This entry is also the result of something I heard on TV the other day. I am actually unsure about the correct use of the phenomenon in question, but my guess is that what I heard cannot be correct.
The phenomenon I am referring to is possession expressed by way of the genitive, where "the ones who possess" are two or more elements, coordinated by "and" (or by some other means). In other words, if you and Mary own a horse, and you have to express this by way of the genitive, how would you go about it?; "Have you seen Mary's and my horse"? Is it then clear that we are talking about one and the same horse, or could it be two different horses? I would claim that in this example, the two elements coordinated by "and" are treated formally as separate elements, and thus the nucleus ("horse") of the NP has two determinatives. Or not? At first glance, it seems impossible to treat the coordinated expression formally as a single whole, adding the genitive only to the final word, as this would yield a completely different reading: "Have you seen Mary and my horse"? Now you are looking for both Mary and your horse.
However, I did hear this kind of expression treated as a single whole on TV the other day, but it was done differently than the last example provided here. The person in question, a native American English speaker (no, not a native american), talked about "Melissa and I's relationship". Is this not strange? I am very unsure of this phenomenon. Any opinions?