Halakhah for Eruvin 10:11

אמר רב חנין בר רבא אמר רב מבוי שנפרץ

R'Huna son of R'Joshua only stated his own view.<span class="x" onmousemove="('comment',' Sc. while accepting R. Huna's ruling in the case of an entrance that was no less than eight cubits in width he disagreed with it on the strength of the argument he advanced in the case of one of the width of seven.');">³²</span> R'Ashi said: It may be maintained that even [where the entrance to] an alley was eight [cubits wide] no side-post is required,<span class="x" onmousemove="('comment',' Where there was a projection of four cubits in width from one of the side walls across a part of the entrance.');">³³</span> since, whatever your assumption [might be, the ritual fitness of the alley cannot be affected]. For if the built portion is bigger<span class="x" onmousemove="('comment',' I.e., if the measurement of the projection was on a generous scale so that the so-called 'four cubits' really represented a higher figure, and the remaining space was in fact less than four cubits in width.');">³⁴</span> [the movement of objects in the alley would] be permitted by [reason of the fact that] the built portion [across the entrance] is larger than the opening; and if the open section is bigger<span class="x" onmousemove="('comment',' Cf. previous note mutatis mutandis.');">³⁵</span> [the projection]<span class="x" onmousemove="('comment',' Since it is in reality less than four cubits.');">³⁶</span> might be regarded as a side-post.<span class="x" onmousemove="('comment',' And the movement of objects would again be permitted.');">³⁷</span> What [other possible objection can] you submit? That both<span class="x" onmousemove="('comment',' The width of the projection and that of the opening.');">³⁸</span> might be exactly alike?<span class="x" onmousemove="('comment',' So that (a) the projection is four cubits wide and, therefore, unsuitable as a side-post and (b) the built section is not larger than the gap which is also four cubits wide.');">³⁹</span> [But such an assumption] would amount to an uncertainty in respect of a Rabbinical enactment,<span class="x" onmousemove="('comment',' The prohibition to move objects in an alley on the Sabbath day is not Pentateuchal but Rabbinical.');">⁴⁰</span> and in any uncertainty appertaining to a Rabbinical enactment the more lenient course is followed.<span class="x" onmousemove="('comment',' Consequently, 'no side-post is required'.');">⁴¹</span> R'Hanin B'Raba stated in the name of Rab: As to a breach that was made in an alley

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