Whether the leniency permitting reliance on a special type of enclosure was created for all travelers, or only for those ascending to Jerusalem for the holidays: Eruvin 20b-21a
Whether the leniency was extended to all travelers, or only to those travelling for Mitzvot: Eruvin 22a [see Rashi s.v. "deLo Shechichi Metivta"]
Whether the leniency permitting this type of enclosure extends to both humans and animals, or only to animals: Eruvin 20b-21a
How much of a drinking animal or person must be inside the walls: Eruvin 20a-b, 99a-b
Holding a pail for an animal drinking from the well: Eruvin 20b, 21a
Drinking from a well which is in a public or private area, if one is standing in a Karmelit: Eruvin 99a-b
Drinking from a winecellar, which is a Karmelit: Eruvin 99a-b
Drawing from a pit into a house which is adjacent to the pit: Eruvin 99b