Study Guide Eruvin 2 What are the four domains? What is an eruv? What does it permit? What is a lechi, kora, tzurat hapetach? What is the maximum height of a kora, beam and the maximum width of the opening of the alley (mavoi)? The rabbis and Rabbi Yehuda have different opinions. The gemara compares our mishna to the first mishna in Sukka and question why the language used is different. Rav says that both measurement s of the rabbis and Rabbi Yehuda are learned from the measurements of the Temple - one from the entranceway to the ulam, antechamber and one from the entranceway to the heichal, sanctuary. They are both derived from verses relating to the tabernacle. How can we learn about the temple from the tabernacle? And if so, why not from the entranceway to the courtyard of the tabernacle which was wider? The gemara brings several questions on Rav and concludes that Rabbi Yehuda did not learn from the ulam, but learned from palaces of kings.