Whether the prohibition against carrying within a yard [if the adjoining houses haven't merged with each other] refers only to introducing items from a house into the yard, or even to transporting items entirely within the yard: Shabbat 130b-131a; Eruvin 23b, 35a, 74a, 89a, 90b-91a, 91a-92a
Transportation Between Yards
King Solomon created the decree forbidding transportation between two adjacent, unmerged private properties: Eruvin 21b
When King Solomon created this decree, a Divine Voice announced, "My son, if your heart is wise, My Heart is glad!": Eruvin 21b
Whether the prohibition against carrying within a yard [if the adjoining houses haven't merged with each other] refers only to introducing items from a house into the yard, or even to transporting items entirely within the yard: Shabbat 130b-131a; Eruvin 23b, 35a, 74a, 89a, 90b-91a, 91a-92a
Use of a Shared Area which is between Two Yards
The status of an area which is accessible from two different yards, where the yards did not merge with each other: Eruvin 83b-85b
Making walls around a pit which is between two private yards, to allow the drawing of water: Eruvin 86a; Succah 16a-b
Using an animal as part of the wall around a shared pit between two yards: Succah 23a
Using reeds/trees as part of the wall around a shared pit between two yards: Succah 24b
Permitting use of a pit which is between two yards if there is a distance of four cubits between each yard and the pit, even though they each make structural changes to permit them to draw from the pit: Eruvin 84b-85b
The status of a ruin which is between two yards, where the residents of one of the yards have merged and the residents of the other have not: Eruvin 92a
The status of a space which is between two yards, and which is not its own independent area: Eruvin 77a, 83b
What happens if residents of a yard and an adjacent elevated porch forget to merge with each other: Eruvin 83b-84a, 91b
What happens if residents of a yard and an upper floor forget to merge with each other: Eruvin 84a
What happens if residents of some houses dig a pit into which water could be poured on Shabbat, and some did not: Eruvin 88a