleyways that open onto a public thoroughfare, if the residents of the alleyways wished to put up doors at the entrance to their alleyways, the people who use the public thoroughfare can prevent them from doing so.