Bava Batra 21 - July 16, 10 Tamuz

Why can courtyard residents prevent each other from turning their house into a store (first part of the Mishna) but not from loud noises of children, hammers, and a millstone (second part of the Mishna)? Abaye suggests that the second part of the Mishna refers to a different situation - residents of a different courtyard complaining about noise from a neighboring courtyard, but not their own. Rava rejects this suggestion and explains the second part of the Mishna as referring to creating a school in one's house to teach children Torah, as Rabbi Yehoshua ben Gamla established the importance of having schools in local communities. The Gemara discusses several issues regarding education - what type is the best type of teacher (more knowledge vs. patience to correct mistakes of the children), how many children should be in a class, the responsibility of the city to set up teachers, does one fire a less good teacher for one who is better, etc. Can one open a store in an alleyway of the same type of store as another member of the alleyway? On what does it depend?