Talmud for Eruvin 1:1
מָבוֹי שֶׁהוּא גָבוֹהַּ לְמַעְלָה מֵעֶשְׂרִים אַמָּה, יְמַעֵט. רַבִּי יְהוּדָה אוֹמֵר, אֵינוֹ צָרִיךְ. וְהָרָחָב מֵעֶשֶׂר אַמּוֹת, יְמַעֵט. וְאִם יֶשׁ לוֹ צוּרַת הַפֶּתַח, אַף עַל פִּי שֶׁהוּא רָחָב מֵעֶשֶׂר אַמּוֹת, אֵין צָרִיךְ לְמַעֵט:
A mavui (an alleyway) which is higher than twenty cubits — he diminishes. [A mavui which is not wider than sixteen cubits, even though it is open on its two ends to the public domain; or else, sixteen cubits wide, but not mefulash (open on both ends), but one end open to the public domain and the other closed — By Torah law it is permitted to carry therein without any tikun (act of amendment). But the rabbis decreed against it lest he come to carry in the public domain, and they permitted it with a lechi (a stake fastened in the ground) or a korah (a beam, laid crosswise) to serve as a sign. If he placed the korah higher than twenty he "diminishes." That is, he lowers the korah below twenty. For above twenty the eye does not notice it. But if there are amaltera, i.e., designs and carvings, even above twenty cubits, it does not require lowering; for the amaltera cause it to be noticed.] R. Yehudah says: It is not necessary. [For the purpose of the korah is not to serve as a sign but to act as a partition. For we say: "The mouth of the ceiling descends and closes up." This being so, what difference does it make whether it is within twenty cubits or higher? The halachah is not in accordance with R. Yehudah.] And if it is wider than ten cubits, he diminishes. [For if it is wider than ten cubits, it is not called an "opening," but a "breach," and we require an opening. Therefore, he diminishes the width of the entrance until it is ten or less.] But if it has a tzurath hapetach ("the appearance of an entrance"), even if it is wider than ten cubits, he need not diminish. [Wherever the sages say "tzurath hapetach," there suffices even a stick on one side and a stick on the other, twenty cubits or higher, and a stick above them, even if it does not touch them, and even if it is more than three cubits above them. All of the "cubits" (amoth) mentioned in this Mishnah and in all of Eruvin, Succah, and Kilayim, are an amah of six tefachim (handbreadths); each tefach, four fingers and the thumb. It is just that sometimes the measurement must be made with "tefach atzev," i.e., not leaving any space between the two thumbs, but having them touch; and, sometimes, with space between the two thumbs, not having them touch, this being called "tefach sochek." How so? When the measurement with tefach atzev is for stringency (of ruling), as with a mavui higher than twenty cubits, in which instance he must diminish, and with a succah higher than twenty cubits, which is pasul (unfit), he measures with tefach atzev. And when the measurement with tefach sochek is for stringency, as with a mavui, which may not be lower than ten tefachim, and with a succah lower than ten tefachim, he measures with a tefach sochek; and so, in all instances.]
Jerusalem Talmud Sukkah
How the willow seven? If the seventh day of willow falls on a Sabbath, the willow is seven {days}, on all other days six5If the first day of the holiday is a Sabbath, the use of the lulav in the Temple is prescribed by Lev. 23:40 and therefore supersedes any possible Sabbath violation. But the Sabbath on any other day of the holiday week has precedence and prevents the taking of the lulav. Similarly, the willows to surround the altar were carried on the seventh day even if it was a Sabbath since one holds that on that day it is a biblical command, as explained in the Halakhah..