Eruvin 10
רַבִּי הִיא, דְּאָמַר: בָּעִינַן שְׁנֵי פַּסִּין. דְּתַנְיָא: חָצֵר, נִיתֶּרֶת בְּפַס אֶחָד, רַבִּי אוֹמֵר: בִּשְׁנֵי פַּסִּין.
The Gemara answers: This mishna is in accordance with the opinion of Rabbi Yehuda HaNasi, who said that in order to permit carrying in a courtyard that was breached, we require two upright boards, one on either side of the breach. As it was taught in a baraita: If a courtyard was breached and opens into the public domain, and the width of the breach does not exceed ten cubits, it becomes permitted to carry there, even with only one upright board remaining on one side of the breach. Rabbi Yehuda HaNasi says: It is permitted only with two upright boards remaining, one on each side of the breach.
הַאי מַאי? אִי אָמְרַתְּ בִּשְׁלָמָא: נִרְאֶה מִבַּחוּץ וְשָׁוֶה מִבִּפְנִים — אֵינוֹ נִידּוֹן מִשּׁוּם לֶחִי, וְרַבִּי סָבַר לַהּ כְּרַבִּי יוֹסֵי, וּדְרַבִּי זֵירָא וּדְרָבִינָא לֵיתָא — מִשּׁוּם הָכִי קְטַנָּה בְּעֶשֶׂר וּגְדוֹלָה בְּאַחַת עֶשְׂרֵה, מִשּׁוּם דְּרַבִּי סָבַר לַהּ כְּרַבִּי יוֹסֵי.
The Gemara rejects this entire explanation: What is this comparison? Granted, if you say that the legal status of a side post that is visible from the outside but appears to be even with the wall from the inside is not considered like that of a side post; and that Rabbi Yehuda HaNasi holds in accordance with the opinion of Rabbi Yosei that a side post or an upright board in a courtyard must be at least three handbreadths wide; and that the explanations of the mishna offered earlier by Rabbi Zeira and Ravina are not accepted; that is why there is significance to the fact that the small courtyard is ten cubits wide and the large one is eleven cubits wide. It is due to the fact that Rabbi Yehuda HaNasi holds in accordance with the opinion of Rabbi Yosei. Since Rabbi Yosei holds that a side post must be three handbreadths wide, we require that the two upright boards together measure six handbreadths, i.e., one cubit, which is the minimal difference in size between the two courtyards.
אֶלָּא אִי אָמְרַתְּ: נִרְאֶה מִבַּחוּץ וְשָׁוֶה מִבִּפְנִים — נִידּוֹן מִשּׁוּם לֶחִי, וּדְרַבִּי זֵירָא וּדְרָבִינָא אִיתָא, וְרַבִּי לָא סָבַר לַהּ כְּרַבִּי יוֹסֵי — גְּדוֹלָה בְּאַחַת עֶשְׂרֵה לְמָה לִי?
However, if you say that the legal status of a side post that is visible from the outside but appears to be even with the wall from the inside is considered like that of a side post; and that Rabbi Zeira’s and Ravina’s explanations are accepted as halakha; and that Rabbi Yehuda HaNasi does not hold in accordance with the opinion Rabbi Yosei, why do I need to explain that the large courtyard measures eleven cubits?
מִמָּה נַפְשָׁךְ: אִי לְמִשְׁרְיַיהּ לִגְדוֹלָה קָאָתֵי — בְּעֶשֶׂר וּשְׁנֵי טְפָחִים סַגִּיא. וְאִי לְמֵיסְרַהּ לִקְטַנָּה קָאָתֵי — לְאַשְׁמוֹעִינַן דְּמַפְלְגִי טוּבָא.
Whichever way you look at it, there is a difficulty: If the baraita is coming to permit one to carry in the large courtyard, then a width of ten cubits and two handbreadths suffices. These two handbreadths can be considered the upright boards that render the courtyard fit for one to carry within it. And if it is coming to teach a novel halakha according to Rabbi Yehuda HaNasi and prohibit one to carry in the small courtyard, it should teach us a case where the walls of the two courtyards are much farther removed from each other, rather than a case where they are only one cubit apart. Therefore, the second explanation cannot be accepted.
אֶלָּא לָאו, שְׁמַע מִינַּהּ: נִרְאֶה מִבַּחוּץ וְשָׁוֶה מִבִּפְנִים — אֵינוֹ נִידּוֹן מִשּׁוּם לֶחִי. שְׁמַע מִינַּהּ.
Rather, can we not conclude from the baraita that a side post that is visible from the outside but appears to be even with the wall from the inside is not considered to have the legal status of a side post? The Gemara concludes: Indeed, conclude from this.
אָמַר רַב יוֹסֵף: לָא שְׁמִיעַ לִי הָא שְׁמַעְתְּתָא.
Rav Yosef said: I did not hear this halakha of Rabba bar Rav Huna from my teachers. Rav Yosef had become ill and forgotten his learning, which is why he could not recall the halakha that a side post that is visible from the outside is considered to have the legal status of a side post.
אֲמַר לֵיהּ אַבָּיֵי: אַתְּ אֲמַרְתְּ נִיהֲלַן, וְאַהָא אֲמַרְתְּ נִיהֲלַן — דְּאָמַר רָמֵי בַּר אַבָּא אָמַר רַב הוּנָא: לֶחִי הַמּוֹשֵׁךְ עִם דׇּפְנוֹ שֶׁל מָבוֹי, פָּחוֹת מֵאַרְבַּע אַמּוֹת נִידּוֹן מִשּׁוּם לֶחִי, וּמִשְׁתַּמֵּשׁ עִם חוּדּוֹ הַפְּנִימִי. אַרְבַּע אַמּוֹת נִידּוֹן מִשּׁוּם מָבוֹי, וְאָסוּר לְהִשְׁתַּמֵּשׁ בְּכוּלּוֹ.
His student Abaye said to him: You yourself told us this halakha, and it was with regard to this that you told it to us. As Rami bar Abba said that Rav Huna said: With regard to a side post that extends along the wall of an alleyway and beyond, in which case it appears from the inside to be a continuation of the wall but due to its narrow width it is clearly visible as a side post from the outside, if that side post is less than four cubits long it is considered to have the legal status of a side post. And one may use the alleyway up to the inner edge of the side post. However, if the side post itself extends four cubits, the alleyway has no side post and it is considered to have the legal status of an alleyway, and it is prohibited to utilize the entire alleyway.
וְאַתְּ אֲמַרְתְּ לַן עֲלַהּ: שְׁמַע מִינַּהּ תְּלָת. שְׁמַע מִינַּהּ: בֵּין לְחָיַיִן אָסוּר. וּשְׁמַע מִינַּהּ: מֶשֶׁךְ מָבוֹי בְּאַרְבַּע. וּשְׁמַע מִינַּהּ: נִרְאֶה מִבַּחוּץ וְשָׁוֶה מִבִּפְנִים נִידּוֹן מִשּׁוּם לֶחִי.
And you said to us about this: Learn from this statement three halakhot with regard to eiruvin. Learn from it that in the area between the side posts it is prohibited to carry, as Rav Huna rules that one may use the alleyway only up to the inner edge of the side post. And learn from it that the minimal length of an alleyway is four cubits. And learn from it that a side post that is visible from the outside but appears to be even with the wall of the alleyway from the inside is considered to have the legal status of a side post.
וְהִלְכְתָא: נִרְאֶה מִבַּחוּץ וְשָׁוֶה מִבִּפְנִים — נִידּוֹן מִשּׁוּם לֶחִי. תְּיוּבְתָּא וְהִלְכְתָא?
The Gemara concludes: The halakha is that a side post that is visible from the outside but appears to be even with the wall from the inside is considered to have the legal status of a side post. The Gemara asks: It is possible that there is a conclusive refutation of this opinion, and it is also the halakha? This opinion was refuted earlier. Can the halakha then be decided in accordance with it?
אִין, מִשּׁוּם דְּתָנֵי רַבִּי חִיָּיא כְּווֹתֵיהּ.
The Gemara answers: Yes, it can because Rabbi Ḥiyya taught a baraita in accordance with it. Although the deductive analysis of the statements of other tanna’im led to different conclusions, the halakha relies on Rabbi Ḥiyya’s explicit statement.
וְהָרָחָב מֵעֶשֶׂר יְמַעֵט. אָמַר אַבָּיֵי, תָּנָא: וְהָרָחָב מֵעֶשֶׂר יְמַעֵט, רַבִּי יְהוּדָה אוֹמֵר: אֵינוֹ צָרִיךְ לְמַעֵט. וְעַד כַּמָּה?
The opening mishna states: If the entrance to an alleyway is wider than ten cubits, one must diminish its width. Abaye said that a Sage taught in the Tosefta: If the entrance to an alleyway is wider than ten cubits, one must diminish its width. Rabbi Yehuda says: He need not diminish it. The question arises: Until what width does Rabbi Yehuda still permit carrying in the alleyway?
סָבַר רַב אַחַי קַמֵּיהּ דְּרַב יוֹסֵף לְמֵימַר: עַד שְׁלֹשׁ עֶשְׂרֵה אַמָּה וּשְׁלִישׁ. וְקַל וָחוֹמֶר מִפַּסֵּי בִירָאוֹת.
Initially, Rav Aḥai thought to say before Rav Yosef: Up to thirteen and a third cubits. And he derived this figure through an a fortiori argument from upright boards surrounding a well. Rabbi Yehuda maintains that if one placed upright boards up to thirteen and a third cubits apart from one another, he may consider the partitioned area around the well as a private domain and therefore carry within it.
וּמָה פַּסֵּי בִירָאוֹת שֶׁהִתַּרְתָּה בָּהֶן פָּרוּץ מְרוּבֶּה עַל הָעוֹמֵד — לֹא הִתַּרְתָּה בָּהֶן יוֹתֵר מִשְּׁלֹשׁ עֶשְׂרֵה אַמָּה וּשְׁלִישׁ, מָבוֹי שֶׁלֹּא הִתַּרְתָּה בּוֹ פָּרוּץ מְרוּבֶּה עַל הָעוֹמֵד, אֵינוֹ דִּין שֶׁלֹּא תַּתִּיר בּוֹ יוֹתֵר מִשְּׁלֹשׁ עֶשְׂרֵה אַמָּה וּשְׁלִישׁ?
Rav Aḥai explains: Just as in the case of upright boards surrounding a well, where you permitted carrying, even though the boards form a partition where the breached segment is greater than the standing segment, you did not permit carrying within them if the gap between the boards is more than thirteen and a third cubits wide; in the case of an alleyway, where you did not permit carrying if the breached segment of its walls is greater than the standing segment, is it not right that you will not permit carrying within it if there is a gap more than thirteen and a third cubits wide?
וְהִיא הַנּוֹתֶנֶת: פַּסֵּי בִירָאוֹת שֶׁהִתַּרְתָּה בָּהֶן פָּרוּץ מְרוּבֶּה עַל הָעוֹמֵד — לֹא תַּתִּיר בָּהֶן יוֹתֵר מִשְּׁלֹשׁ עֶשְׂרֵה אַמָּה וּשְׁלִישׁ, מָבוֹי שֶׁלֹּא הִתַּרְתָּה בּוֹ פָּרוּץ מְרוּבֶּה עַל הָעוֹמֵד — תַּתִּיר בּוֹ יוֹתֵר מִשְּׁלֹשׁ עֶשְׂרֵה אַמּוֹת וּשְׁלִישׁ!
But that reasoning provides support for a contrary conclusion as well. Just as in the case of upright boards surrounding a well, where you permitted carrying within them, even though the boards form a partition where the breached segment is greater than the standing segment, you will not extend the leniency and permit carrying within them, when the gap between the boards is more than thirteen and a third cubits; in an alleyway, where you were stringent and did not permit carrying when the breached segment is greater than the standing segment, in a case where most of the walls are standing, you will certainly permit carrying, even when the gap is more than thirteen and a third cubits.
אִי נָמֵי לְאִידַּךְ גִּיסָא: פַּסֵּי בִירָאוֹת דְּאַקֵּילְתְּ בְּהוּ חַד קוּלָּא — אַקֵּיל בְּהוּ קוּלָּא אַחֲרִינָא, מָבוֹי כְּלָל כְּלָל לָא.
Alternatively, one may argue to the contrary. One should be more stringent in the case of an alleyway. In the case of upright boards surrounding a well, with regard to which you were lenient and issued one leniency, be lenient and issue another leniency and maintain that a gap of up to thirteen and a third cubits still be considered an entrance. However, in the case of an alleyway, you should not be lenient at all. Therefore, there is no way to determine Rabbi Yehuda’s opinion with regard to the width of an alleyway entrance.
תָּנֵי לֵוִי: מָבוֹי שֶׁהוּא רָחָב עֶשְׂרִים אַמָּה, נוֹעַץ קָנֶה בְּאֶמְצָעִיתוֹ, וְדַיּוֹ. הוּא תָּנֵי לַהּ וְהוּא אָמַר לַהּ: דְּאֵין הֲלָכָה כְּאוֹתָהּ מִשְׁנָה. אִיכָּא דְאָמְרִי, אָמַר שְׁמוּאֵל מִשְּׁמֵיהּ דְּלֵוִי: אֵין הֲלָכָה כְּאוֹתָהּ מִשְׁנָה.
Levi taught a baraita with regard to reducing the width of an alleyway in order to render it fit for one to carry within it. If an alleyway is twenty cubits wide, one may stick a reed in the center of its entrance and that is sufficient to create two separate alleyways, each ten cubits wide. He taught this baraita, and he said about it that the halakha is not in accordance with that teaching, as the insertion of a reed is not effective in reducing the width. Some say that Shmuel said in the name of Levi: The halakha is not in accordance with that teaching.
אֶלָּא הֵיכִי עָבֵיד? אָמַר שְׁמוּאֵל מִשְּׁמֵיהּ דְּלֵוִי:
The Gemara asks: Rather, how should one act in order to render an alleyway of that sort fit for one to carry within it? Shmuel said in the name of Levi:
עוֹשֶׂה פַּס גָּבוֹהַּ עֲשָׂרָה בְּמֶשֶׁךְ אַרְבַּע אַמּוֹת, וּמַעֲמִידוֹ לְאׇרְכּוֹ שֶׁל מָבוֹי.
One prepares a board ten handbreadths high with a length of four cubits and stands it lengthwise down the middle of the alleyway, and thereby forms two small alleyways at the entrance to the alleyway, neither of which is more than ten cubits wide.
אִי נָמֵי כִּדְרַב יְהוּדָה, דְּאָמַר רַב יְהוּדָה: מָבוֹי שֶׁהוּא רָחָב חֲמֵשׁ עֶשְׂרֵה אַמָּה — מַרְחִיק שְׁתֵּי אַמּוֹת וְעוֹשֶׂה פַּס שָׁלֹשׁ אַמּוֹת.
Alternatively, one can act in accordance with the opinion of Rav Yehuda, as Rav Yehuda said: If an alleyway is fifteen cubits wide, how does one reduce its width? He distances himself two cubits from one of the walls of the alleyway and prepares a board three cubits wide, thereby leaving an opening of only ten cubits.
וְאַמַּאי? יַעֲשֶׂה פַּס אַמָּה וּמֶחֱצָה, וְיַרְחִיק שְׁתֵּי אַמּוֹת, וְיַעֲשֶׂה פַּס אַמָּה וּמֶחֱצָה. שְׁמַע מִינַּהּ: עוֹמֵד מְרוּבֶּה עַל הַפָּרוּץ מִשְׁתֵּי רוּחוֹת לָא הָוֵי עוֹמֵד!
The Gemara asks: And why must one reduce the width in this manner? One could also prepare a board a cubit and a half wide, and distance himself two cubits, and then prepare another board a cubit and a half wide, leaving the alleyway with an opening of only ten cubits. Apparently, one may conclude from the fact that Rav Yehuda did not suggest this possibility that if the standing segment of a wall is greater than the breached segment only when one combines the standing segments from two directions, i.e., both sides of the breach, it is not considered as though the standing segment were greater.
לְעוֹלָם אֵימָא לָךְ הָוֵי עוֹמֵד, וְשָׁאנֵי הָכָא, דְּאָתֵי אַוֵּירָא דְּהַאי גִּיסָא וְאַוֵּירָא דְּהַאי גִּיסָא וּמְבַטֵּל לֵיהּ.
The Gemara rejects this: Actually, I would say to you that ordinarily it is considered as standing even when one must combine the standing segments on the two sides of the breach. However, it is different here, as the air, i.e., the two cubit opening, of this one side of the far board and the air, i.e., the ten cubit opening, of this other side of the board come together and negate it. Therefore, in this case, the board that is farther from the wall cannot serve to close off the alleyway.
וְיַעֲשֶׂה פַּס אַמָּה וְיַרְחִיק אַמָּה, וְיַעֲשֶׂה פַּס אַמָּה וְיַרְחִיק אַמָּה, וְיַעֲשֶׂה פַּס אַמָּה. שְׁמַע מִינַּהּ עוֹמֵד כְּפָרוּץ — אָסוּר!
The Gemara suggests: And one could instead prepare a board one cubit wide and distance himself one cubit, and prepare another board of a cubit and distance himself one cubit, and prepare a third board of one cubit, thus ensuring that the open space is not greater than the standing segment on both sides. Apparently, since Rav Yehuda did not suggest this possibility, one may conclude from this that if the standing segment of a wall is equal to the breached segment, carrying in the alleyway is prohibited.
לְעוֹלָם אֵימָא לָךְ — מוּתָּר, וְשָׁאנֵי הָכָא דְּאָתֵא אַוֵּירָא דְּהַאי גִּיסָא וּדְהַאי גִּיסָא וּמְבַטֵּל לֵיהּ.
The Gemara rejects this assumption: Actually, I would say to you that ordinarily carrying is permitted in that case. But here it is different, since the air, the opening, on this side of the board and the air, the opening, on that side of the board come together and negate the effectiveness of the board.
וְיַרְחִיק אַמָּה וְיַעֲשֶׂה פַּס אַמָּה וּמֶחֱצָה, וְיַרְחִיק אַמָּה וְיַעֲשֶׂה פַּס אַמָּה וּמֶחֱצָה.
The Gemara suggests: And one could distance himself one cubit from the wall, and prepare a board of a cubit and a half, and distance himself another cubit, and prepare another board of a cubit and a half. In this manner, one could diminish the width of the entrance of the alleyway to ten cubits.
אִין הָכִי נָמֵי, וְכוּלֵּי הַאי לָא אַטְרְחוּהּ רַבָּנַן.
The Gemara answers: Yes, it is indeed so; this would work equally as well. But the Sages did not burden him this much, requiring him to prepare two boards where one suffices.
וְלֵיחוּשׁ דִּלְמָא שָׁבֵיק פִּיתְחָא רַבָּה, וְעָיֵיל בְּפִיתְחָא זוּטָא! אָמַר רַב אַדָּא בַּר מַתְנָה: חֲזָקָה אֵין אָדָם מַנִּיחַ פֶּתַח גָּדוֹל וְנִכְנָס בְּפֶתַח קָטָן.
The Gemara raises a new issue: But let us be concerned lest one abandon use of the larger entrance, which is ten cubits wide, and begin to enter the alleyway through the smaller entrance, which has a width of two cubits. This would negate the larger opening’s status as an entrance and render the alleyway unfit for one to carry within it, as it would no longer have an entrance with a side post. Rav Adda bar Mattana said: The presumption is that a person does not abandon a larger entrance and enter instead through a smaller entrance.
וּמַאי שְׁנָא מִדְּרַבִּי אַמֵּי וּדְרַבֵּי אַסִּי?
The Gemara raises a difficulty: And in what way is this different from the opinion of Rabbi Ami and Rabbi Asi, who maintain that in the case of an alleyway that is breached on its side wall close to its entrance, if the breach is large enough for one to enter through it, carrying in the alleyway is prohibited? There, too, such a breach should not be problematic, as a person does not abandon a larger entrance to enter through a smaller one.
הָתָם קָא מְמַעֵט בְּהִילּוּכָא. הָכָא לָא קָא מְמַעֵט בְּהִילּוּכָא.
The Gemara answers: There, in the case of Rabbi Ami and Rabbi Asi, the smaller entrance reduces his walking distance. If one approaches the alleyway from the side, the smaller entrance provides a shortcut, and therefore one might enter through it as well. However, here, in the case of the two entrances one two cubits and one ten cubits, it does not reduce his walking distance, as both openings are situated at the front of the alleyway.
תְּנַן הָתָם: עוֹר הָעַסְלָא וְחָלָל שֶׁלּוֹ — מִצְטָרְפִין בְּטֶפַח.
The Gemara returns to the issue of the standing segment that is greater than the breached segment. We learned in the Tosefta there, in tractate Kelim: The leather covering of a stool [asla] and its hole join together to complete a handbreadth with regard to ritual impurity imparted by a tent over a corpse. Any person, vessel, or food that is beneath a covering that is at least a handbreadth in size together with a portion of a corpse of at least an olive-bulk becomes ritually impure with impurity imparted by a corpse. The baraita teaches that the leather covering of a stool and its hole combine to complete the measure of a handbreadth.
מַאי ״עוֹר הָעַסְלָא״? אָמַר רַבָּה בַּר בַּר חָנָה אָמַר רַבִּי יוֹחָנָן: עוֹר כִּיסּוּי שֶׁל בֵּית הַכִּסֵּא.
The Gemara asks: What is the leather covering of a stool referred to in the Tosefta? Rabba bar bar Ḥana said that Rav Yoḥanan said: The leather covering of a bathroom.
וְכַמָּה? כִּי אֲתָא רַב דִּימִי, אָמַר: אֶצְבָּעַיִים מִכָּאן, וְאֶצְבָּעַיִים מִכָּאן, וְאֶצְבָּעַיִים רֶיוַח בָּאֶמְצַע. כִּי אֲתָא רָבִין, אָמַר: אֶצְבַּע וּמֶחֱצָה מִכָּאן, וְאֶצְבַּע וּמֶחֱצָה מִכָּאן, וְאֶצְבַּע רֶיוַח בָּאֶמְצַע.
The Gemara asks: And how large can the hole be and still combine with the leather covering to complete the handbreadth? When Rav Dimi came from Eretz Yisrael to Babylonia, he said: Two fingers of leather from here, on one side, and two fingers of leather from here, on the other side, and a space of two fingers for the hole in the middle. However, when Ravin came from Eretz Yisrael to Babylonia, he said: A finger and a half of leather from here, and a finger and a half on the leather from here, and a space of a single finger for the hole in the middle.
אֲמַר לֵיהּ אַבָּיֵי לְרַב דִּימִי: מִי פְּלִיגִיתוּ? אֲמַר לֵיהּ: לָא, הָא — בְּרַבְרְבָתָא, הָא — בְּזוּטְרָתָא, וְלָא פְּלִיגִין.
Abaye said to Rav Dimi: Do the two of you, yourself and Ravin, disagree in principle? Rav Dimi said to him: No, rather this, Ravin’s statement, is referring to the large finger, i.e., the thumb, and this, my own statement, is referring to the small finger, the pinkie, and we do not disagree. Both were describing one handbreadth, which equals the width of four thumbs or six pinkies.
אֲמַר לֵיהּ: לָאיֵי, פְּלִיגִיתוּ, וּבְעוֹמֵד מְרוּבֶּה עַל הַפָּרוּץ מִשְׁתֵּי רוּחוֹת פְּלִיגִיתוּ. לְדִידָךְ הָוֵי עוֹמֵד מִשְׁתֵּי רוּחוֹת, לְרָבִין מֵרוּחַ אַחַת — הָוֵי עוֹמֵד, מִשְׁתֵּי רוּחוֹת — לָא הָוֵי עוֹמֵד.
Abaye said to him: This is not so [la’ei]. You disagree, and you disagree with regard to the halakha in a case where the standing segment of a wall is greater than the breached segment only when one combines the standing segments from two directions, i.e., both sides of the breached segment. According to you, this wall is considered as standing, even when one must combine the standing segments from two directions. According to Ravin, if the standing segment on one side of the breach is greater, the wall is considered as standing; however, if the standing segment is greater only after combining the standing segments from the two directions, it is not considered as standing.
דְּאִי סָלְקָא דַעְתָּךְ לָא פְּלִיגִיתוּ, לְרָבִין הָכִי אִיבְּעִי לֵיהּ לְמֵימַר: אֶצְבַּע וּשְׁלִישׁ מִכָּאן, וְאֶצְבַּע וּשְׁלִישׁ מִכָּאן, וְאֶצְבַּע וּשְׁלִישׁ רֶיוַח בָּאֶמְצַע.
Abaye continues: For if it should enter your mind to say that you do not disagree, but simply refer to the same measures by different names, to express his opinion, Ravin should have said as follows: A finger and a third of leather from here, and a finger and a third of leather from here, and a space of a finger and a third for the hole in the middle. In this case, there would still be a handbreadth in total, but each side of leather alone would not be larger than the space in the middle. The fact that Ravin presented a case where the hole in the middle is smaller than the width of the leather on either side indicates that his dispute with Rav Dimi is a fundamental one.
וְאֶלָּא מַאי — פְּלִיגִינַן? לְדִידִי, הָכִי אִיבְּעִי לִי לְמֵימַר: אֶצְבַּע וּשְׁנֵי שְׁלִישִׁים מִכָּאן, וְאֶצְבַּע וּשְׁנֵי שְׁלִישִׁים מִכָּאן, וְאֶצְבָּעַיִים וּשְׁנֵי שְׁלִישִׁים רֶיוַח בָּאֶמְצַע.
Rav Dimi responds: Rather, what do you wish to say, that we disagree? If so, to express the opinion attributed to me, I should have said as follows: A finger and two thirds of leather from here, and a finger and two thirds of leather from here, and a space of two fingers and two thirds in the middle. This would provide a more striking case where, despite the fact that the breach is much greater than the standing segments on either of its sides, the two standing segments combine together so that the standing segments are considered greater than the breached segment.
אֶלָּא אִי אִיכָּא לְמֵימַר דִּפְלִגִינַן — בִּפָרוּץ כְּעוֹמֵד פְּלִגִינַן.
Rather, if there is room to say that we disagree, our dispute relates to a different point, and we argue in the case where the breached segment is exactly equal to the standing segment on each side. According to Ravin, it is considered breached; while according to Rav Dimi, it is considered standing.
אִם יֵשׁ לוֹ צוּרַת הַפֶּתַח, אַף עַל פִּי שֶׁרָחָב מֵעֶשֶׂר — אֵינוֹ צָרִיךְ לְמַעֵט. אַשְׁכְּחַן צוּרַת הַפֶּתַח דְּמַהְנְיָא בְּרַחְבּוֹ, וַאֲמַלְתְּרָא דְּמַהְנְיָא בְּגׇבְהוֹ.
The Gemara returns to the mishna: If the entrance to the alleyway has an opening in the form of a doorway, then, even if it is wider than ten cubits, one need not diminish its width. The Gemara comments: We find that an opening in the form of a doorway is effective to permit carrying in an alleyway with regard to its width, i.e., when its entrance is more than ten cubits wide, and that a cornice is effective with regard to its height, i.e., when it is more than twenty cubits high.
