Reference for Eruvin 65:8

אמר רבינא רישא דאית ביה ארבעה סיפא דלית ביה ארבעה וכלכלה משלימתו לארבעה

If [it is one] which is less than four [handbreadths in width,] then, surely, it is a spot of exemption;<span class="x" onmousemove="('comment',' I.e., a spot the identity of which is merged into the domain in which it is situated (v. Shab. 6a) , so that it is permitted, even in Rabbinic law, to move objects from the former into the latter and vice versa. As the tree in question is situated in a public domain it is permitted to move the 'erub from the one into the other. Why then should the 'erub be ineffective even where it lay at a height above ten handbreadths?');">²⁴</span> and if it was four [handbreadths wide,]<span class="x" onmousemove="('comment',' So that the prohibition in the first clause is due to the fact that the tree constituted a private domain from which it is forbidden to carry into the public domain.');">²⁵</span> what is [the use, it may be asked,] that the 'erub was put in a basket?<span class="x" onmousemove="('comment',' Seeing that neither the 'erub alone nor the 'erub with the basket may be moved from one domain into another.');">²⁶</span> - Rabina replied: The first clause [is a case] where [the tree] had [a width] of four [handbreadths,<span class="x" onmousemove="('comment',' As the tree thus constituted a private domain the 'erub on it could not be carried to the 'abode' in the public domain. Hence the invalidity of the 'erub.');">²⁷</span> while] the final clause [deals with one] whose width was less than four [handbreadths]<span class="x" onmousemove="('comment',' In consequence of which it cannot be regarded as a private domain.');">²⁸</span> but the basket supplemented it to four

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