Possessives as nominal group heads
The possessive pronouns mine, yours, his, hers, (its), ours, theirs function not as determinatives but as pronominal heads. (Its is not used to realize this function.)
This suitcase is yours. Where is mine? It’s over there with Tom’s.
The ’s phrase stands alone as an ellipted head of the NG when the noun head is recoverable, either because it is known already, or by convention. In the latter case the ’s element often refers to people’s homes or establishments such as restaurants and shops, as well as to individuals:
Let’s have dinner at Archy’s. These gloves aren’t mine, they’re Daniel’s.
I have to go to the cleaner’s (dry cleaner’s), the hairdresser’s , the florist’s.
A friend of mine, a friend of my sister’s
The post-modifying possessive phrase of mine, of yours etc. is equivalent to the ‘double possessive’ as in a friend of my sister’s. They have the meaning of ‘one among several’ as opposed to the more exclusive meaning of ‘my friend’, ‘my sister’s friend’. An exclusive meaning, which may also express an attitude on the part of the speaker, is found, however, when the phrase occurs together with another determinative (this, that, a, the, other, etc.), a combination that is not possible otherwise:
That motorcycle of your brother’s
