The E-type theory of donkey anaphora requires each pronoun be unique (within a situation). To this end, Heim follows Berman in claiming that (1) means (2):
Now, imagine that Farmer Joe owns three donkeys (total). According to the definitions Heim assumes, then, there are three minimal situations such that Joe owns a donkey; and each of these situations contains exactly one man and exactly one donkey. This allows the pronouns "he" and "it" to refer to a man unique to the situation and a donkey unique to the situation. So far, so good.
Consider Heim's (presumed) meaning for (3), given in (4), though:
Notice that (4) means exactly the same thing as (2), since every minimal situation where a man owns a donkey is a minimal situation where a man owns exactly one donkey. If this is right, however, then (1) and (3) should be synonymous. But they aren't. Comments?