gaps with "have" in relative clauses

well, i sure abandoned this blog for a while, didn't i?

here's a puzzle:

(1) i have a brother
(2) *the brother that i have
(3) the only/tallest brother that i have

also, compare the clearly ungrammatical (2) with the not so bad (2').

(2') (?)the book that i have

is the contrast between (2) and (2') a result of the well-known distinction between relational nouns like brother and nonrelational nouns like book? it seems not. rather, it appears to be the distinction in the kind of relation expressed by the possessive construction: (2') is grammatical because the possessive can be interpreted with an ownership interpretation, while (2), which cannot give rise to this interpretation, is ungrammatical as a result. presumably this contrast shows that where an empty category is the complement of have, the ownership relation is the only acceptable interpretation. the pattern in (4) supports this presumption.

(4) Q: what do you have in the house?
A: *a brother/*a husband/*a problem/a table/a bed

it is not surprising that the ownership interpretation is grammatically significant. partee and borschev and luca storto have both shown that this interpretation plays a role in the grammar of adnominal possessives.

what about the contrast between (2) and (3)? in general, the relevant pattern appears to be that a modifier imposing uniqueness allows a post-have gap. however, not all uniqueness-imposing modifiers have this effect. favorite, for instance, doesn't.

(5) *the favorite brother that i have