Learn גמרא דף כ – last of the בעא מיניה אביי (thirteen lines from the top of the Amud) until אמר ר”א
Questions:
Why does the drying of the water from the well cause the loss of the mechitzas?
The גמרא דף יז bring the opinion of אביי that says “הואיל והותרה הותרה – once an area was permitted to carry inside it at the beginning of Shabbos that area retains its status for the entire Shabbos. This is in contradiction to our Gemara that says the drying of the water in middle of Shabbos removes the permission to carry inside the פסי ביראות ?
Learn תוס’ “מחיצה for an answer based on the גמרא דף יז
Learn ריטב”א “בעא מיניה אביי for another answer
What is the question of רבין?
Learn ריטב”א “יבשו