Responsa for Bava Batra 119:13
ר' ינאי הוה ליה אילן הנוטה לרשות הרבים הוה ההוא גברא דהוה ליה נמי אילן הנוטה לרשות הרבים אתו בני רשות הרבים הוו קא מעכבי עילויה אתא לקמיה דר' ינאי א"ל
Said Raba to him: [This is not so, because] the other can say to him, I can preserve my privacy from you if you have one door, but if you have two doors I cannot.<span class="x" onmousemove="('comment',' Because if one door is shut the other may still be open. ');"><sup>10</sup></span> ON THE SIDE OF THE STREET, HOWEVER, HE MAY MAKE A DOOR FACING ANOTHER PERSON'S DOOR. [The reason is] because he can say to him: In any case you have to preserve your privacy from the eyes of the passers-by<span class="x" onmousemove="('comment',' Who can look through the door and the windows. ');"><sup>11</sup></span> [and therefore you may as well do so from me also]. <b><i>MISHNAH</i></b>. A CAVITY MUST NOT BE MADE UNDER A PUBLIC PLACE, [TO WIT,] PITS, DITCHES AND CAVES. R. ELIEZER PERMITS THIS PROVIDED [THAT THE SURFACE IS STRONG ENOUGH TO BEAR THE PASSAGE OF A WAGON LOADED WITH STONES. SPARS OR BEAMS MUST NOT BE ALLOWED TO PROJECT [FROM THE WALL OF A HOUSE] OVER THE PUBLIC WAY. THE OWNER MAY, HOWEVER, IF HE DESIRES DRAW BACK HIS WALL FROM THE STREET AND THEN ALLOW THEM TO PROJECT. IF A MAN BUYS A COURTYARD IN WHICH ARE SPARS AND BEAMS [PROJECTING], HE HAS A PRESCRIPTIVE RIGHT TO KEEP THEM THERE. <b><i>GEMARA</i></b>. [R. ELIEZER SAYS etc.] Why do the Rabbis forbid this? — Because the surface may wear thin without being noticed.<span class="x" onmousemove="('comment',' Cf. supra 27b. ');"><sup>12</sup></span> SPARS AND BEAMS MUST NOT BE ALLOWED TO PROJECT etc. R. Ammi had a spar projecting over an alley-way,<span class="x" onmousemove="('comment',' Which is private property. ');"><sup>13</sup></span> and another man had a spar projecting over a public way. [Some passers-by objected]<span class="x" onmousemove="('comment',' These words occur in our texts, but in brackets. ');"><sup>14</sup></span> and he was summoned before R. Ammi. He said to him, Go and cut it down. But, said the man, you, Sir, also have a projecting spar? Mine, he replied, projects over an alley-way the residents of which have given me their consent. Yours projects over a street; who is there to surrender the [public's] rights? R. Jannai had a tree which overhung the public way, and another man also had a tree overhanging the street. Some passers-by objected and he was summoned before R. Jannai. He said to him:
Teshuvot Maharam
A. The leaders of the community may not open any doors in the wedding-hall leading into the alley, even though they certainly have rights there, since a door that had been completely closed may not be reopened; and no new door may be opened in an alley without the permission of the inhabitants there. On the other hand, the evidence produced by the inhabitants of the alley is worthless; for leaders of a community sign a bill of sale as judges and not as witnesses; and according to the Talmud (Ket. 109a), judges sign a document without reading it and, therefore, are not responsible for its contents.
SOURCES: Pr. 118.
Teshuvot Maharam
A. Since B was in undisturbed possession of the width of the foundation, he was thus in possession of the disputed two hand-breadths of ground along the whole length of the property, and upwards reaching into the sky. Therefore, if B will take an oath to the effect that he did not remove his neighbor's landmark [when the foundation was built], the disputed two hand-breadths of ground will belong to him. Although according to Biblical law no oath is administered in disputes involving real property, such an oath is required by Rabbinic enactment.
SOURCES: Cr. 239; Am II, 184; Mord. B. B. 558; Agudah B. B. 109.