A new chapter - no-eruv eruvin. All the roofs of the city - one domain, or many? (R. Meir vs. Rabbanan) Certainly, the home itself is not the same domain as the rooftop (or the courtyard or an enclosure). But the idea of rooftops being their own domain makes sense in the way that people may use them. The Gemara notes that the same rooftops that may be lumped together as one domain are separate domains on the ground level, where each is one home, and therefore they should be treated as such (as each by itself) at the rooftop level too. Abaye now joins the discussion - to elaborate on R. Meir's opinion. Specifically, when a pillar is in a courtyard - which is treated as separate domain to train "best practices," and avoid transferring into the public domain - which would violate a Torah-level prohibition. The balancing act of remembering the prohibition... and also being able to function with an eruv on Shabbat. Also: Another R. Yosef and Abaye story. Still about the roofs and the domain...